Safety of High Speed Ground U. S. Department Transportation Systems of Transportation Federal Railroad Administration
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DOT/FRA/ORD-97/05 Final Report Approved for U.S. Government use only. DOT-VNTSC-FRA-96-6 April 1997 Exempted from public availability to protect intellectual property rights of designers. Transmittal of this document outside of the U.S. Government must have prior approval of the Director of Research and Development, F? NOTICE
This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof.
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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED A p r i l 1 9 9 7 Final Report - April 1996
4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Safety of High Speed Ground Transportation Systems: Technical Descriptions of Advanced Braking Concepts for High Speed RR693/R6019 Ground Transportation ______
6. AUTHOR(S) David P. Wagner, Donald R. Ahlbeck, Jonathan F. Luedeke, Scott D. Cook, Mark A. Dielman
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION B a t t e l l e REPORT NUMBER 505 King Avenue Columbus, OH 43201 DOT-VNTSC-FRA-96-6
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING U.S. Department of Transportation AGENCY REPORT NUMBER Federal Railroad Adm inistration Office of Research and Development DOT/FRA/ORD-97/05 W a s h i n g t o n , D C 2 0 5 9 0 ______
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE
This document is available to the public through the National Technical Information Service, Springfield, VA 22161
13. ABSTRACT (Maximum 200 words)
The objective of this study is to develop qualitative and quantitative information on the various braking strategies used in high-speed ground transportation systems in support of the Federal Railroad Administration (FRA). The approach employed in th is study is composed of two steps: f ir s t , build a technical understanding of the various braking strategies, and second, perform a safety analysis for each system. The systems considered in this study include seven operating high-speed rail transportation systems and three existing magnetic levitation systems. The principal technique used in the system safety analysis is Failure Modes and Effects Analysis (FMEA), an inductive approach to identifying system failure modes that depends on a thorough understanding of the system design and operation. Key elements derived from the system safety analysis are the fault-tolerant and fail-safe characteristics of the braking systems. This project memorandum contains proprietary information in both the technical descriptions and the FMEAs which does not appear in the companion volume, "Safe ty of High Speed Ground Transportation Systems: Safety of Advanced Braking Concepts fo r High Speed Ground Transportation Systems" (DOT-VNTSC-FRA-95-14; DOT/FRA/ORD-95/09.1). As such, d istrib u tio n is lim ited as noted on the cover.
14. SUBJECT TERMS 15. NUMBER OF PAGES 204 high-speed, rail, magnetic leviation, braking equipment, fault- tolerant, fail-safe, FMEA, safety, failure modes 16. PRICE CODE
17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT Unclassified Unclassified Unclassified
NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. 239-18 298-102 PREFACE
The Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) generated renewed interest in establishing high-speed guided ground transportation (HSGGT) service in the U.S.* These initiatives range from traditional rail service (though upgraded to accommodate higher speeds) to advanced technologies such as magnetically levitated (maglev) trains. As part of a comprehensive review of the safety and reliability of the proposed HSGGT systems, this current study of advanced braking systems examines the various strategies used to brake these high-speed vehicles safely, reliably, and efficiently.
This report contains the detailed technical descriptions and system safety worksheets developed to support the study of the safety of HSGGT advanced braking concepts. These descriptions, in part, are derived from proprietary data supplied by trainset manufacturers and operators to support U.S. government investigations related to HSGGT safety and operating practices. This report thus contains proprietary data and is subject to limited distribution. A separate summary report containing the results and conclusions of this study has been published for general distribution.
This work was performed by a team comprising Battelle, TransTech Management, and Booz Allen & Hamilton for the Volpe National Transportation Systems Center under contract #DTRS-57-93-D-00027 Task No. VA 3207. This work is part of a broader program on HSGGT safety being conducted by the Volpe Center in support of the FRA Office of Research and Development.
’High speed is defined as exceeding 200 km/hr (125 mph).
in METRIC/ENGL 1SH CONVERSION FACTORS
ENGLISH TO METRIC METRIC TO ENGLISH LENGTH (APPROXIMATE) LENGTH (APPROXIMATE) 1 inch (in) = 2.5 centimeters (cm) 1 millimeter (mm) = 0.04 inch (in) 1 foot (ft) = 30 centimeters (cm) 1 centimeter (cm) = 0.4 inch (in) 1 yard (yd) = 0,9 meter (m) 1 meter (m) = 3.3 feet (ft) 1 mile (mi) = 1.6 kilometers (km) 1 meter (m) =1.1 yards (yd) 1 kilometer (k) = 0.6 mile (mi)
AREA (APPROXIMATE) AREA (APPROXIMATE) 1 square inch (sq in, in2) = 6.5 square centimeters (cm2) 1 square centimeter (cm2) = 0.16 square inch (sq in, in2) 1 square foot (sq ft, ft2) = 0.09 square meter (m2) 1 square meter (m2) =1.2 square yards (sq yd, yd2) 1 square yard (sq yd, yd2) = 0.8 square meter (m2) 1 square kilometer (km2) = 0.4 square mile (sq mi, mi2) 1 square mile (sq mi, m i) = 2.6 square kilometers (tarn) 10,000 square meters (m2) = 1 hectare (he) = 2.5 acres 1 acre = 0.4 hectare (he) = 4,000 square meters (m2)
MASS - WEIGHT (approximate ) MASS - WEIGHT (approximate ) 1 ounce (oz) = 28 grams (gm) 1 gram (gm) = 0.036 ounce (oz) 1 pound (lb) = 0.45 kilogram (kg) 1 kilogram (kg) = 2.2 pounds (lb) 1 short ton = 2,000 pounds (lb) = 0.9 tonne (t) 1 tonne (t) = 1,000 kilograms (kg) = 1.1 short tons
VOLUME (APPROXIMATE) VOLUME (APPROXIMATE) 1 teaspoon (tsp) = 5 milliliters (ml) 1 milliliter (ml) = 0.03 fluid ounce (fl oz) 1 tablespoon (tbsp) = 15 milliliters (ml) 1 liter (I) = 2.1 pints (pt) 1 fluid ounce (fl oz) = 30 milliliters (ml) 1 liter (!) = 1.06 quarts (qt) 1 cup (c) = 0.24 liter (I) 1 liter (I) = 0.26 gallon (gal) 1 pint (pt) = 0.47 liter (I) 1 quart (qt) = 0.96 liter (I) 1 gallon (gal) = 3.8 liters (I) 1 cubic foot (cu ft, ft3) = 0.03 cubic meter (m3) 1 cubic meter (m3) = 36 cubic feet (cu ft, ft3) 1 cubic yard (cu vd, yd3) = 0.76 cubic meter (m3) 1 cubic meter (m3) = 1.3 cubic yards (cu yd, yd3)
TEMPERATURE (e x a c t ) TEMPERATURE (e x a c t ) f(x-32)(5/9)l °F = v °C 1(9/5) v + 321 °C = X °F
QUICK INCH - CENTIMETER LENGTH CONVERSION — o l 3 4 5
inches ______l ______L______1 1 1 1 1 i f iii iir Centimeters 0 1 2 3 4 5 6 7 8 9 10 11 12 13
QUICK FAHRENHEIT - CELSIUS TEMPERATURE CONVERSION °F -40° -22° -4® 14° 32° 50° 68° 86° 104° 122° 140° 158° 176° 194° 212® I--- 1------1------1------1------1------1------1------\------1------1-1-- 1------1---- 1 °C -40° -30° -20° -10° 0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 100°
For more exact and or other conversion factors, see NB S Miscellaneous Publication 286, Units of Weights and Measures. Price $2.50 SD Catalog No. C1 3 10286 Updated 1/23/35
IV TABLE OF CONTENTS
Section Page
1. INTRODUCTION...... 1-1
2. BACKGROUND...... 2-1
2.1 TECHNICAL DESCRIPTION OF BRAKING SYSTEMS ...... 2-1
2.2 SYSTEM SAFETY ANALYSIS ...... 2-10
2.3 CURRENT REGULATIONS ...... 2-12
3. TECHNICAL DESCRIPTION OF BRAKING SYSTEM S...... 3-1
3.1 AMTRAK METROLINER SERVICE (NORTHEASTCORRIDOR) ...... 3-1
3.1.1 General Description of Trainset...... 3-1 3.1.2 Braking System Design ...... 3-1 3.1.3 Braking System Performance ...... 3-5
3.2 X2000 TILTING TRAIN...... 3-13
3.2.1 ‘ General Description of Trainset...... 3-13 3.2.2 Braking System Design ...... 3-14 3.2.3 Braking System Performance ...... 3-22
3.3 INTERCITY EXPRESS (ICE) ...... 3 .3 7
3.3.1 General Description of Trainset...... 3-37 3.3.2 Braking System Design ...... 3-37 3.3.3 Braking System Performance ...... 3-44 3.3.4 Braking System Effects on Vehicle, Guideway & Infrastructure . . 3-45
3.4 TGV ATLANTIQUE...... 3-53
3.4.1 Description of Trainset...... 3-53 3.4.2 Braking System Design ...... 3-53 3.4.3 Braking System Performance ...... 3-55
3.5 BRITISH RAIL INTERCITY 125...... 3-68
3.5.1 Description of Trainset...... 3-68 3.5.2 Braking System Design ...... 3-68 3.5.3 System Operation and Control...... 3-71
v T A B L E O F CO N T E N T S (cont.)
Section Page
3.5.4 Safety Features...... 3-72 3.5.5 Technical Specifications of the Braking System ...... 3-74 3.5.6 Environmental Considerations ...... 3-75 3.5.7 Inspection and Test Requirements...... 3-76
3.6 BRITISH RAIL INTERCITY 225 ...... 3-78
3.6.1 Description of Trainset ...... 3-78 3.6.2 Braking System Design ...... 3-78 3.6.3 System Operation and Control ...... 3-82 3.6.4 Safety Features ...... 3-84 3.6.5 Technical Specifications of the Braking System ...... 3-86 3.6.6 Environmental Considerations ...... 3-88 3.6.7 Inspection and Test Requirements ...... 3-89
3.7 SHINKANSEN TRAINS ...... 3-102 / 3.7.1 Description of Trainsets ...... 3-102 3.7.2 Braking System Design ...... 3-102 3.7.3 Braking System Performance ...... 3-102 3.7.4 Braking System Operation, Control and Safety Features ...... 3-104 3.7.5 Braking System Effects on Vehicles, Guideway, and Infrastructure ...... 3-106
3.8 ETR450 ...... 3-118
3.8.1 Description of Trainset...... 3-118 3.8.2 Braking System Design ...... 3-118 3.8.3 Braking S ystem Performance ...... 3-118 3.8.4 Braking System Operation, Control and Safety Features...... 3-119 3.8.5 Braking System Effects on Vehicles, Guideway, and Infrastructure ...... 3-119
3.9 TRANSRAPID TR07...... 3-119
3.9.1 General Description...... 3-119 3.9.2 Braking System Design ...... 3-120 3.9.3 Brake System Operation...... 3-128 3.9.4 Brake System Performance...... 3-130
vi T A B L E OF CO N T E N T S (cont.)
Section Page
3.10 HSST...... 3-140
3.10.1 General Description...... 3-140 3.10.2 Braking System Design ...... 3-140 3.10.3 Brake System Operation...... 3-146 3.10.4 Brake System Performance...... 3-146
3.11 MLU-002N...... 3-151
3.11.1 General Description...... 3-151 3.11.2 Braking System Design ...... 3-151 3.11.3 Brake System Operation...... 3-160 3.11.4 Brake System Performance...... 3-162
APPENDIX A ...... A-l
REFERENCES ...... R-l
vn LIST OF FIGURES
Figure Page
Figure 2-1 Schematic of Typical Automatic Air Brake System (Ref. 1 )...... 2-3
Figure 2-2 Schematic of Typical Electro-Pneumatic Brake System (Ref. 1 ) ...... 2-4
Figure 2-3 Coefficient of Adhesion Versus Speed for Tread Braked Vehicles (Ref. 2) ...... 2-6
Figure 2-4 Typical Relationship Between Adhesion and Wheel Slip (Ref. 3 ) ..... 2-7
Figure 2-5 Graph of Braking Performance of BR Intercity 125 Train (Ref. 3) .... 2-8
Figure 2-6 Braking Diagram for ICE Train Showing Eddy Current Braking Effort (Ref. 4) ...... 2-9
Figure 3-1 Dynamic Braking Performance of the AEM-7 Locomotive (Ref. 5) . . . 3-3
Figure 3-2 Typical U.S. Passenger Train Pneumatic Brake System (Ref. 1 ) ...... 3-4
Figure 3-3 Schematic Diagram of X2000 Train Pneumatic Brake System (Ref. 1 0 ) ...... 3-18
Figure 3-4 Schematic of Pneumatic Brake Equipment on X2000 Trainset Power C a r ...... 3-20
Figure 3-5 Calculated Stopping Distance vs. Speed for X2000 Trainset...... 3-23
Figure 3-6 Brake Control Schematic for ICE Power Car (Ref. 1 2 ) ...... 3-41
Figure 3-7 Brake Control Schematic for ICE Trailer Car (Ref. 1 2 ) ...... 3-42
Figure 3-8 Diagnostic System of ICE Trainset (Ref. 1 3 ) ...... 3-46
Figure 3-9 Schematic Diagram of Series 200 Trainset Brake System (Ref. 23) . . ..3-103
Figure 3-10 Speed vs. Deceleration Characteristics for the Series 300 (Nozomi) Trainset (Ref. 24) ...... 3-105
Figure 3-11 Schematic Diagram of Series 300 (Nozomi) Trainset Brake System (Ref. 24) ...... 3-107
Figure 3-12 Brake Circuits and Control of Brake Magnets (Ref. 2 6 ) ...... 3-122
vm LIST OF FI G U R E S (cont.)
Figure Page
Figure 3-13 Simplified Block Diagram of TR07 OCS (Ref. 2 7 ) ...... 3-124
Figure 3-14 Block Diagram of Brake Circuit for Eddy Current Brake System (Ref. 26) ...... 3-126
Figure 3-15 Horizontal Brake Force as a Function of Vehicle Speed (Ref. 2 8 )...... 3-131
Figure 3-16 Brake Current as a Function of Vehicle Speed ...... 3-132
Figure 3-17 Deceleration Curves for the TR07 in Eddy Current BrakingMode . . . .3-133
Figure 3-18 Deceleration Curve for TR07 on Braking Skids (Ref. 28) ...... 3-134
Figure 3-19 HSST Hydraulic Brake Caliper Assembly ...... 3-142
Figure 3-20 Vehicle Control System and Subsystems...... 3-144
Figure 3-21 Block Diagram of Levitation Control System ...... 3-145
Figure 3-22 Disk Brake System for MLU002N ...... 3-154
Figure 3-23 Several Views of Aerodynamic Brakes ...... 3-156
Figure 3-24 Opened Aerodynamic Brake Panels ...... 3-157
Figure 3-25 Double Bogie Frame With Landing Skids ...... 3-158
Figure 3-26 Operational Safety System ...... 3-159
Figure 3-27 Control Circuits for Aerodynamic Brakes ...... 3-161
ix LIST OF TABLES
Table Page
Table 2-1 Failure Mode Severity Categories...... 2-12
Table 3-1 Measured AEM-7/Amcoach Train Stopping Distances ...... 3-5
Table 3-2 Amtrack Metroliner FMEA Worksheet ...... 3-7
Table 3-3 Brake Types on X2000 Trainset...... 3-15
Table 3-4 X2000 Automatic Brake System Pressures for Amtrak Demonstrations . 3-22
Table 3-5 Specified X2000 Train Stopping Distances from Different Speeds .... 3-22
Table 3-6 Measured X20G0 Train Stopping Distances, Full Service Braking, U.S. Demonstration Tests ...... 3-24
Table 3-7 X2000 FMEA Worksheet ...... 3-29
Table 3-8 Calculated Braking Distances for the ICE/USA Demonstration Train...... 3-45
Table 3-9 ICE FMEA Worksheet ...... 3-47
Table 3-10 TGV-A Trainset Stopping Distances for TypicalConditions...... 3-55
Table 3-11 TGV FMEA Worksheet...... 3-58
Table 3-12 Intercity 225 FMEA Worksheet...... , ...... 3-91
Table 3-13 Braking System Design Overview for Shinkansen Trainsets...... 3-104
Table 3-14 Nominal Braking Rates for Shinkansen Trainsets...... 3-104
Table 3-15 Shinkansen 200 FMEA Worksheet...... 3-108
Table 3-16 Shinkansen 300 FMEA Worksheet...... 3-113
Table 3-17 Transrapid TR07 FMEA Worksheet ...... 3-137
Table 3-18 HS ST FMEA Worksheet...... 3-148
Table 3-19 Braking Strategy of the MLU002N...... 3-152
Table 3-20 MLV002N FMEA Worksheet...... 3-165
x 1. INTRODUCTION
With the passage of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), there is renewed interest in establishing high-speed guided ground transportation (HSGGT) service in some of the major transportation corridors in the U.S. These initiatives have ranged from traditional (though upgraded) rail service to the advanced technologies such as magnetically levitated (maglev) trains. As part of a comprehensive review of the safety and reliability of the proposed HSGGT systems, this current study of advanced braking systems examines the various strategies used to brake these high-speed vehicles safely, reliably, and efficiently.
Conventional methods for braking rail passenger vehicles operating at “moderate” speeds (<200 km/h, 125 mph) include friction brake systems, either wheel tread or disc brakes, and dynamic brake systems, both converting the train’s kinetic energy into heat. In modem transit or intercity trains, these brake systems are “blended” to achieve the desired deceleration rates for ride comfort, efficient train handling, and safety under both service and emergency conditions. As operating speeds increase above 200 km/h (125 mph), the capacity of these conventional brake systems is taxed and other methods of slowing the train must be used, especially during emergency braking situations. With other technologies such as maglev, unconventional brake systems such as reversed thrust of a linear induction motor (LIM) or aerodynamic braking become the “norm” in lieu of friction braking.
The objective of this study is to develop qualitative and quantitative information on various braking systems for HSGGT systems identified by the VNTSC as potential candidates for use in the U.S. These data encompass system safety considerations as well as the technical information describing the braking systems. This information provides sufficient detail to assess the technical and economic feasibility for U.S. applications and to assist the FRA in future rulemaking activities related to high-speed braking of these HSGGT systems.
1-1/1-2 2. BACKGROUND
2.1 TECHNICAL DESCRIPTION OF BRAKING SYSTEMS
The purpose of this task is to develop detailed technical descriptions of each existing and proposed HSGGT braking system, both foreign and domestic. These descriptions include detailed information in the following broad categories:
• Braking system physical capabilities for both normal service and emergency braking,
• Braking system effects on vehicle, guideway, and other infrastructural components,
• Braking system control and safety features, including control integration, ergonomics, operational status, diagnostics, redundancy, testing, inspection, and maintenance.
Train brake systems must meet three primary criteria in their design, operation, and maintenance:
• Fail-safe characteristics, both on a component and a system level,
• Reliability and redundancy in components and control paths, and,
• Braking capacity to stop the train within the controlled block under the most adverse conditions.
Train braking systems for both freight and passenger service have been developed over the years as an integral part of the train control system, which includes signaling, dispatching, and (in recent years) automatic train control. Since its invention by George Westinghouse in the latter part of the 19th century, compressed air train brake systems have dominated in North American practice. The straight air brake, the original form of the Westinghouse design (1869), uses compressed air from the main reservoir supply through direct piping to the brake cylinders to produce the braking effort. With a loss of air pressure (a train separation, for example), brakes could not be applied. The automatic air brake (1872), the form common in service today, is designed to apply the brakes when air escapes from the system. In this way, the automatic air brake is more inherently a fail-safe system.
A competitive vacuum brake system was developed and is still used by some overseas railroads. In this system, braking effort is produced by exhausting air from the brake cylinders by an ejector on the locomotive. Effective pressures are limited in the vacuum system, where cylinder sizes are large and braking forces relatively low. Electro-hydraulic brake systems are also used in some applications, primarily on urban rail transit vehicles.
2-1 In the automatic air brake system, each car in the train has auxiliary and emergency air reservoirs which are charged from the main (locomotive) reservoir through the train’s main reservoir pipe and/or the train’s brake pipe to release the brakes. In freight service, a single pipe (the brake pipe) is used for both charging and control functions. A “triple valve” connected to the brake pipe and reservoirs directs air to the brake cylinder when air pressure is reduced in the brake pipe below that in the auxiliary reservoir, setting the brakes. This reduction in brake pipe pressure is produced by setting the locomotive brake valve into the “service” (or the emergency) position, or by a break in an air hose or pipe. Most modern passenger equipment is “two-pipe” (Figure 2-1), charging the system through the main reservoir pipe and controlling through the brake pipe pressure.*
The need for high braking effort to assure the shortest stopping distances from high speeds led to the development of special brake equipment for high-speed passenger trains. Friction coefficients of metal brake shoes are reduced substantially at higher speeds. Greater brake cylinder pressures and shoe (or pad) forces may therefore be applied at higher speeds without danger of sliding the wheels. Higher brake pipe pressures were used in passenger service with the standard quick-action equipment and the addition of a high-speed reducing valve at the cylinders. Modem brake systems have speed governor control of pressure so that brake shoe force is reduced as speed decreases. This is accomplished by modulating brake cylinder pressures or switching to a smaller-diameter brake cylinder when the speed drops below a given level. In recent years, composition brake shoes or pads have been used in passenger service to provide more uniform friction coefficients over a wide range of speeds.
The Universal Control (UC) brake for passenger service was one of several designs evolved to address the more severe passenger train operating conditions. The use of control and relay valves on each car provided better response to differential pressures than the “triple valve” and allowed graduated release, rather than direct release, of brakes for better train control. The electro-pneumatic passenger brake was a next step in passenger train control sophistication. This system includes electro-pneumatic transmission of brake application and release which reduces the serial action time of a purely pneumatic system to nearly zero, eliminating longitudinal draft gear action and “surge.” A typical schematic is shown in Figure 2-2.
Friction braking systems for passenger trains include axle disc brakes and/or wheel tread brakes. In high speed service, friction brakes are subjected to extreme thermal and mechanical stresses. Because of this, substantial research and development has gone into improvements in both materials and designs. For medium-speed operations (< 200 km/h, 125 mph), ventilated brake disks are used to moderate temperatures. This results in substantial power losses at high speeds. Non-ventilated alloy steel disks with sintered-metal pads have been used as an alternative on some equipment.
The European standard UIC Code 546 OR, "High Power Brakes for Passenger Trains," 1-1-80, states under general conditions to be fulfilled that brakes for passenger trains "must only require a single pipe for its operation."
2-2 Figure 2-1. Schematic of Typical Automatic Air Brake System (Ref. 1)
2-3 1 BRAKE DRIVER AND BATTERY VALVE INTERLOCK SUPPLY
MAIN RESERVOIR PIPE
J B R A K E P IP E
J APPLICATION WIRE
J RELEASE WIRE
J COMMON WIRE J
( PNEUMATIC EQUIPMENT
TO BRAKE CYLINDER ------I ------TO BRAKE CYLINDER
Figure 2-2. Schematic of Typical Electro-Pneumatic Brake System (Ref. 1)
2-4 Wheel slip control is also included in modem systems to modulate braking effort as adhesion limits are reached or exceeded. Adhesion is the fundamental limit of the combined friction and dynamic braking capability of a given wheelset. This limit is affected by a number of factors, including truck design (unsprung mass, primary suspension characteristics, load equalization, wheel/rail contact geometry, to cite just a few), vehicle weight, and train speed. Perhaps most importantly, adhesion is affected by rail running surface contaminants such as rain or snow, industrial pollutants, grease or oil from equipment or wayside lubricators, or even wet leaves. Published results of adhesion measurements by the French National Railways (SNCF), Figure 2-3, illustrate these effects.
A model of wheel/rail adhesion versus slip is given in Figure 2-4. The stable side of the curve, known as “creep,” includes small relative motion between wheel and rail at the contact patch without gross sliding. The unstable side of the curve leads to gross sliding and a locked wheelset, high surface temperatures, and the formation of wheel flats. To avoid this, brake cylinder pressure must be modulated rapidly to reduce braking torque on the wheelset. The selection of adhesion values on which to base brake system capabilities or signal block distances is generally more a matter of conservative empiricism than measurement. Signal distances are set according to curves relating distance to speed, gradient, and other local conditions for specific trainsets. A typical curve is shown in Figure 2-5 based on tests by the British Railways research department.
Friction brake systems are supplemented by dynamic (resistive) or regenerative braking, where the traction motors of the locomotives or powered cars are used as generators to convert train kinetic energy into electrical energy. In dynamic braking, the electrical energy is converted to heat in resistor banks and dissipated into the surroundings; while in regenerative braking, the electrical energy is returned to the power grid through third rail or catenary. Generally, greater braking power is available from regenerative systems. If the power system “rejects” the load, however, the regenerative braking is inoperable. High-speed diesel-electric or turbine-electric locomotives would use the dynamic (resistive) braking alternative.
Other auxiliary systems are used on high-speed trains for braking in service or emergency situations. These include magnetic track brakes which dissipate kinetic energy through friction to the rails, and eddy current track brakes which dissipate kinetic energy through eddy currents in the rails or track structure. The magnetic track brake uses electro-magnets to attract itself to the rail head, dissipating energy through sliding friction between the rail and a wear plate. This technology was developed in the 1930s for use with street cars, mainly for emergency braking. The braking effort available is several times higher at low speeds than at high speeds. Eddy current brakes are suspended about 7 mm above the rail head. When energized from a secure battery backed-up power source, the electro-magnets induce eddy currents in the rail with resulting braking effort. The performance characteristic of the brake is almost speed independent between 200 km/h and 50 to 70 km/h as shown in Figure 2-6. While these auxiliary brakes can reduce wear and maintenance on the friction brake system and are less affected by adhesion limits, they can have adverse effects on rail wear, rail temperature (and possibly track lateral stability), and, due to induced electromagnetic interference (EMI), on track signalling and control circuits.
2-5 (T) Dry rail - upper limit Coefficient of adhesion ® D r y rafl - m o s t frequent up p e r limit
.25- < D D a m p rail - m o s t frequent up p e r limit
(?) D a m p rail - lower limit
(§) Wet leaves
. 2 0 - - 9 5 % of aU measured points
.15-
.10
.05
1 0 2 0 3 0 4 0 5 0 6 0 7 0 M P H S p e e d
Figure 2-3. Coefficient of Adhesion Versus Speed for Tread Braked Vehicles (Ref. 2)
2-6 Figure 2-4. Typical Relationship Between Adhesion and Wheel Slip (Ref. 3)
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Figure 2-5. Graph of Braking Performance of BR Intercity 125 Train (Ref. 3) Figure BRAKE FORCE (KM) 2-6. Braking forDiagram TrainICE Showing Current Eddy Braking Effort (Ref. 4) 2-9 Aerodynamic drag brakes have also been considered for some of the higher speed operations, particularly the maglev systems. Different HSGGT system designers have used different combinations of these systems, blended over the speed regime to provide the designer’s best choice of characteristics. In the newer systems, braking functions are computer controlled through the use of a central computer and individual brake system microprocessors to provide efficient, repeatable, comfortable, and (above all) safe stopping distances.
2.2 SYSTEM SAFETY ANALYSIS
The system safety analysis of the high speed rail braking systems is a high-level examination of system failure modes to identify the inherent protection included in the system designs. In general, the failure modes for each trainset are established at a subsystem level for two reasons. First, this level of detail is sufficient for the purposes of this study and second, the available information is insufficient to allow a more detailed examination.
As an example, a braking control system may be considered as a single unit with failure modes described as "fails such that too little braking is commanded" or "fails such that too much braking is commanded". A detailed evaluation of the control system would be required to establish the specific conditions that would lead to these control system failures (or even if those failure modes are possible in some cases). However, examining the system's response to this postulated failure mode can identify the inherent protection (or lack of inherent protection) for the failure mode. This type of result is believed adequate for the purposes of establishing regulatory priorities.
Approach. The system safety analysis used a modified Failure Modes and Effects Analysis (FMEA) approach to identifying important system failure modes. The modifications provide for reporting inherent protection provided by the system design and an indication of the fault- tolerance and fail-safety of each identified failure mode.
The procedure used for identifying failure modes generally followed the logical operation of the braking system strategy and concepts. Failure modes were postulated for each element of the braking system from initiation through application of the braking method. This deliberate, systematic approach to identifying failure modes helps reduce the possibility of omissions in the failure mode list. For each failure mode, the immediate and expected effects (outcomes) of the postulated failure mode were estimated as well as the response of on-board sensors or other equipment, where appropriate. Thus, for each failure mode and effect, the specific design features that mitigate or protect against potential loss of braking capability can be identified by examining the failure mode, effects, and system response.
In addition to the failure modes identified through the above procedure, each braking system was evaluated for the following specific failure modes.
• complete loss of power to the electrical portion of the braking system, • loss of stored energy (e.g., air pressure) required to apply braking, and • train operator incapacitated.
2-10 Failure Mode Significance. The significance of the failure modes identified in the safety analysis are described in two ways. First, each failure mode was assessed to determine if it was fault tolerant or fail safe, according to the analysis working definitions presented below. Second, if a failure mode was judged to be not fail safe, the failure mode was examined to determine the severity of the failure mode as described below. These two factors determine the importance of the failure mode in the safety analysis results.
Working Definitions. The two key definitions employed in the safety analysis are based on the concepts of fault tolerant and fail safe.
• Fault Tolerant is defined as the built-in capability of a system to provide continued (full or limited) operation in the presence of a limited number of faults or failures. As applied in the safety analysis, continued operation means continued train operation with most braking capability intact and, in the absence of subsequent failures, continued train operation does not result in an immediate or subsequent hazard to train operations, passengers, or significant equipment damage.
• Fail Safe is defined as a characteristic of a system or its elements whereby any;- failure or malfunction affecting safety will cause the system to revert to a state".. that is known to be safe. As applied in the safety analysis, system failing in a safe condition means failures in the brake system such that the train results in a safe condition. Safe condition means the train will come to a full stop without loss of human life, injury to persons, major loss of equipment, or any combination of the three; or full brake capability is retained without additional operator action required to initiate braking. Thus by definition, operator backup for the braking system is not a fail safe condition. This approach permits identification of the operator's contribution to recovering the braking function in:;: the event of failure through the use of severity codes, as described below.
Failure Mode Severity. Since the above definition of fail safe permits a number of failure modes to be designated as not fail safe, the failure mode severity scale shown in Table 2-1 was employed to distinguish among those failures. These severity codes distinguish between three types of failures that are defined as not fail safe.
• Failure modes that result in loss of train-wide braking capability with no means of recovery (codes A1 and Bl).
• Failure modes that results in loss of train-wide braking Capability, but is recoverable through direct operator action or control (codes A2 and B2).
• Failures modes that result in loss of local braking capability (an axle, a truck, or a car) (codes A3 and B3).
Failure modes that were defined as fail safe, whether they are fault tolerant or not, are considered as having lesser severity.
2-11 Table 2-1. Failure Mode Severity Categories
Fault Fail Tolerant Safe Severity Description No No A1 A failure that results in an immediate hazard potentially leading to a catastrophic condition. A2 A failure that results in a subsequent hazard, but is recoverable to a safe condition by operator action. A3 A failure that results in a subsequent hazard potentially leading to an unsafe condition over time if not corrected. Yes No B1 A permitted or unannounced failure potentially leading to a catastrophic condition. B2 A permitted or unannounced failure that results in reduced braking capability, but is operator-recoverable to a safe condition. B3 A permitted or unannounced failure that results in reduced, but sufficient, braking capability. No Yes C A failure that represents a subsequent hazard, however the system remains in a safe condition. Yes Yes D A failure that represents no significant hazard and results in a safe condition.
The following sections present the results of the system safety analyses for each of the high speed rail and maglev trainsets included in this study. The modified failure modes and effects analysis results tables are presented immediately after the technical discussion of the braking system. The tables identify the failure mode significance in terms of fault tolerance and fail safety and the failure mode severity in terms of the above severity codes.
2.3 CURRENT REGULATIONS
In the United States, railroad brake systems must comply with the Code of Federal Regulations (CFR) as stated in 49 CFR Ch. II Part 232 - Railroad Power Brakes and Drawbars. The salient features of this regulation are as follows:
• Not less than 85 percent of the cars of a train shall have their power brakes used and operated by the engineer (driver) of the locomotive.
♦ It must be verified that brake equipment is in an operative, safe, and suitable condition for service.
2-12 • Each train must be inspected and tested prior to each service use, and a running brake test must be made as soon as train speed permits.
• Emergency braking will always be available no matter what the existing state of the braking system cycle (for example, in service application, or in release). The brake system will function to release an emergency application with the same certainty as a service application.
• Brake equipment must be cleaned, repaired, lubricated and tested within the requirements of the Association of American Railroads (AAR) Standard S-045 in the Manual of Standards and Practices of the AAR.
These requirements, along with Other standards of the Association of American Railroads, operational preferences of Amtrak and other potential operating authorities, as well as the requirements and preferences of train operating employees and unions, must be taken into consideration in adapting foreign trainset braking systems to U.S. applications.
2-13/2-14 3. TECHNICAL DESCRIPTION OF BRAKING SYSTEMS
3.1 AMTRAK METROLINER SERVICE (NORTHEAST CORRIDOR)
3.1.1 General Description of Trainset
The Amtrak Metroliner service on the Northeast Corridor between New York City and Washington, D.C. represents the state-of-the-art in U.S. high-speed rail service. On portions of this route, the Metroliner trains achieve speeds of 201 km/h (125 mph) on a concrete-tie track structure with continuous welded rail (CWR) and direct fixation fasteners. These trains consist in general of an AEM-7 electric locomotive and six Amcoach passenger cars. Express Metroliners with one intermediate stop complete the 362 km (224-mile) trip from Washington to New York in 2 hours 30 minutes. Longer trains are also run with tandem AEM-7s, achieving the 201 km/h maximum speed, but with longer overall schedule times.
The AEM-7 locomotive is based on the standard ASEA Rc-4 locomotive used by the Swedish Railways (SJ). Built by Electro-Motive Division (EMD/GM) with electrical equipment by ASEA (now ABB), the 52 locomotives have been in service since 1980. These 4-axle units, rated at up to 5400 hp (7600 hp short term), have solid-state rectifiers and thyristor control of individual wheelset traction motors to control adhesion and wheel slip. The units run off an 11,000 volt, 25 Hz ac overhead catenary power source.
The original Amfleet coaches were some of the last constructed by the Budd Company and use the standard Pioneer III truck design. Introduced during the late 1970s as the self- powered Budd Metroliner cars were phased out, the design incorporates many of the features of the these older self-powered units. A second procurement, the Amfleet II car, was constructed during 1982. The full trainset (one locomotive and six passenger cars) weighs approximately 366 metric tons (404 tons).
3.1.2 Braking System Design
The braking system of Amtrak’s Metroliner trains represents a proven, standard design for an electric locomotive and locomotive-pulled passenger cars operating in a manual block signal system with in-cab signal indications. The braking system on the AEM-7 locomotive consists of dynamic (resistive) brakes, and pneumatically-powered tread and disc brakes (Ref. 5). The coaches are braked by pneumatically-powered axle-mounted disc brakes. The major components of this system are described in the following section.
Major Braking Components
Air Compressor. A single stage, positive displacement rotary (screw-type) air compressor supplies the automatic air brake system of the train. This unit is driven by a 440-volt three- phase electric motor. Output air is filtered and dried, then supplied to; the main reservoir.
Dynamic/Resistive Brake. The AEM-7 locomotive uses resistive dynamic braking, where kinetic energy is converted back to electrical energy by the traction motors, then dissipated to
3-1 the atmosphere as heat through a bank of resistors mounted on the car body roof. Cooling is provided simply by air flow across the resistor bank from forward motion. Dynamic braking capacity is a function of train speed, as shown in Figure 3-1. For typical braking adhesion limits at higher speeds of 0.10 (wet rail) to 0.13 (dry rail), dynamic braking can range from 30 to 39 percent of the available limit at 200 km/h (125 mph), and from 52 to 68 percent of the available limit at 130 km/h (80 mph). A limit of 970 amps is imposed so that the traction motors are not damaged. Below 60 km/h (37 mph), dynamic braking capacity decreases sharply as motor armature speed decreases.
Air Activated Disc Brakes. The AEM-7 locomotive and passenger cars are equipped with conventional automatic air brakes. This provides fail-safe braking and high levels of retardation. On the locomotive, the disc brake units are located on the outboard end of each truck and consist of two discs bolted to one another through the wheel plate. A pair of calipers with brake pads clamp around the wheel rim onto the two discs to provide braking. The discs contribute between 60 to 80 percent of locomotive friction braking.
The Amcoach cars have two ventilated brake discs per axle with standard brake calipers and composition pads. In addition, two wheel tread brakes are used to provide a portion of the friction braking and to “condition” the wheel treads (to reduce surface contaminants, improving adhesion).
Tread Brakes. On the locomotive, single shoe tread brakes are located at the inboard side of each wheel. These units use cast iron brake shoes to provide the remaining 20 to 40 percent of the friction braking effort and also clean and condition the wheel treads for improved adhesion. As noted above, the passenger coaches also use tread brakes to improve wheel/rail adhesion.
Parking Brake. Standard AAR-approved handbrakes are used on the locomotive and cars. These are configured so that 100-125 lb applied to the handbrake rim will set the brakes to hold the car on a 5 percent grade. Brakes are applied to both axles of one truck.
Braking Control Components
The automatic air brake system on the Metroliner trains consists of a number of subsystems on the locomotive and cars that are optimized to produce smooth and repetitive stops. This is accomplished with the standard Type 26 two-pipe brake system shown in schematic in Figure 2-1. An outline drawing of a typical Type 26 pneumatic system is shown in Figure 3-2.
Locomotive Brake Control Valves. Brake controls in the cab of an AEM-7 locomotive consist of the following components: 1) the automatic brake valve, which commands braking of both locomotive and train brakes through reduction in the train brake pipe pressure, 2) the independent brake valve, which controls only the locomotive brakes, 3) an automatic brake valve cutout valve, 4) an independent and automatic brake cutout cock, and 5) an emergency brake valve. The Type 26 brake control valve is “pressure maintaining” and will hold the desired brake pipe pressure reduction steady against normal system leakages. The independent brake valve is self-lapping and will hold the locomotive brakes in the applied setting.
3-2 SPEED. U / l
0 32 64 97 IPS 162 194 227 BRAKING EFFORT,kN BRAKING
S o u r c e : R e f e r e n c e 1 .
Figure 3-1. Dynamic Braking Performance of the AEM-7 Locomotive (Ref. 5)
3-3 1 . NYAB BRAKE PIPE HOSE 2 . BALL-TYPE GRIPSEAL ANGLE COCK 3. EMERGENCY BRAKE VALVE 4. BRAKE APPLICATION VALVE S. AUXILIARY AIR SUPPLY RESERVOIR & UNIRACK MANIFOLD 7. WATER-RAISING RESERVOIR 8. MAIN RESERVOIR 9. PNEUMATIC BRAKE ACTUATOR/CALIPER ASSEMBLY 10. TWO-PIECE AXLE MOUNTED DISC ASSEMBLY 11. WHEELSUDE SYSTEM 12. ADJUSTABLE REDUCING VALVE 13. REDUCTION RELAY VALVE 14. WHEELSLIDE DUMP VALVE AND RESERVOIR 15. CONTROL/SELECTOR VOLUME
w I ■P-
Figure 3-2. Typical U.S. Passenger Train Pneumatic Brake System (Ref. 1) In addition to the pneumatic brake controls, the locomotive has a dynamic brake control. The dynamic brake is controlled directly by the throttle: forward through ten positions applies traction power, and pulling the throttle toward you past the zero position applies dynamic braking. The dynamic braking is also controlled by the automatic brake valve and is blended with the pneumatic braking, using the dynamic braking to maximum strength, supplemented by friction braking as required. Applying the automatic air brakes disengages throttle power if it is in one of the power positions.
Passenger Car Brake System. The standard Type 26 brake system on the cars consists of a main reservoir pipe supplying air to the main pneumatic control unit panel and air supply reservoirs, and a brake pipe providing the basic braking control signal (pressure modulation for brake application or release). A reduction relay valve at the opposite end of the car speeds the brake application action. Pressure to the brake cylinders is modulated by the wheelslip dump valve to avoid loss of adhesion. A wheel slip protection system, a WABCO E-5 Decelostat unit, is used to control these valves. A 100-pulse per revolution angular velocity signal from each axle (a gear tooth and magnetic pickup) is analyzed by logic circuits to detect wheel slip. This circuit compares the tachometer signals from the four axles and detects a speed differential (> 2 mph) of the slipping wheelset, reducing brake cylinder pressure at that truck. It also compares the difference in rate of change of rotation speed as the car decelerates in braking. The cars as originally delivered had electro-pneumatic control assist, but this has since been removed. Three emergency brake valves and associated brake application valves are located on the car for train crew or passenger use in emergencies.
3.1.3 Braking System Performance
Brake test stopping distances for the AEM-7 and Amcoach trainset are listed in Reference 5 as follows in Table 3-1:
Table 3-1. Measured AEM-7/Amcoach Train Stopping Distances
Braking Mode 194 km/h (120 mph) Full Service (friction brakes only) < 1.95 km (6400 ft) > 2.7 km/h/s (> 1.7 mph/s) Full Service (friction plus dynamic brakes) < 1.80 km (5900 ft) > 2.9 km/h/s (> 1.8 mph/s) Emergency (friction brakes only) < 1.49 km (4900 ft) > 3.5 km/h/s (> 2.2 mph/s)
There are currently no computer-based train brake diagnostic features on the AEM-7 and Amfleet trains. The brake system is monitored in the time-honored way by observing brake pipe pressure.
3-5 Since the trainset does not use any novel braking methods, any effects on the infrastructure are those that have been experienced for years by railway authorities running medium-high speed passenger trains.
3-6 Table 3-2. Amtrak Metrollner F M E A Worksheet FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No S = Failure Mode Severity, described in Section 2.2
Amtrak Metrollner—Northeast Corridor Service (USA) Page 1 of 6
C o m p o n e n t Failure M ode Effect on Braking Subsystem Effect on O verall Braking System How Detected/Response FT FS S
Automatic Brake Valve F a i l s o n . Braking occurs above desired Braking occurs above desired level Operator notified via system N Y 1 C
level for the trainset, specifically for the trainset, specifically full monitoring. M ust decrease level of
full brakes. b r a k e s . braking, if possible, or train stops.
F a i l s o f f . Braking is under desired level, Braking is under desired level, Operator notified via system N N A 2 specifically no braking available specifically no braking available for monitoring. M ust increase level of for the trainset via this valve. the trainset via this valve. braking, which m ay include using emergency brakes.
Brake Control Unit Signal for too much Braking occurs above desired Rapid decrease in speed beyond level Assume operator has indication of N Y 1 C (BCU ) (Includes b r a k i n g . level for the trainset. d e s ir e d braking level and BCU status. electropneum atic valves, Braking effort is too high resulting pressure transducers, in rapid speed decrease. Reduce relay valve) Assume one level of braking requested or train BCU per locomotive. s t o p s .
Signal for too little Braking is under desired level Braking is under desired level for the Assume operator has indication of N N A 2 b r a k i n g . for the trainset. t r a in s e t . braking level and BC U status. Train does not slow quickly
enough. M ust increase level of braking requested, probably via
emergency brakes.
No signal for braking Braking does not occur at all for Braking does not occur at all for the Assum e operator has indication of N N A 2 when braking the trainset. t r a in s e t . braking level and BC U status.
r e q u e s t e d . Train does not slow down. Must
utilize em ergency brake.
Rheostatic Brake Fails indicating Tw o stage relay valve holds off Friction braking is too low resulting Assume operator is notified of low N N A 2 Control Unit (Assume higher than actual m ore friction braking than it in increased stopping distances. braking level. Train does not slow one per locom otive) rheostatic braking should given the actual quickly enough. M ust increase
e f f o r t . rheostatic braking level. level of braking requested, possibly via em ergency brakes. Table 3-2. Amtrak Metroliner F M E A Worksheet (cont.)
FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No S = Failure Mode Severity, described in Section 2.2
Amtrak Metroliner—Northeast Corridor Service (USA) Page 2 of 6
C o m p o n e n t Failure M ode Effect on Braking Subsystem Effect on O verall Braking System How Detected/Response FT FS S
Rheostatic Brake Fails indicating low er Tw o stage relay valve does not Friction braking is higher than Assum e operator is notified of N Y 1 C
Control Unit (Assume than actual rheostatic hold off enough friction braking required . W heelset Slip Protection braking effort level. Braking effort one per locom otive) braking effort. given the actual rheostatic may be overworked as a result. is too high resulting in rapid speed braking level. This results in decrease. Reduce level of braking
too m uch friction braking being r e q u e s t e d . applied for the actual rheostatic
braking level.
System monitoring Loss of any signal Full brakes applied by system. Full brakes applied by system . If system loses signal, N Y c transmitted to system autom atically applies brakes.
m onitoring.
W heelset Slip Protection Fails with output Results in m aintaining current Over application of brakes on one W heelslide indicated to driver. N N A 3
Control (includes speed failing to m odulate brake level, not alleviating wheelset causing w heel slide for the Assum e driver can isolate system sensor) Assume it the brake cylinder w heel slip. Braking applied to w h e e l s e t . and continue at reduced speed or operates on individual p r e s s u r e . wheelset is above desired line speed depending on degree of w h e e ls e ts . braking level resulting in wheel f a il u r e . slip. This causes excessive
wear on wheels and rails.
Fails with output Braking applied to wheelset is Reduces available braking by the Assum e operator receives Y N B 3
requesting brake below desired braking level effort of one wheelset. indication o f low er braking effort
cylinder pressure to resulting in reduced or no than requested. M ay have to be vented, thus braking for the wheelset operate at reduced speed or line
keeping the valve associated with the failed speed depending on degree of o p e n . c o n t r o l. f a il u r e .
JOieoatatle Stoking4
M otor Truck
Catenary Power Loss of power or Assume battery back up power Battery supplies power and rheostatic Assum e driver has indicators on Y Y D decrease in power. is available and initiates. braking is still available. catenary and battery status and that
the battery autom atically initiates upon catenary pow er loss. Table 3-2. Amtrak Metroliner F M E A Worksheet (cont.)
FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No S = Failure Mode Severity, described in Section 2.2
Amtrak Metroliner—Northeast Corridor Service (USA) Page 3 of 6
C o m p o n e n t Failure M ode Effect on Braking Subsystem Effect on O verall Braking System How Detected/Response FT FS S
B a t t e r y Loss of power or No effect if catenary available. No effect if catenary available. Assum e driver has indicators on Y Y D decrease in power. There w ill be no backup power Friction brakes capable o f stopping battery status. Repair at first
for dynam ic braking for the tr a in . m aintenance opportunity. track with the failed battery s y s t e m .
Traction M otor (Assume D o e s n o t Loss of or decrease in rheostatic Relay valve will allow m ore or all of Relay valve reacts to low er Y Y D two per track.) accept/produce braking for the m otor track. requested braking effort to be friction rheostatic braking by allowing
current to dissipate in b r a k in g . m ore friction braking. resistor grids.
Bearing failure, axle Unintentional w heel slide for Unintentional wheel slide for the W SP monitored by driver. Failure N N A 2 s e iz e s . the m otor track. W SP attempts motor track. W SP attempts to of m otor, assum e driver can isolate to alleviate w heel slide. alleviate wheel slide. the w heelset and continue and low er speed or line speed.
Resistor Grids Inability to dissipate Loss of or decrease in rheostatic Assume relay valve will allow m ore Relay valve reacts to lower Y Y D energy/heat braking for the m otor track. or all of requested braking effort to rheostatic braking by allowing be friction braking. m ore friction braking.
Friction Braking
M otor Track
Air Brake Pipe (ABP) Fails with Low Brakes applied. A ll brakes applied to degree o f low Speed reduction. Com puter notifies N Y l C P r e s s u r e pressure failure. operator of low pressure. (Effects entire brake
s y s t e m )
Relay Valve Signal for too m uch Braking occurs above desired Rapid decrease in speed beyond level Operator notified via system ' N Y C b r a k in g level for the truck. desired. W heel slide protection monitoring. M ust decrease level of prevents wheelslide and m aintains b r a k i n g .
braking. Extra wear on brake components and overheating may
r e s u lt .
Relay Valve Signal for too little Braking is under desired level Braking effort is too low , increasing Operator notified via system Y N B 2 b r a k in g . for the track. stopping distance. monitoring. M ust increase level of b r a k i n g . A 2 S A 3 B 3 A 3 B 3 D C N FS N N N N Y Y N FT N N Y Y Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Operator notified via system Operator notified via system How Detected/Response monitoring.em ergency M ay needbraking. to utilize isolate axleand wcontinue ith failedr e q u irwithin e dactuator . speed lim its Assume operator can continue at safety pressure relief valve is and continuer e q u irwithin e d . speed limits Operator notified via system monitoring. Assume operator can System monitoringbraking effort indicates thanreduced requested.lower speed. available on reservoir. System m onitoringAssume indicates operator reducedlower canspeed. continueSystem at monitoringoperator of andnotifies comreservoir pressor pressure. running Assume operator of com pressor running monitoring.isolate Assume axle withoperator failed can actuator braking effort than requested. System monitoringand notifies reservoir pressure. Effect on OverallBraking Braking does not System occur at all forOne the actuator/disc,constantly brake applied effort equivalenton is disc and to calipers and brake t m c k . effort from one disc.overheating Excessive is possible.wear One actuator/disc,applied, brakelostequivalent braking effort tonotcapability effort from Brakeone disc. effort constantly applied to one wheel. Excessive wear on Brake effort not applied, lost brake Friction brakesonce applied.cannot be released brakes andp o soverheating s i b le . of brakes is effort capabilityof one equivalentwheel. to effort and continues beyond norm al levels. Pressure builds in the m ain reservoir Effect on BrakingBraking Subsystem does not occur at all forOne actuator/disc, brakeeffort effort fromwear isone on disc.disc Excessiveand calipers and One actuator/disc, brakecapability effort equivalent to effortBrake effort constantly applied t h e t r u c k . constantly applied equivalent to not applied, lost brakingfrom one disc. to One wheel.on brakes Excessive and overheating wear of Brake effort not applied, lostw h e e l. brakes overheatingp o s s i b l e . of brakes is brakes is possible. brake effortequivalent capability to effort of one reservoir and continues beyond M ay not be able to recharge Pressure builds in normthe m al ain levels. brake system. Table 3-2. Amtrak FTable3-2. Metroliner M E AWorksheet (cont.) when braking Fail disc brakes on No signal for brakingr e q u e s t e d . F a i l o f f Fail disc brakes off F a i l o n Failure M ode F a i l s o n F a i l s o f f Amtrak Metroliner—NortheastC o m p o n e n t Corridor Service (USA) Page 4 of 6 Disc BrakeD isc, Actuator, and discs/axle)Calipers (2 Relay Valve w h e e l) Compressor (1) Tread BrakeTread Actuator, Brakeindependently (Acts on each
3-10 D C A 3 D S C A 3 C Page 5 of 6 N Y Y Y Y FS N Y N Y Y N N N N FT S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT M aintenance and inspection M aintenancec h e c kand s . inspection Assum e operatorof pressure is notified level inin Mcab RP. Inspectiondetect and maintenancevalve failure. should Repair at first c h e c k s . Gauges in cab indicatedriver lowhas operationindicator in o fcab com also. pressor How Detected/ResponseAssum e operatorrelief valve isCom notified operates pressor and autom(s) can atically. be Systemshut off monitoringto com indicates pressortries low operation. to achieve Compressor desired pressure. m aintenance opportunity. prevent further pressure buildpressure up. of reservoir and pressure of reservoir. Assume Friction brakes m ay not be released Air is vented from m ain reservoir No effect. This requires a second contamination. contam ination and possible line if insufficient pressure is in M RP. Assume pressureavailable relief on m valve ain reservoir. is Friction brakesonce applied.cannot be released resulting inreservoir. low pressure excessive Friction in m running ainbrakes ofapplied compressors or failureor forim this p a c t. failure to have any W ear on components. System W ear on components.b lo c k a g System e s . Effect on O verall Braking System both w ill result. M RP so that once the friction o f the pressureMRP. deficiency in the safety valve failing closed Contam inationcorrosion and possibleof components. Pressure is not availablebrakes toare be applied, able to they be mreleased ay not because M ay not be able to recharge A ir is ventedreservoir from resulting main Frictionin low brakes applied. No effect.M R S If overpressurization a combinationoccurs, of and there for overpressurization.would be noW earrelief on components. W ear on Particulatescomponents. or grit into system. High pressure builds in main pressure in m ain reservoir. Effect on Braking Subsystemr e s e r v o ir . brake system. Table 3-2. Amtrak FTable3-2. Metroliner M E AWorksheet (cont.) sufficiently. Fails with air too wet Fails to clean air Fails with low Fails closed p r e s s u r e F a i l s o p e n Fails low pressure Fails high pressure Failure M ode M ain Reservoir Pipe A i r F ilt e r A i r D r y e r M ain ReservoirV a lv e Safety Am trak M etroliner—C o m p o n e Northeast n t Corridor Service (USA) M ain Reservoir
3-11 B 3 S A 2 A 2 Page 6 of 6 N FS N N § 1 1 1 1 Y FT N N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT How Detected/ResponseAssume system notifies operator of speed or apply em ergency braking low pressurefriction and brakingthehave lack to on ofoperate the track. at dependingdecreased M ay online the number of f a il u r e s . Em ergency brake not initiated. No brakingventing and gaugesofto theapply indicateA BP.em ergency no Crew braking notified via Assume driverof valve receives emoperation ergency notification andbraking can selectif required. valves in trailer cars. Effect on O verallFriction Braking brakes Systemunavailable for braking thefailed track reservoir. associated with the Em ergency braking not available. However, crew access to emergencyEm ergency brake not initiated. valves can be utilized. Assum e driverof valve receives emoperation ergency notification Alternately, andbraking can selectif otherrequired. em ergency vent valves m ay be operated. Effect on Braking Subsystem Pressure insufficient to apply friction brakes for the track. Em ergency braking not available. access However, to em crew ergency valvesEm ergencycan Assume brake drivernot initiated. receives be utilized. and can select em ergencyother em ergency vent valves notification o f valvebraking operation if required. Alternately, m ay be operated. Table 3-2. Amtrak F3-2. TableMetroliner M E AWorksheet (cont.) Fails with low Failure M ode Does not vent ABP. p r e s s u r e A BP not whenvented valve operated. E m ergency B4 ra k3 in 2 g 1 Am trak M etroliner—C o m p o n e Northeast n t Brake Corridor Supply(on eachReservoir Service track) (USA) Trailer Coach3 Emergency Valve Crew and EmergencyPassenger(3 Ventper TrailerValves Car) . Even though this failure results in the friction brakes being applied, this failure m ay not be failsafe if it occurs at high speeds. 1 3. Sam e as M otor Truck except the Trailer Car has two wheel tread brakes as opposed to single shoe tread brakes on each wheel for the motor car. 2. Train can be stopped safely with just friction brakes if rheostatic braking fails. 4. This section only includes modes of triggering em ergency braking because the actual application of the emergency brakes is done via the system s described above.
3-12 3.2 X2000 TILTING TRAIN
3.2.1 General Description of Trainset
There is presently a high level of interest in the potential use of active tilt train technologies to overcome the current limits for safe high speed guided ground transport (HSGGT) on existing and proposed corridors in the U.S. operating environment. The X2000 trainset is one of the technologies which has been demonstrated in the U.S. and may be procured by Amtrak for high speed operation on the Northeast Corridor. The system developer, Asea Brown Boveri Traction AB (ABB) of Sweden recently teamed with American partners Raytheon, General Dynamics, and GE Transportation Systems to pre-qualify for the Amtrak bid of 26 trainsets starting in April, 1994.
The X2000 tilting-body train has been under development in Sweden for over ten years, in cooperation with the Swedish National Railways (SJ). Revenue service operations with the train began on SJ’s Stockholm to Gothenburg line in September 1990. A limited number of trainsets are currently in revenue service on three other SJ lines. The trainset order was scheduled for completion in 1994. Two additional proposed X2000 services include Oslo to Bergen in Norway, and Helsinki to Tampere in Finland. In order to increase train speeds on existing corridors and reduce travel times without compromising ride quality, ABB has incorporated advanced (but proven) features in the trainset design:
• An active tilting-body system on the trailer cars (coaches) to improve passenger comfort in curves,
• Self-steering (radial axle) bogies to reduce wheel/rail forces and wear in curves, and,
• Asynchronous ac traction motors on the electric locomotive to reduce weight and increase reliability in traction power,
• Semi-permanent drawbar connections between all cars and locomotive (similar to transit practice),
• Integrated digital electronic controls for power, braking, communications, system diagnostics, and “hotel” functions.
The primary advantage of active-tilt technology is its ability to overcome the constraints of guideway-imposed speed restrictions by rotating the car body to minimize lateral accelerations felt by train occupants and to operate at higher cant deficiencies than would otherwise be possible through compound curves. The active tilt mechanism functions by using a bogie- mounted sensor system combined with accelerometers to constantly monitor underbalanced speed and correct for increased lateral accelerations when entering and exiting curves. A maximum tilt of 8 degrees and effective tilt angles to 6.5 degrees are accomplished by hydraulic rotation of the body of each passenger car. The power car (locomotive) itself does not have a tilting capability.
3-13 It is important to note that SJ has invested in substantial upgrading of its signal systems to ensure fail-safe operation and has also engaged in an ambitious program of upgrading its grade crossing safety devices to incorporate train occupancy circuits and full barrier protection. Higher maximum speed limits of 250 km/hr (156 mph) have been achieved in test programs conducted on SJ and the German Federal Railways (Deutsche Bundesbahn, DB) without significant negative effects on train occupants or the wheel/rail dynamics. The current limiting factors to increase speeds on SJ lines are:
« Widespread use of conventional signal and control systems; and,
• Frequency of grade crossings, type of barrier protection, and sensing devices to detect the presence of a train in a fail-safe manner
The X2000 trainset currently in service consists of a locomotive (power car), four trailer cars, and a driving trailer car (cab control car). Weights are as follows;
• Power car - 70 metric tons
• Trailer car - 54.5 metric tons
• Cab control car - 55 metric tons (5 to 6 metric tons additional ballast in winter).
Overall, the nominal train weight is 343 metric tons with a length of 340 m (459 ft). The train is designed for a maximum speed of 210 km/h (130 mph), with a revenue service speed of 200 km/h (124 mph). With a power car at each end, a maximum of 12 trailer cars may be accommodated in one train.
3.2.2 Braking System Design
The braking system of the X2000 trainset used for the NEC demonstration is described in detail in documents provided by ABB Traction Inc., New York Air Brake (NYAB) Engineering, and Amtrak [Ref. 6,7,8,9]. Major components of the brake system are described below.
Major Braking Components
The X2000 trainset which operated on the NEC during the summer of 1993 in tests and revenue service was equipped with the following brake systems. Each major subsystem can be used separately or in combination for speed retardation at those levels prescribed by route- specific requirements. Brake systems are configured differently on the power car, cab control car, and trailing cars as shown in Table 3-3. A description of each major subsystem is provided in the following sections.
3-14 Table 3-3. Brake Types on X2000 Trainset
Brake Type Power Car Cab Control Car Trailer Car Dynamic/Regenerative Brake V V Air Activated Disc Brake V V V Air Activated Tread Brake V V Parking Brake V V Magnetic (Emergency) Track Brake V V
Dynamic/Regenerative Brake. Regenerative braking is widely proven in both rail and rail transit applications. This subsystem uses the ac traction motor and propulsion system to generate a retarding force on the trainset during braking. When operable, this system can be employed across a broad spectrum of the train’s speed range. The regenerative brake on board the trainset can be used in one of two modes. It can be used as a stand-alone system to control speed or it can be used in conjunction with the friction braking system. In the blended braking mode, additional retarding force is achieved to reduce speed more rapidly.
The train driver (engineer, operator) can set the amount of regenerative braking desired through the speed controller lever (throttle) to make minor speed adjustments. The driver can also use the brake controller, which will apply the automatic train brake through the driver’s brake valve (HSM*). This action activates regenerative braking and applies air pressure to the trailing car disc brakes. When the dynamic brake limit is reached, air pressure is applied to the power car disc and tread brakes. The ratio of regenerative to friction braking is r controlled by pre-programmed blended braking regimes actuated by the central computer according to a speed profile.
Regenerative braking is a proven technique whose effectiveness is limited only by access to the power grid. Because the NEC is the only electrified HSR corridor currently operational, Amtrak has specified (pre-bid procurement document) that two trainsets must be operable in non-electrified corridors in addition to trains with electric locomotives for use in electrified territory. Non-electrified head end power would likely consist of diesel locomotives using dynamic/resistive and blended braking systems. Conventional dynamic braking systems in the U.S. use the locomotive’s traction motors to brake the train and dissipate kinetic energy through large resistive grids located above the locomotive. While dynamic/resistive brake systems are quite reliable and reduce friction brake component wear, they do not offer the additional advantage of regenerative systems by feeding part of the braking power back to the electrified power grid.
“HSM” is the German acronym for this valve.
3-15 Air Activated Disc Brake. All cars (power and trailing cars) are equipped with conventional automatic air brakes. This provides fail-safe braking and high levels of retardation. Compressed air is supplied from a Knorr Model SL-20 screw-type air compressor in the power car through the main reservoir and brake pipes to individual vehicle brake systems. The power car has wheel mounted split friction rings on all wheels serving as disc brakes. (The power car is additionally equipped with tread brakes). All trailing cars are equipped with two axle-mounted discs per axle. These are a ventilated fin design that provide cooling, but reduce the power loss at high speeds compared to the conventional vane design. Each car (including the power car) is equipped with eight SAB Type PB actuators with integral double acting slack adjusters, and associated caliper foundation rigging.
Tread Brake. The power car is equipped with tread brakes with cast iron brake shoes. These serve primarily as a wheel scrubber to increase adhesion levels and improve tractive effort and braking force. It is an SAB type BFC brake actuator integrated with single action slack adjusters configured with one unit per wheel. Amtrak states that the tread brake units provide approximately 20 percent of the friction braking force for the locomotive when working together with the rest of the friction braking system.
Parking Brake. This system is used in lieu of a conventional hand brake more common to North American equipment. Parking brakes are used on the power car and rear (inboard) track of the cab control car. The SAB Type PB cylinders are mounted two per track on the power car, working through the disc brake rigging, and on disc caliper units of the cab car. The units function with coil spring-applied force, air pressure-released. Loss of air pressure enables the spring to clamp the disc pads to ensure fail-safe functioning.
The X2000 units are activated by a magnetic release valve controlled by a switch in the operator console. In addition, the parking brake at each axle can be manually released by means of a handle. According to Amtrak, the X2000 train can be held stationary on grades up to 6 percent. Because HSR corridors are not likely to exceed these actual gradients, sufficient parking brake pressure should be achieved.
Magnetic Track Brakes. Magnetic track brakes supplied on the X2000 provide additional braking and quick response in emergency braking scenarios by achieving higher retardation rates than would otherwise be achievable with the combination of regenerative braking and conventional friction brakes. This subsystem is applied directly to the rail independent of wheel/rail adhesion characteristics in effect.
All trailer cars are equipped with four articulated magnetic track brakes. These are designed with a sealed winding located within each steel frame, where ten floating and two fixed- position cast iron shoes are bolted to the frame. The fixed shoes are located at each end of the frame and are tapered to clean away foreign objects on the rail. Each of ten interior shoes is bolted through vertical slots in the steel frame to allow for some vertical movement to compensate for changes in rail running-surface geometry. The track brake is carried approximately 50 mm (2 inches) above the rail when inactive. Track brakes are actuated by pairs of air cylinders, overcoming return-spring forces, and are electrically energized to generate a minimum 100 kN (22.5 kip) downward force on the rail. Power is supplied for
3-16 these brakes by the 24 vdc batteries on board the train. At a speed of 194 km/h (120 mph), Amtrak has estimated an average braking rate of 1.53 km/h/sec (0.95 mph/s) due to track brakes alone.
Snow Brake. The snow brake system allows the train operator to make a light application of tread braking force on the power car during adverse weather conditions. This clears the treads and brake shoes of snow or ice, and can improve wheel/rail adhesion. The snow brake function times out after one minute to prevent the tread brakes from being left on unintentionally.
Eddy Current Brake. The European version of the X2000 can be equipped with an eddy current brake. This brake is conceptually identical to the stock brakes supplied on the ICE trainset in Germany for use on Deutsche Bundesbahn (DB). Eddy current brakes operate by dispersing kinetic energy of the train via electrical eddy currents in the rail. These are non- contact brakes which reduce maintenance requirements by avoiding any contact force. Eddy current brakes can, however, cause potential rail heating problems if they are used too frequently over a given track segment.
At decelerations of up to 0.5 m/s2, 1.1 mph/s (maximum service braking with automatic train control), the train can be brought to extremely slow speeds without any mechanical contact. In low speed ranges, disc brakes are then applied to bring the train to a complete stop.
Braking Control Components
The automatic air brake system actually consists of a number of subsystems optimized to work together. This is accomplished by the following components. An overview of the pneumatic system is shown in Figure 3-3.
HSM Driver’s Brake Control Valve. The driver’s brake valve (on power and cab control cars) regulates the brake pipe pressure for application and release of disc and tread brakes. The system consists of 1) an electronic brake controller (in both cabs), 2) an HSM brake computer (power car only), and 3) an electro-pneumatic unit (power car only). The controller is activated at one or the other location by a cab switch key, and communicates by current- based signal with the central computer (one at each end of the train set), which in turn controls the HSM computer. The controller has a running position, seven detented service braking positions (Position 1 is a 0.4 bar, six psig, service reduction, Position 7 is “full service” braking reduction), and an emergency (NB) position. In the emergency position, the controller signals the HSM computer to initiate an emergency brake pipe reduction. A special set of electrical contacts de-energize an externally mounted emergency magnet valve, which pilots the emergency brake valve, which in turn vents the brake pipe quickly. This also, through the isolating valve on the pneumatic brake rack, shuts down the brake pipe relay valve cutting out the brake pipe pressure maintaining function.
The HSM computer, mounted on the electro-pneumatic unit, drives two analog converters in response to the driver’s commands for braking. One converter controls a pilot pressure to change the brake pipe pressure, while the second modulates the control line pressure (Cv) for
3-17 Main Compressor B r a k e Controllerj U c r y P
r- s S c J - { m o v } - c “}
E m e r g e n c y B r a k e 0 f l H a n d l e M R Pi p e AUXILIARY S S j f ° OPERATING UNIT Operation Val ve B r a k e Pi p e
Relay Valve
Anti Skid Valve
B r a k e Cylinders
Figure 3-3. Schematic Diagram of X2000 Train Pneumatic Brake System (Ref. 10)
3-18 power car friction brake gear. Located in the power car machine room, the electro-pneumatic unit incorporates the following equipment: 1) the analog converters, 2) the reducing valve (limiting the pressure in the pre-control reservoir of air from the main reservoir), 3) the RH2 relay valve (which incorporates the pressure maintaining feature), 4) the isolating valve (cutting out the pressure maintaining feature in emergencies), and 5) a flow indicator (monitoring main reservoir air flow to the brake pipe).
Two 50 liter air reservoirs, charged by the main reservoir pipe, supply air pressure for each of two DU 111G relay valves and the brake cylinders. Power car brake equipment is shown schematically in Figure 3-4. Electrically Controlled Emergency Valve (ECEV). The ECEV, located in the power and cab cars, consists of a normally energized magnet valve, a ' cutout cock, and a pneumatically piloted emergency brake valve. It vents the brake pipe pressure quickly when the magnet valve is de-energized by signals from 1) the HSM driver’s brake valve, 2) the alerter system (Vigilance Control), or 3) the separate emergency brake valve in the cab.
Conductor’s Emergency Valve. All trailer cars are equipped with two “conductor’s valves” which vent the train brake pipe directly to atmosphere. Activation of these valves will also signal the central computer, which will then initiate the emergency braking sequence.
KEOA/3.8/KSL-EPZ Control Valve. All cars are equipped with the Knorr Type KE control valve to provide quick response to changes in brake pipe pressure or commands from the HSM brake computer to charge, apply brakes, or release brakes on the car. This valve consists of a basic service portion, an EP brake solenoid portion, and a small (four liter) reservoir, which serves as a reference volume for the service portion. The EP brake portion, controlled by the HSM computer, consists of a brake application magnet valve and a brake release magnet valve, charging or venting the brake pipe locally for quick response. Each control valve may be isolated from the brake pipe by a cutoff cock. Each car has a 50 liter air reservoir tank charged by the main reservoir pipe. These supply air pressure to the pre control (Cv) pipe and the brake cylinders during brake application.
DU111G Relay Valves. All cars are equipped with two relay valves (“step down,” or pressure reducing), one per truck, which are piloted by the control valve and supply main reservoir air to the brake cylinders during brake application. The relay valves vent air pressure from the brake cylinders during brake release.
Anti-Skid System. The anti-skid system is designed to prevent wheel sliding during braking, which can cause wheel flats and tread thermal damage, and to maximize wheel adhesion. The system consists of a speed sensor on each axle which detects wheel slip. This signal is computer-processed to modulate brake cylinder pressure through the anti-skid valve on the affected truck. Pressure is momentarily reduced enough to restore full wheelset adhesion. The anti-skid function times out after eight seconds to prevent total loss of braking on that truck. Wheel skid is controlled by slave computers in each trailer car (which also control the tilt system and the doors).
3-19 E . Y 3 7 S E .Y 3 7 .1 I E .Y 3 7 .2 6
Antiskid brake Tread brake Track 2 E . Y 1 4 Truck 2
Figure 3-4. Schematic of Pneumatic Brake Equipment on X2000 Trainset Power Car
3-20 Brake System Operation
The X2000 braking system is designed for manual operation where the computer controls the “blended braking” sequencing during activation. Fully automatic operation is possible through automatic train control. The Vigilance Control system is used to monitor an operator-controlled train. Finally, manual override capabilities can be used to initiate full service or emergency braking.
Brake subsystems are designed for operation in any of the following three sequences:
• Train Operator - For service application of brakes, the operator may choose dynamic or blended (air plus dynamic) braking, which is automatically controlled by the computer in the power car. In emergency braking, the operator has (in addition to the EB position on the brake controller) an electronic emergency brake button, activating all brakes, plus a backup manual air release valve for the pneumatic brake system. Whenever an emergency braking sequence is started, magnetic track braking is also applied.
• Train Crew (or Passenger) - The train has three emergency brake valves available to crew or passengers in each trailing car. The emergency switch is connected to a brake valve which is connected directly to the brake pipe (BP) system. When this switch is activated, brake pipe pressure is released and emergency braking is invoked. Supply of additional brake pressure is also cut off though a valve such that compressed air intake is removed to the pressure reservoirs. During this sequence, train propulsion is disabled.
• Vigilance Control System, Cab System, and/or Central Computer - The Vigilance Control monitors the operator’s activities through his operation of the safety pedal. If its position is not changed within 50 seconds, an alarm sounds. If not acknowledged by position change within five seconds, a penalty brake application is initiated. In Sweden, the automatic train control (ATC) will stop the train if the operator exceeds the allowable speed (plus 10 km/h tolerance), if the operator fails to activate the alerter once per minute, or if grade crossing gates are not down or a vehicle is detected on the track. In U.S. demonstrations, cab signalling penalty results in a full service brake application.
It is important to highlight the significant differences between European and North American operations. In Europe, the X2000 train service braking functions are normally operated using the Automatic Train Protection (ATP) system on board the train, which communicates with train monitoring computers outside the train, locally and with central coordination and dispatching. Swedish National Railroads invested substantial capital on several of its corridors to enable ATP control.
However, the present manual block control system prevalent in the U.S. will not permit ATP operations without substantial redesign and upgrading in the future. Hence, the X2000 is envisioned to function on the NEC, and in other Amtrak corridors, by manual (operator) initiation with computer control assist during a full service or emergency braking regime.
3-21 3.2.3 Braking System Performance
Technical Specifications
Prior to the start-up of the X2000 demonstration runs in the U.S., ABB technicians modified the train to ensure compatibility with overhead catenary voltages and Amtrak standards for brake pipe working pressures. Specification pressures are given in Table 3-4 below.
Table 3-4. X2000 Automatic Brake System Pressures for Amtrak Demonstrations
Brake Cylinder Pressure (max.) Brake Pipe Function Pressure Power Car Trailer Cars Cab Control Car Working Pressure (max.) 1000 kPa (145 psig) 300 kPa (43 psig) 320 kPa (46 psig) Released 760 kPa (110 psig) Full Service/Penalty 600 kPa (87 psig) Emergency Atm. (0 gage)
The demonstration trainset had its brake pressure system adjusted from 75-80 psig to Amtrak Standard S603 main reservoir pressure of 110 psig to compensate for differences between UIC and Amtrak required stopping distances. This adjustment was necessary to accommodate required stopping distances in conventional operations. The calculated differences in stopping distance for a full service brake application are shown in Figure 3-5.
Specified stopping distances for the X2000 trainset are listed in Reference 11 and follow in Table 3-5:
Table 3-5. Specified X2000 Train Stopping Distances from Different Speeds
Braking Mode 200 km/h (124 mph) 160 km/h (100 mph) 130 km/h (80 mph) Specification 1.75 km (5742 ft) 1.05 km (3440 ft) 0.70 km (2300 ft) Full Service 1.45 km (4757 ft) 0.95 km (3117 ft) 0.60 km (1969 ft) Emergency 1.10 km (3609 ft) 0.65 km (2133 ft) 0.50 km (1640 ft)
Full service braking tests were performed on an NEC track north of Baltimore during the U.S. demonstration project. Results of full service braking are shown in Table 3-6 with dynamic brakes isolated, brakes on one axle of a trailer car disabled (to simulate a full passenger load), and on a descending grade of 0.11 percent.
3-22 Full Service
Figure 3-5. Calculated Stopping Distance vs. Speed for X2000 Trainset
3-23 Table 3-6. Measured X2000 Train Stopping Distances, Full Service Braking, U.S. Demonstration Tests
Train Initial Speed Stopping Distance (km/h) (mph) (km) (ft) 48 30 0.11 357 80 50 0.27 899 113 70 0.50 1641 145 90 0.83 2712 0.81 2644 177 110 1.25 4116 1.17 3825 201 125 1.69 5549 217 135 1.90 6250 243 151 3.44 11300
From test results supplied by ABB for the X2000 Demonstration train, the anti-skid system was tested on rail where a soap solution of 2 percent and 3 percent was sprayed on the rails in front of each train wheel to determine stopping distance at 72 MPH. The train in these tests consisted of one power car and a cab control car. The adhesion limit in these tests was 6 percent and 8 percent, respectively.
Stopping distances for these tests were:
Dry 0.47 to 0.50 km (1556-1627 ft)
2% Soap Solution 0.56 to 0.59 km (1831-1936 ft)
3% Soap Solution 0.59 to 0.73 km (1932-2410 ft)
Soap was used to simulate the affects of poor adhesion introduced by the environment between the wheel and rail. According to ABB, the anti-skid system did not allow any slippage to occur during the tests. However, stopping distances were adversely affected requiring up to 27 percent of additional stopping distance with slippery rail in a full service stopping application.
3-24 Diagnostics and Monitoring
System Status Reports. The X2000 driver’s cab is equipped with an operator’s console which continuously monitors safety-critical activities of the operator. Termed by ABB as “Vigilance Control,” this is a logic system designed to extend the “dead man’s brake” concept to constantly monitor movements in the safety pedal which controls train operation.
As the operator depresses the safety pedal to the intermediate position, the “Pedal Intermediate Timer” is actuated and an “Acknowledge” light flashes on the console after 50 seconds of operation. After 5 more seconds, an alarm is triggered for the operator to release the safety pedal within 5 seconds. If he/she fails to do so, the central computer initiates penalty (full service) braking. When the brake pedal is released, the timer is re-set to zero for the next sequence.
Alternatively, the same sequence of events takes place when the “Pedal Intermediate” position is defeated by the operator. For this sequence, there is the inverse signal indicator which lights on the console, “Pedal Not Intermediate.” When this occurs, the timed “Acknowledge” light goes on after three seconds and the alarm sounds four seconds later if no action is taken. Similarly, the operator must move the safety pedal within six seconds thereafter or penalty brakes are applied.
These sequences repeat whenever the train is in motion except when full service braking has already been initiated. While obviously developed to keep the operator alert, the system has several deficiencies which may not be acceptable:
• The Vigilance Control System can be turned off by closing the ECEV valve located in the cab and trailing car. A negligent or careless operator, crewman, or maintenance worker could defeat this system and render its benefits useless. Access to this capability should be severely restricted for U.S. operations.
• Additional fatigue could be induced on the operator by forcing him to depress the safety pedal approximately twice a minute throughout the run. The Brotherhood of Railway Locomotive Engineers (BRLE) could resist this design feature. However, the benefits of this capability appear to outweigh its deficiencies.
Enroute Indications of Failure. In addition to the above description of the Vigilance Control System, the operator’s console employs a rather comprehensive set of fault indicators. The fault indication system gives the operator a variety of visual indications that a fault is occurring through the micro-processor, localized, and central computer diagnostics.
The following functions are monitored continuously:
1) Isolating valve is not energized in regular operation or is energized if the driver’s cab is inactive; or it is either closed when energized or open when de energized
3-25 2) Serious faults in the HSM computer are shown by an “HSM Fault” and “HSM Warning” for minor faults
3) Faulty signal in brake controller
4) ECEV valve fails to release when emergency brakes are applied electrically
5) EP control system valve solenoids are activated too long, too short, or simultaneously
6) Feeding maintained for too long
7) Low BP pressure light when the brake controller is in the “Running” position and brake pressure switch releases concurrent with pipe pressures falling below 64 psi
8) BP pressure switch fails to close in emergency braking
9) Incorrect position of any of the BC pressure switches in accordance with the brake controller lever
10) Communication is lost between the cab controller and air compressor computer
11) Brake pipe maintaining function is isolated by driver’s panel switch
12) Brake pipe pressure transducer signal output is not being received
13) Auxiliary brakes in use
14) ECEV valve has been manually closed
15) Anti-skid valve is activated longer than eight seconds
16) Pressure switches indicating low BP pressure and emergency brake application conflict
17) Magnetic track brake is not functioning during emergency brake application or is active when emergency braking is not used; or, magnetic brake is not active during emergency braking and vice-versa
18) Fault signals originating from the U/I convertor associated with the bleeding valve
There are two modes of display in the operator console: 1) normal indication, and 2) auxiliary indication when the train is operated in this mode.
3-26 A set of software protocols are built into the fault monitoring system to alert the operator of the current status of each safety-critical brake and speed function:
The emergency brake (EP) from the vigilance control system, Constant monitoring of the brake pressure (BP) switch when train speed is five km/hour or greater, Status of the “Activate Emergency Brake Valve” indicator and its sister “Feeding Emergency Valve” indicator light in the locomotive cab, Indicator light and active train control of the emergency brake originating either from the power or trailing cars.
Inspection and Test Requirements
The standard automatic air brake system leak test (tightness test) may be done using a special switch in the driver cab, providing that the cab is active. This switch deenergizes the isolating valve, cutting off the brake pipe pressure from the main reservoir supply. Brake pipe pressure drop can then be monitored in the time-honored way.
Braking System Effects on Vehicle, Guideway, and Infrastructure
Thermal Effects. During pneumatic braking stop distance tests on the NEC, the temperature of the disc brakes was monitored. Temperatures were measured by using a thermocouple at the end of each stopping test. According to ABB furnished data, disk pad temperatures were not allowed to exceed 752 degrees Fahrenheit and disc temperatures were cooled to at least 250 degrees Fahrenheit before proceeding with the next test. These temperature ranges were supplied by Knorr/NYAB to prevent thermal damage to the wheels or pads.
Test results show a maximum recorded temperature of 277 degrees Fahrenheit. If these results were accurate, there is sufficient thermal margin at running speeds up to 135 MPH in a full service braking application. Thermal crack initiation has been shown by a number of researchers to become pronounced when high surface temperatures are sustained over a long period of time (critical wheel temperature damage to the microstructure can occur in the 900- 1100 degrees Fahrenheit range). Since wheel tread braking amounts to a relatively small portion of the total braking power, wheel heating is not anticipated to be a problem. Substantial research and development effort has gone into the design of disc brakes for European high speed trains (Ref. 10, for example). As a result, the disc brake system is well suited for high energy dissipation and high temperature events.
Mechanical Effects. ABB has provided data which indicate brake pad useful life to be approximately 120,000 km (74,400 miles) in service. The complementary expected life for brake discs is 10 times pad life, or 1,200,000 km (744,000 miles).
ABB further states that all discs are replaced at the time of major overhaul together with the wheels themselves. Apparently, wheels and discs are not turned as a regular maintenance activity to prolong their useful economic life. No data were provided on the useful life of magnetic track brakes or their associated lining life.
3-27 To the extent that the ratio of dynamic/regenerative to friction braking is increased in blended braking sequences, mechanical wear is proportionately reduced on disc brakes and magnetic track liners. This is one of the primary advantages of regenerative braking. Magnetic track brakes are proportionately most effective in the lowest end of the speed profile, but generate high frictional forces and can possibly subject the rail to damage by wear and heating as speeds increase.
The magnetic track brakes are said not to affect track circuits because dc fields are used.
3-28 D C A 2 A 2 A 3 S A 3 Y N N N N Y FS N N N Y N FT N S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Assum e driver can isolate system and continueline atspeed reducedfa iludepending re . speed oron degree of Controller sends a signal to both s ig n a ls . Operator has indications fromwithin speedoperating lim its with defined failedBraking for brakes. effort is too high resultingTrain doesM ustnot increaseslowrequested, quickly level possibly ofenough. braking even emergencyTrain does not slow down. Must W heelslide indicated to driver. How Detected/Response computerscomputer at all times informis alwaysso ation, the receivingsecond now it sendsthe the control isolate failed brakes and continue in rapid levelspeed ofdecrease. braking Reducerequested. b r a k in g . utilize emergency brake. monitoring. Possibly manually stopping distance. Over application of brakes on one Braking effort is too low, increasing Braking does not occur at all. track causingtra c k . wheel slide for the N o effect. computerThere is at aeach central end of the trainset. The car withexperience failed wheelcomputer slide. m ay Rapid decreaselevel indesired speed beyond Effect on Overall Braking System Table 3-7. X2000Table3-7. F M E AWorksheet Braking does not occur at ail. Braking desiredapplied braking towheel truck slip.level iswear above resultingon This wheels causes in and excessive rails. Braking is under desired level for Results inlevel, m aintaining not alleviating current wheelbrake slip. N o wheelcar. slideW heel protection slide possible rfor a ils . the resulting Braking foroccurs the trainset.above desired level the trainset. N o effect.computer There is at aeach central end of the in excessive wear on wheels and Effect on Braking Subsystem tra in se t. Fails with output failing to No signal for b r a k in g re q u e ste d . Signal for too modulate thebrake cylinderp re s su re . braking when F a il s o ff. Signal formuch too braking little braking. F a il s o ff. Failure Mode AntiSkid System (2 car and cabcar), control H SM Computer Brake (controlled one in each of power U n it. AntiSkid system for a valves/truck,for tread 1 each andbrakes disc for trucks; the motor for 1 valve/truck the trailer tracks) Driver’s ConsistsBrake Valve. Controllerof Brake (In power by central computers and- cab controland Electropneumatic cars), computer controls thec a r) X2000 TiltingC oTrain m p o n e n(Sweden) t Page 1 of 8 Slave Computereach trailer (1 forcar. This' Central ComputerPower Car incomputer (This controlsAntiSkid the the system power for analogcar and valve)the
3-29 B 3 S D D A 2 C FS N Y Y N Y Y FT Y Y N N S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; Y= Safe; Fail = FS Tolerant; Fault =FT How Detected/ResponseAssum e ofoperator lower receives braking indication effort than requested. reduced M ay speed dependinghave orto lineoperate on speeddegree at of failure. Operator has indications of failure to accept load.braking Valve onimmediately powerfor friction car and is automaticallyapplied Computer to reacts to lower fulfill the brake demand. regenerative brakingv a lvby e . allowing AntiSkidcomputer. system monitoredFailure of by motor, driver and continuesp e e d . at lower speed or line Speed reduction. Com puter eventuallyrecovered stops if via pressure m ain notreservoir. more friction braking via the analog m ust stop and isolate the wheelset m onitoringpressure. notifies Trainoperator slows of low and Effect on Overall Braking System effort of one truck. Reduces available braking by the Regenerative braking is unavailable. supplement for lost regenerativeUnintentional wheel slide for the Immediateapplication and automatic of friction brakesb rato k in g . Friction brakes applied for all cars. fulfill brake demand, i.e., attempts to alleviate wheel slide. motor track axle. AntiSkid system Table 3-7. X2000Table3-7. F M E AWorksheet (cont.) Effect on BrakingBraking Subsystem applied to truck is below desired brakingreduced orlevelassociated no resultingbraking with infor the thefailed truck control. Unintentional wheel slide for the Regenerative braking is unavailable. Loss of or decrease in regenerative attempts to alleviate wheel slide. motor track axle. AntiSkid system Friction brakes applied for all cars. braking for the m otor track. Fails with output Failure Mode requesting cylinderbrake pressure Load rejected, or to be vented,thus keeping the Bearing failure, Does not produce valve open. axle seizes. power failure current to toreturn pantograph. Fails with Low P r e s s u re Regenerative Braking System C o m p o n e n t AntiSkid System (2 PantographCatenaiy or power (Assume two per Motor Car Trucks X2000 Tilting Train (Sweden) v a lv e s A r u c k , 1 e a c h tmcks; 1 valve/ttuck Page 2 of 8 Pneumatic Friction Brakes acceptance of load Traction Motor tru c k .) for tread andbrakes disc for the motorfor the trailer tm cks) Motor Car TrucksA ir Brake Pipe (ABP)
3-30 A 3 C B 3 B 3 S C Page 3 of 8 Y N N Y N FS N N Y N Y FT S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; =Y Safe; Fail = FS Tolerant; Fault =FT slightly reducedOperator speed if notified required. via computer at a reduced speed.Operator notified viaslightly computer reduced speed if required. Operator notified viacar’s computer friction brakes, i.e. controlexcessive wear and overheating is Operator notified viastop, computer only failsafe, or the operatorfriction brakescontinuing (controltolerant at avalve) reducedonly. and speed, Operator fault notified viabraking computer forbraking, the car realisticallyif via available, regenerative continueor, more operation at a braking forisolating the truck i.e.the the perhapscar’s control frictionby valve, brakes, and continuingm onitoring. Continue operation at a monitoring. Operatorvalve, can and isolatelim continue its required. within speed Ifp ro bnot, a b le . then How Detected/Response monitoring. Eithermust the decreasetrainperhaps w illlevel by ofisolating braking the car’s monitoring. M ust increase level of monitoring. M ust decrease level of stopping distance. stopping distance. One actuator/disc, brake effortwear is on brakesoverheating and/or of possible brakes. Braking effort is too low, increasing Unintentional friction braking for Braking effort is too low or constantlyeffort applied from equivalent one disc. to Excessive the track vassociated a lv e . with the failed unavailable for the track, increasing Effect on OverallThe Brakingoperatorthus canelim Systemisolatethe inating car, this iffriction brakingvalve, braking is not for requested. Table 3-7. X20003-7. TableF M E AWorksheet (cont) Braking is under desired level for One actuator/disc,constantly brakeeffort applied effort from equivalent wearis one on disc. brakes overheatingto Excessive and/or ofpossible brakes. Braking above desired level for the the track traor c kunavailable . for the Braking is under desired level for track. Mthe ay AntiSkid result in System.overworking th e c a r. Effect on Braking Subsystem This w illthe resultbrake infrictionpipe slow and lybrakes.applying venting the Fail disc brakes allow ing pressure s u p p ly in g o n to the brakes. b ra k e s. Signal forlittle too braking, fails closed not Signal formuch too braking, fails open pressure to Signal forlittle too braking, fails closed. Signal formuch too braking, f a ils o p e n Failure Mode 1/truck) W ill effect Disc, and Calipers disc and treadof associated brakes track. D isc Brake Actuator,associated andwith actuator discdiscs/axle) (2 Relay Valve (2/car, or X2000 TiltingC oTrain m p o n e n(Sweden) t associated car. Control ValveW ill effecttread (1/car) disc brakes and of the
3-31 S B 3 A 3 B 3 D C D FS N N N Y Y Y FT Y N Y Y N Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; Y= Safe; Fail = FS Tolerant; Fault =FT How Detected/Response Com puter m onitoring indicates low er brakingAssum effort e reducedoperator than speed. requested.can continue at Operator notified viacar’s computer friction brakes, i.e. control excessive wear and overheating is Com puterlow m onitoring er brakingAssum indicates effort e reducedoperator than requested.speed.can continue Com puter at operator m onitoring of compressor notifies running and m onitoring. Operatorvalve, canand limisolate continue its required. w ithin pspeed If ro b anot, b le . then Com pressor (s) can be shut off to reservoir pressure. r e s e Assum r v o ir . e safetyCom puteroperator m onitoring of com notifies pressor condition, Assum e reliefoperator valve is notified operates andautomatically. pressure relief valve is available on prevent further pressure build up. not running, and reservoir pressure. Worksheet (cont.) FMEA Effect on Overall Braking System One actuator/disc,applied, brakelost brakingeffort not capability One actuator/wheel, brake effort is equivalent to effort from one disc. constantly effortapplied from equivalent one wheel’s to tread One actuator/wheel, brake effort not and/or possibleb ra k e s. overheating of applied, lostequivalent brakingwheel’s to capabilityeffort tread from brake. one reservoir and continues beyond Friction brakes cannot be released braking. Excessive wear on brakes available on m ain reservoir. Pressure builds in the m ain once applied. Assum e pressure relief valve is norm al levels. Table 3-7. X2000Table3-7. Effect on Braking Subsystem One actuator/wheel, brake effort is One actuator/disc,applied, brakelost braking effort not capability constantlyeffort applied from equivalent one wheel’s to tread equivalent to effort from one disc. and/or possibleb ra k e s. overheating of One actuator/wheel, brake effort not braking. Excessive wear on brakes applied, lostequivalent braking to capabilityeffort from one disc. M ay notsystem. be able to The energize result brakeis that the reservoir and continues beyond H igh pressurer e s e r v o builds ir . in main Pressure builds in the m ain friction brakesm ay be cannot unavailable. be released or noim al levels. Failure Mode Fail disco brakes f f Fail treado n brakes Fail tread brakes Fails on, switchpressure fails to F a il s o f f o f f turn compressoro f f Fails highp re s su re X2000 TiltingC oTrain m p o n e n(Sweden) t D isc BrakeDisc, Actuator, and Calipers Page 4 of 8 associated andwith actuator discdiscs/axle) (2 M ostly for wheel Com pressor, one/train. Tread Braketread Actuator,shoes (1/wheel)conditioning. one/train, 500 liters M ain Reservoir,
3-32 B 3 A 3 B 3 C A 3 C S Page 5 of 8 N N Y N Y N FS N Y N Y N N FT S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Operator notified viaslightly computer reduced speed if required. Maintenance and inspection checks. Assum e operatorof pressure is notifiedlevel in r ein sM e rvcab RP. o ir. Try to Computer m onitoring indicates low Operator notified via computer m onitoring. Continue operation at a How Detected/ResponseComputer m onitoringoperation. indicates Assum low e operator can maintain pressure via the m ain refill via M R P and m ain reservoir. monitoring.braking M ustforisolating decreasethe car i.e. theperhapslevel thecar’s controlof byatfriction a reducedvalve, brakes, andspeed. continuing pressure of reservoirbegin and comcompressor pressor operation. pressure of reservoir. Attempt to Worksheet (cont.) FMEA Unintentional friction braking for Braking effort is stoppingtoo low distance.of ' contaminationcorrosion and possible over time. unavailable for the car, increasing Effect on OverallFriction Braking brakesexcessive inoperableSystem running orof compressors or W ear on components. System Potentiallybrakes unable for braketo entireapply supply trainset havefriction reservoirs enoughbecause to apply pressure m aythe not frictionon Pressure their brakes.own notfriction available brakesfailed to for reservoir.apply the track with the the car associatedv a lv e . with the failed both w ill result. Table 3-7. X20003-7. Table Braking car.above Mdesired ay result level in for overworking the the Braking is under desired level for corrosion of components over time. that once applied,the friction they brakes w ill notare be able to be Antiskid System. released or reapplied. W ear on components. Possible Pressure is not available to M R P so Effect on BrakingM ay Subsystemnot system.be able to The energize result brakeis that the hard tryingp re s suto re reach . the desired the car or unavailable for the car. Pressure frictionnot available brakesfailed to forreservoir.apply the track with the friction brakes cannotmay be try released to compensate or by running may be unavailable. Com pressor s u p p ly in g w e t Fails with low Fails with low Signal formuch too braking,fails open Signal for too allow ing pressure Fails with air too p re s su re pressure tob ra k e s. little braking,fails closed not to the brakes. F a il s lo w p re s s u re p re s su re Failure Mode /relay valve or 2/car, 1 (MRP) Brake Supply M ain Reservoir Pipe each 50 liters. Relay ValveW ill effect (1/car)of discassociated brakes car. A ir Dryer/Filter Reservoir, 1/truck, i.e. Trailer Car Truck X2000 TiltingC o mTrain p o n e n(Sweden) t M ain Reservoir,one/train, 500 liters
3-33 B 3 S B 3 B 3 B 3 B 3 B 2 N FS N N N N N Y FT Y 1 Y Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Computer m onitoring indicates low How Detected/Response refill via M R P and m ain reservoir. Computerindicate m onitoring batteryreliance should status. on other M ore brake systems if pressure of reservoir. Attempt to m any of these failuresCom puter occur.of m onitoringpressurization indicates of m lack agnetic track deployed so the effect is Assumslightly e only detection is decreased disc brakes, result of b ra k e s. Assum e only detection is decreasedincreased stopping distance. deployed so the effect is slightly Signal in cab?? inspection/diagnostic.Unusual wear to . braking. Other systems should be braking. Other systemsincreased should stopping be distance. Worksheet (cont.) FMEA Effect on Overall Braking System Pressure notfriction available brakes to forapply the car with the Decrease or loss of m agnetic track failed reservoir. Since thissystem, is an other shouldemergency braking be fullybraking systems deployed to stop should be fully deployedEffect to stop depends on extent of ATO senses train not slow ing down, braking for the truck. train immediately. system, other brakingtrain systems immediately. shoe m ay be negligible, while loss increases electrodynambraking effort ic andin disc brakes. Since this is an emergency braking problem. Loss ofof mcontact ultiple at shoesone may require further emergency action. Table 3-7. X20003-7. Table Effect on BrakingPressure Subsystem not available to apply friction brakesfailed forreservoir. the car with the Decrease or loss of m agnetic track Decreased magnetic braking force Loss of magnetic track braking for braking for the truck. th a t u n it. Loss of magnetic track braking for for that unit Loss of Eddy Current braking. th a t u n it. Fails with low decreased power Fail to make Loss of power ora v a ila b le Fail to engage Failure Mode p re s s u re contact with rail brake shoestra cwith k Fails to cunent/producecany F a il O f f m agnetic field Brake Shoes (2 (Assum e systemone battery per track) C o m p o n e n t Brake Supply stationary, 10 floating) Actuators (Air Batteries (24v) X2000 Tilting Train (Sweden) Reservoir,lite rs. 1/car, 50 Page 6 of 8 Coils, switching Brake Coil/W iring C y lin d e r s ) Magnetic TrackTrailer Brakes Car Trucks Eddy CurrentSystem Brake (Magnetic equip., etc.) Eddy Crttfehf Braking System *
3-34 S D D D D D B 2 B 2 V FS Y Y Y Y N N FT Y Y Y Y Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Com putersignal indicates error,spite the but electronicof braking the failure. occurs in How Detected/Response switches to operate the dynam ic and Com puteremergency indicates failure,braking but is still available.Com puteremergency indicates failure,brakingCom but is puter stillemergency indicates available. thebraking failure, is but still Com initiated. puteremergency indicates thebraking failure, is but still Brakes initiated. w ill not be applied Braking w ill not occur without emergency brake valve. immediately,individual indicatingbe thatactivated. to another the valve must further action.independent The ofdriver the brake has,magnetic valve, brakes or the cab Worksheet (cont.) FMEA Effect on Overall Braking EmSystem ergency braking is still initiated. No effect. This is a backup system No effect. This is aEm backup ergency system braking is still initiatedEm ergency braking is still initiated applied as a result of this action. to the Driver’s Brake Controller. to the Driver’s Brake Controller.via the direct venting of the brake One of theemergency two remainingbe valves initiated. in the car must N o emergency brakes w ill be p ip e . via the computer signal. Table 3-7. X2000Table3-7. Brake pipesim ultaneously.is direcdy vented One of theemergency two remaining valves in the car must If the E Coperator E V is isemergency manuallysignalled.a p brakes closed, p lie d If . witthe ill fails, not thebe No effect.to the Driver’s This is aBrake backup Controller. system No effect.to the Driver’s This is aBrake backup Controller. system Em ergencysim braking ultaneouslyelectronically is alsorequested via the computer. Effect on Braking Subsystem Direct ventingoccurs ofwhenemergency the thebrake controller pipeposition is andin thethe pressure be initiated. maintenancepipe function is disabled. for the brake 1) Driver’s brake Fails to directly Fails to directly signalled via the Fails to cabsignal emergency Fails to directly Signal notcomputer sent to to Direct venting ofdoes not occur. v a lv e , 2 ) V ig il a n c econtrol, oremergency 3) brake vent the brakep ip e . vent the brake valve to brakevent thepipe. vent brake pipe. initiate failure. the brake pipe Electronicdoes signal not initiate valve in cab. p ip e w h e n Failure Mode b r a k in g . ElectricallyEmergency Controlled(ECEV) Valve Emergency(3/trailer Valves car) Manual A ir Release Emergency(2Arailer Valve car) Crew/Passenger V a lv e Conductor’s Driver’s Brake Valve Electric EmBrake ergency Button X2000 TiltingC oTrain m p o n e n(Sweden) t Page 7 of 8
3-35 S D Y FS FT Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT w ill be stopped. How Detected/RespOnse Brakes w ill be applied, and the train Worksheet (cont.) FMEA specified time. Effect on OverallBrakes Braking are applied System by the system if no response is received within a Table 3-7. X2000Table3-7. specified time. Effect on BrakingBrakes Subsystem areno applied response by is the received system withinif specified time to safety systemspeed or lim it is Operator failsrespond to within a signal from this e x c e e d e d . Failure Mode X2000 TiltingC oTrain m p o n e n(Sweden) t Page 8 of 8 Vigilance Control 1. Other systems can supply extra braking. extra supply can systems Other 1. 2. Eddy current brakes not available in revenue service. Trucks would be equipped with either eddy current brakes or magnetic track brakes, not both. not brakes, track magnetic or brakes current eddy either with equipped be would Trucks service. revenue in available not brakes current Eddy 2.
3-36 3.3 INTERCITY EXPRESS (ICE)
3.3.1 General Description of Trainset
The German InterCity Express (ICE) has been in joint development for over a decade by both the railway industry and the German Federal Railways (Deutehes Bundesbahnen). In this development program, two basic objectives were met: test operations at speeds up to 345 km/h (214 mph), and revenue operations at speeds up to 300 km/h (186 mph). These objectives were met by analytical studies (computer simulations of train stability at high speeds, for example), laboratory roller rig experiments, and extensive high-speed running on specially-prepared test tracks. A maximum speed of 407 km/h (252 mph) was actually achieved in tests.
The ICE train is now in service at track speed limits of up to 280 km/h between Hanover and Wurzburg allowing start-to-stop schedules between certain cities of 180 km/h or higher. This has been made possible by construction of new high-speed lines (Neubaustrecke, NBS) and upgraded automatic train control equipment on some existing lines. The ICE train consists of two power cars and up to 12 (14 maximum) trailer cars in the standard two-bogie, four-axle configuration for all cars. Weights are as follows:
• Power car - 78 metric tons (86 tons)
• Trailer car - 52 metric tons (57.3 tons)
• Service car - 52.6 metric tons (58 tons)
• Restaurant car - 55.5 metric tons (61.2 tons)
The total train weight is 784 metric tons, 864 tons (two power, one service, one restaurant, and 10 trailer cars) at a length of 357 meters (1171 ft). Current service speed is listed at 250 km/h (155 mph) with a maximum speed limit of 280 km/h (174 mph).
A modified ICE train was tested and demonstrated on Amtrak’s NEC trackage during the summer of 1993, reaching speeds of 261 km/h (162 mph) during these tests. Revenue service demonstrations were run as a Washington to New York Metroliner train. The ICE train is expected to be offered by the consortium of Siemens Transportation Systems, Electro-Motive Division (GM) and AEG Transportation Systems as one group in Amtrak’s upcoming high speed train procurement.
3.3.2 Braking System Design
The braking system of the ICE train has been described in several publications [Ref. 12,13,14] and reports [Ref. 15]. Details of the braking system on the ICE train for NEC demonstration was provided by Knorr-Bremse AG through Siemens Transportation Systems, Inc. [Ref. 16]. The salient features of the brake system include:
• Dynamic/regenerative braking, returning kinetic energy to the power grid,
3-37 • Computer-controlled priority allocation of braking between dynamic and friction brakes,
• Computer-assisted fault monitoring, diagnostics, and automatic brake test,
• Communications via a fiber optic waveguide train data bus.
Major components of the ICE brake system are described below.
Major Braking Components
The ICE trainset brake control is based on the pneumatic brake pipe complying with UIC standards. Basically, the system uses (in order of preference) three types of braking: 1) regenerative braking, 2) pneumatic/electro-pneumatic friction braking, and 3) magnetic track brakes for emergency braking. There is the option of using eddy-current track brakes instead for both emergency and service braking. These are used in Germany on the ICE-V trainset, but were not included on the demonstration ICE trainset.
Dynamic/Regenerative Brakes. Electrodynamic (regenerative) braking is available on the axles of the power cars, using the ac traction motors as generators to return power to the catenary. Up to 3,300 kilowatts of power can be generated per power car. If the catenary (power system) rejects the load, however, dynamic braking capacity is lost. Microprocessor control of braking uses the dynamic braking preferentially to maximize energy regeneration and gain efficiency in operations.
Air Activated Disc Brakes. All cars (power and trailing) are equipped with a conventional automatic electro-pneumatic brake system. This pneumatic system is designed to provide alone, sufficient braking power to meet both service and emergency braking requirements in case other elements of the brake system fail. Physically, the system includes:
• Two non-ventilated discs (cast steel alloy, sintered metal pads) on each power car axle, with force generated by a double caliper brake cylinder unit for the two discs.
• Four ventilated discs (cast iron with organic composition pads) on each trailer car axle, with force generated by a single caliper and brake cylinder per disc.
Substantial research and development effort has been invested in these high-temperature brake discs to assure reliability under high thermal and mechanical stresses. In addition to the high temperature stability, these disc brakes offer less sensitivity to moisture and more uniform friction coefficients at high speeds.
Magnetic Track Brakes. Electro-magnetic track brakes are used on the trailer car bogies for emergency braking situations. This type of brake has been used by Deutches Bundesbahnen (DB) for more than 20 years, but because of substantial wear it is used only in emergency braking.
3-38 Parking Brakes. The parking brake on the coaches consists of a hand brake that actuates a separate caliper on one disc of one axle per car. The parking brakes on the power car function through spring-loading of disc pads by the brake cylinders. These are released by air pressure.
Braking Control Components
The brake system of the ICE trainset consists of a number of subsystems and components optimized to provide reliable control, plus status and diagnostic information. These major subsystems are described below.
Air Supply. Compressed air for the automatic air brake system is supplied by a Type SL20- 5 rotary screw compressor in each power car, each of which provides about 2170 litre/minute (76.6 cfm) at a pressure of 10 bar (145 psig) at a rotational speed of 3400 rpm. Each compressor is driven by a three-phase ac motor at about a 22.5 kW power level. One compressor can supply the requirements of the whole train. The compressor has an integrated cooler, and air then passes through a dual chamber air dryer with integrated oil separator. A heating cartridge is mounted on the drain valve to avoid condensate freezing in winter.
The main air reservoir pressure switch is set (for U.S. operation) to cycle between 8.5 bar (123 psig) and 10 bar (145 psig); and the safety valve is set at 10.5 bar (152 psig).
HSM Driver’s Brake Control Valve. The driver’s brake control valve Type HSM-PEP, located in the power unit cab, controls the automatic air brake system (with additional electro pneumatic EP-assist units) by indirect (or direct) regulation of the brake pipe pressure. The valve is used to set the desired train braking level, either manually by the operator or by the automatic train control (ATC) system. Manual operation has priority over the ATC operation. Set values are monitored by microprocessor brake control units in power and trailer cars, which control the dynamic and/or friction brake systems. In addition to the electronic control, the driver’s brake valve contains an independent pneumatic control. Changeover can be effected manually by the operator or automatically through fault diagnosis by the computer. The major components of the driver’s brake control system are:
• Driver’s brake valve FS1 ♦ Electrical assimilation button (for releasing overcharged brakes) ♦ Electronic/pneumatic operation switch (switches off microprocessor) ♦ Emergency vent valve NB4 (direct venting of brake pipe) ♦ Emergency brake unit ♦ Changeover unit (electronic to pneumatic operation) • Relay valve unit • Equalization reservoir • Assimilator function reservoir • Electrical relay for emergency cut-off solenoid valve * Electronic microprocessor control HSM
The driver’s brake valve FS1 has two (redundant) potentiometers generating the brake force electrical analog signal. In addition, there is a pressure regulator setting the equalization
3-39 reservoir pressure, a rapid vent valve for direct or pre-controlled venting of the brake pipe, a key-operated cut-off valve, and cam-controlled switches for a) suppressing passenger emergency brake commands (inactive in U.S. demonstrations), b) emergency brake applications, and c) traction. The valve has notched positions for the following:
♦ Filling (suppression of passenger emergency command — not active for U.S. operations) ♦ Running position • Service brake (and release) position - Minimum application [1] - Service brake [2-5] - Suppression [6] - Service brake [7] - Full service [8] • Emergency
Driver’s Brake Control Unit (Brake Electronics). The brake electronics unit, located in a 19-inch rack installed in the power car, connects with the control desk, the fiber optic train data bus, the central vehicle diagnostic computer (“DAVID”), and with the drive control/regenerative brake through the train control unit (ZSG), as shown in Figure 3-6. The unit also communicates through a second RS 323 bus with microprocessor-based anti-skid units (MGS), sharing speed and diagnostic information.
The driver’s brake control unit (HSM-MGS) combines brake control electronics, comprehensive diagnostics of the automatic air brake system, and anti-skid (wheel slip) protection for the power car, both in braking and traction modes. The unit controls brake pipe pressure (through EP assist) to set or release brakes, distributes brake forces to available brakes, controls the automatic brake test and continuity check, generates diagnostic data for the power car, and initiates emergency braking electrically. Each power car has one HSM- MGS unit which exchanges data with the second power car, the coaches, and other electronic devices on board via a serial interface. Data distribution is organized by the train control unit (ZSG).
Brake Control/Anti-Skid Device. The brake control and anti-skid device (MGS-SVB) is located in the center trailer car in a single 19-inch rack. This unit controls the trailer car anti skid functions, processes signals commanding the electro-pneumatic (EP) solenoid valves for the main reservoir pipe pressure control, processes brake diagnostic information, and controls the magnetic track brakes. As shown in Figure 3-7, the unit communicates with the diagnostic computer (“ZEUS”) and with the fiber optic train data bus through an RS 485 bus. Brake control signals are passed directly to the unit, bypassing the ZEUS computer, to assure fast response.
The SVB portion of the device detects the condition of each brake on the cars (pneumatic and hand brakes), monitors the operational ability of brakes, and processes this information to generate detailed status and fault messages. These data and reports are transmitted via the train data bus during both tests and in service. In addition, the unit monitors (and blocks, in the event of failure) commands to the EPZ solenoid valves.
3-40 Figure 3-6. Brake Control Schematic for IC E Power Car (Ref. 12)
3-41 Figure 3-7. Brake Control Schematic for IC E Trailer Car (Ref. 12)
3-42 The MGS portion of the device provides microprocessor control of wheel slip through modulation of brake cylinder pressure. Control logic is based on individual axle acceleration and speed criteria to maintain braking force at optimum levels without loss of adhesion.
Anti-Skid Device (MGS). The anti-skid (wheel slip control) device reads the signal from a speed sensor, which is an 80-tooth ferromagnetic gear wheel on each axle scanned by a stationary magnetic pickup. These pulses are used to determine wheel rotational speed and change in speed, and these data are then processed to detect wheel slip through approximately 30 combined speed and retardation criteria. The microprocessor controls the anti-skid valve, which is in turn connected pneumatically to the distribution valve, allowing brake cylinder pressure to be momentarily reduced to restore the wheelset torque balance. The unit has non volatile memory and an additional microprocessor-independent safety circuit to assure reliability.
The anti-skid device on the power car interfaces with the traction control as well as the dynamic and friction braking systems to assure optimum use of adhesion during both power and braking modes. To improve wheel/rail adhesion in adverse conditions, power cars are also equipped with sanders to sand -the rail ahead of the leading wheelsets of the two bogies of the leading power car. Sand is metered according to train speed, above or below 140 km/h (87 mph), to distribute roughly the same amount of sand per distance traveled.
Passenger Emergency Brake. In revenue service on the DB, there is no emergency brake valve available for passenger access, only crew notification of an emergency. For demonstration in the U.S., however, passenger emergency brake applications could be initiated electrically by opening the emergency loop circuit with pull boxes in the coaches, venting the pre-control pressure holding the vent valve (NB11) with the magnet valve (SBV).
Deadman Control. The ICE power cars are equipped with “deadman” control which interface with one of the two magnets (FGN) which, when deenergized, cause a full service pneumatic brake application. The deadman control, however, can be pneumatically cut out by a cock [Ref. 16].
Brake System Operation
The ICE braking system is designed primarily for computer-controlled automatic speed control operations in which the on-board system is integrated with track circuits controlled from a central dispatching computer. Manual operation can override the automatic train control, but operation is still enhanced by the on-board computers and microprocessors through controlled deceleration, priority distribution of braking, and fault monitoring and diagnostics.
Automatic (Normal) Operation. Train speed is set by the automatic speed control unit (AFB) based on track circuit signals. Distribution of braking forces is executed by the AFB electronics, which will transmit a set value of dynamic braking to the traction control and any set value for additional friction braking to the HSM electronics, which in turn controls the brake pipe pressure.
3-43 Manual Operation. This mode of operation can be selected, and then the distribution of braking forces is executed by the HSM electronics. Manual operation has priority over the AFB unit. Priority braking first uses the regenerative brakes, then brings in trailer car brakes as required by speed level and deceleration needs. The power car disc brakes are not used as long as regenerative brakes are active. The dynamic brakes can be suppressed and only disc friction brakes used if, for example, disc de-icing is necessary.
The traction control receives a set value from the train control. This set value can be reduced by the HSM to achieve an optimum distribution of braking power. Control of the dynamic brakes has hysteresis to prevent unnecessary cycling of set and release.
Pneumatic Operation. In the event of an electronic failure, the brake system can switch to pneumatic operation, either manually by the operator or automatically by computer diagnostics. This mode of operation can be maintained in normal service, but wear increases on brake pads and discs.
Emergency Brake Application. In an emergency situation, all available brake systems (including the magnetic track brakes) are actuated at full levels. In the powered bogies, brake cylinder pressure remains locked except at speeds higher than 160 km/h (100 mph). In this higher speed range, a two-bar (29 psig) pressure is applied to supplement the dynamic braking, which drops off in braking power with higher speeds.
3.3.3 Braking System Performance
Technical Specifications
There is a maximum deceleration rate of 1.4 m/s2 (0.143 g, 3.12 mph/s) with all braking systems operating, but a limit of 1.3 m/s2 (0.133 g, 2.90 mph/s) is imposed. Braking with only friction gives a deceleration rate of 0.9 m/s2 (0.092 g, 2.01 mph/s), where a rate of 0.85 m/s2 is required by the UIC. A rate of 0.7 m/s2 (0.071 g, 1.56 mph/s) is used to compute stopping distances. The dynamic brakes provide alone a deceleration rate of about 0.25 m/s2 below 140 km/h, but drop off to about 0.1 m/s2 by 280 km/h. Calculated braking distances for different combinations of ICE brake systems are shown in Table 3-8.
Diagnostics and Monitoring
The various brake components and subsystems are continuously monitored to determine current status and to warn of failures. The objectives of brake system monitoring and diagnosis are to maintain as many functions as possible with component or subsystem failures, and to define conditions and capabilities of the brakes at the time of failure. Error messages are reported to the appropriate computer by error codes which allocate the fault to specific components or subsystems. Faults are displayed to the operator and stored in nonvolatile memory.
Diagnostics and monitoring functions include the automatic brake test, which is initiated by the central computer (DAVID) as part of the automatic procedure to put the ICE train into service. This is controlled by the HSM of the occupied power car. The HSM of the
3-44 Table 3-8. Calculated Braking Distances for the ICE/USA Demonstration Train (Ref. 16)
Initial Speed, Friction Friction plus Friction plus Friction plus km/h (mph) Brakes Dynamic Brakes EM Track Dynamic plus Brakes EM Track Brakes meters (ft) meters (ft) meters (ft) meters (ft) 145 (90) 1010 (3314) 830 (2723) 790 (2592) 680 (2231) . 177 (110) 1480 (4856) 1245 (4085) 1160 (3806) 1015 (3330) 210 (130) 2020 (6627) 1750 (5741) 1610 (5282) 1440 (4724) 242 (150) 2650 (8694) 2340 (7677) 2140 (7021) 1950 (6398) unoccupied power car and the SYB units of the trailer cars have execution (“slave”) functions only.
The HSM electronic unit initiates braking actions step-by-step in the automatic brake test. Brake test signals are transmitted to the subsystems via the fiber optic train data bus, and each subsystem carries out the commanded special test. A positive acknowledgement of each test criterion must be received within a set time interval, otherwise the inverted status (error) remains active. Each brake subsystem determines the correct function or a fault by self- diagnosis, comparing the set value with the actual value from a sensor. Resulting brake test diagnosis data are transmitted to the vehicle diagnostic system (computers DAVID and ZEUS) and to the HSM electronic unit. Partial brake subsystem failures are stored in the HSM electronics unit and are used in calculating distribution of braking forces.
The diagnostic system is sketched in Figure 3-8.
3.3.4 Braking System Effects on Vehicle, Guideway, and Infrastructure
Electro-magnetic rail brakes exhibit excessive wear when used and are therefore restricted to emergency stops. Similar wear of the rail running surface is probable. An eddy-current braking system is totally non-contact. It will not eliminate the use of either friction or dynamic braking, especially at high speeds. As previously stated, Amtrak is not considering the use of an eddy-current brake. However, if eddy-current braking were under consideration, substantial gains could be realized at all friction braking contact surfaces because the contribution of friction braking would decline significantly. Test results of the ICE on DB were furnished in a report provided to Mr. A1 Shaw, Track Design, Amtrak. The German ICE tests revealed rail heating could be a problem with eddy-current brakes when trains are run frequently over a given track segment. Amtrak train frequency is not likely to approach those headways currently operated on DB. Some electro-magnetic interference (EMI) problems have been noted by DB in tests of eddy current brakes, particularly with axle counters and older-type track circuits.
3-45 - Power Car - - Trailer Car - - Power Car -
DAVID DAVID Text display Text display fibre optic data bus
0 Train-Control ZEU$ Train-Control Interface Text display Interface
0 0 0 HSM MGS-SVB HSM Brake-Electronic Brake-Electronic Brake-Electronic
^ 7 ^ ^ $ Sensors Sensors Sensors ICE. Diagnosis System (DAVID, ZEUS: Diagnosis-Computers)
Figure 3-8. Diagnostic System of IC E Trainset (Ref. 13)
3-46 C B 2 D B 2 S A 2 D P a g e 1 o f 6 N Y Y 4 N Y N FS N Y 1 N Y Y Y FT S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Indicator light arid brake Indicator light Error m essage sent via radio Indicator sentin cab. via radio Error link message to wayside to application Loss o f status indicators in cab. alert m aintenance personnel. How Detected/Response Detected cabby warningand loss signal of braking in power. Detected routineby inspection calibration. and link to waysidem aintenance to alert personnel. ICEFM E AWorksheet stop train at low speed. should increase/decreasesystems toshould compensate. non-friction be maintained. braking Stopping distances Operator mEddy ust manuallycurrent braking applyeffective discineffective brakes. below below 20In km/hr.40em ergency,disc brakes.operator m Other ust manually systemsNone. applyare not Feedback sufficient from to wheel-speed sensorAssuming correctly,all other brakesystems Ablending TCare wfunctioning ill EBCw apply ill Uoccur brakesand asdiagnostic asnorm needed al. equipment Trainas long switches areas to manual operation. diagnostic. DAVID Control revertsotherwise to operator.unaffected. Braking system s Effect on Overall Braking System km/hr; Electrodynam ic braking m uch less functioning properly. unit in secondtrain. power Note,travel car however, without continues undergoingthat to train m onitor man ay autom not begin atic brake 3-9. Table D isc brakesa p p liedisproportionately d . The DAVID computers in constantlyeach and m onitoring each other. the trainconflicting Automatic diagnostic Overrides A TC and appliesLoss of manual brake control. Loss of prim ary brake statusdiagnostics. Effect on Braking Subsystem D isc brakes not automatically power carin and the ZEUm iddle S computertrailer car arebraking w ill not respondinform ation.to b r a k e s . indicators.power Backup car unitcontinues in other to relay a p p lie d . I m p r o p e r Calibration F a i l s O n Sends IncorrectS i g n a l F a i l s O f f F a i l s O f f Failure M ode F a i l s O f f "DAVID" (Power Driver’s BrakeV a lv e Car DiagnosticC o m p u t e r ) ICE— IntercityC o m Express p o n e n t (Germ any) (Electronic- Pneumatic ControlBraking Unit Changeover) P n e u m a t ic
3-47 B 2 S B 2 A 2 D D A 3 1 ) Y N 1 ) Y FS N N 2 ) Y 2 ) Y N Y 1 ) Y 1 ) Y FT Y N 2 ) Y 2 ) Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT 1) Driver may sense extreme 1) Unusual wear to brake pads Indicator insent cab. via Errorradio messagelink to wayside to How Detected/Response alert m aintenanceIndicator personnel. sentin cab. via radioalert Error mlink aintenance message to wayside personnel. to Electrodynam ic brakes are not Requires braking/manualemergencyb r a k eapplication s of deceleration.amount 2) of brakesUnusual wear tomay friction suggest being appliedl e v e l sat . optimum and discs.except 2) byUndetectable, inspection. Indicator in cab Effect on Overall Braking System Control revertsotherwise to operator.unaffected. Braking system s 1) Feedback system reduces Friction braking to Control revertsotherwise to operator.unaffected. Braking system s Substantial loss of braking. Feedback from accelerom eters should counter system increases Friction braking. Regenerative this effect with little change in brake operation. compensate for over-braking.and Eddy Current2) Feedback braking should already be Electronic Braking Control Unit m ust sense that m a x im iz e d . train is not decelerating properly and decrease b r a k i n g . ICEF M E AWorksheet (cont) 3-9. Table 1) Fails to activate 1) Brakes over-applied. 2) Effect on Braking Subsystem DA VID computers in each power 1) Brakes over-applied. Unusual N o reduction in brake power. car are constantlytrain and eachmonitoring other.conflicting the Automatic diagnostic The ZEU S computer in the braking w ill not respondinform ation.to m iddle trailer car and the electrodynamicto activate brakes.Fails Friction to 2) activate Failsbrakes. Eddy-Current 3) Brakes under-applied. wear to brakeBrakes pads under-applied. and discs. 2) b r a k e s . Brakes lock. W heel skids, and increasingl o c k i n gchance . for future possibly causing wheel damage F a i l s O f f s ig n a l Failure M ode Fails to send s ig n a l t o Sends IncorrectS i g n a l s ig n a l t o Sends incorrect Electrodynam ic Sends incorrect Fails to detects lip b r a k e s P n e u m a t ic s ICE—IntercityC o m Express p o n e n t (Germany) Page 2 of 6 "ZEU S" computer(Diagnostic in middle MGS) trailer car)(M GS) ElectronicControl Braking Unit (H SM - (Anti-skid) Device W heel-slip
3-48 B 3 S B 2 C C D N FS N Y Y Y Y N N FT Y Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Indicator in cab or by How Detected/Response Indicator in cab (or lack Slight differenceeither side inrequire ofpressure blockage. shuttingcompressor. on offM ay one Blockedresult inlines engagedsom e brakes ast o pressure s yremaining s t e m . is returnedBrakes appliedGauges autom show atically. loss of pressure. Indicator in cab. inspection. t h e r e o f ) feeding individual tracks w ill Friction brakes utilized. Friction brakesIn em alone ergency, apply both D isc and Eddy In either case, loss of brake power requiresEm ergency braking m ay Frictionrequire use brakes of m ust provide m ost of the Clog may need to be removed to release disc are sufficient to safely stop the train Currentin brakes. Disc brakes alone are sufficient Effect on Overall Brakingincreasing Systembe braking. m aintained Braking at speeds distance underM agnetic45km/hr.may not Track Brakes. the train within required distances. None. Sam e levels of braking are available. None. Friction brakes will be fully applied. minimum required distance. to stop train in safe distance. Eddy Current braking force.nor Eddy Neither Current Regenerative braking is sufficientbraking to stop b r a k e s . , , brakes w ill help relieve wear on discs. ICEF M E AWorksheet (cont) 3-9. Table A ll disc brakes are applied. Loss of electrodynam ic braking requiring operation.m anual m echanical Electrodynamcar. Loss ic of Eddy CurrentCurrent brake subsystem.None. Aapply ir canbrakes. released,still beBrakes ventedhowcuts ever,cannotoff to pressureif be blockage from m ain line Effect on Braking Subsystemreducing braking power. Pneum atic braking off-line brakes operational brakesonly in"downstream" leadPossible loss of of break. entire Eddy to individual axle or calipers. Releases brake prematurely, (pipe blocked) Fail Open (leak) F a i l s to accept/producec u r r e n t Fails to canysignal (break in Fails Closed Detects slip when Failure M ode l in e ) none exists. Regenerative Etcctrodynainic Braking B r a k e P i p e ICE—IntercityC o m pExpress o n e n t (Germany) Page 3 of 6 (Anti-skid) Device T r a c t io n M otor/Generator Pneumatic (Air) Fibre-opticD aTrain t a B u s W heel-slip
3-49 A 2 S D A 3 B 3 B 3 D C N FS Y N N N Y Y FT N Y Y 3 N Y Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Loss of power to that axle. How Detected/Response Indicator in cab. By inspection. Damage may be By inspection. By inspection. Gauges showBrakes loss cannot onceof pressure. applied.be disengaged Brakes applied. Low-Pressure o b v i o u s . indicator into cab.determine Requires cause. test (cont.) Effect on O verallTotal Braking lossthat of axle. ElectrodynamSystem axle Reduction if wheelaxles ic braking inlocks.must Friction be powerFriction increased braking at braking toFriction at com that at pensate. brakesotherEddy Currentm ust be brake applied system. with the help of Negligible effect on system as whole unless apply, feedback should signalBrakes em applied ergency in brakes order to quickly stop train many calipers are effected.t o a p p ly . If brakes doand not minim ize damage. N egligible unless many discsN o n e . are effected. Above 43 km/hr, the other brake subsystems assist in slowing train, m inim izing wear on disc In em ergency, otherdeceleration. braking system s contribute b r a k e s . to stopping train up to lim it o f allow able ICEFM E AWorksheet 3-9. Table 1) W heel held fixed. Damage to Braking power m ay be associateds liaxle, p . causing wheel Dissipation occurs in Effect on Braking Subsystem maintained.motor/generator Seizure of m ay seize the D isc Brakesystem inoperable. increasesaxles to braking Feedbackcompensate. at other wheel possible. 2) Brake pads None. Second reservoir in other motor/wiring.p o wLoss e r . o f brake Damage to brake pads. Loss of fail. 3) Excessive wear on disc. Pressure released; brakes applied. pow er carpressure can provide for entire enough train. air brake adhesion. F a i l t o Bearing failure,axle seizes. accept/dissipatee n e r g y Fail Closed(brakes applied) Failure M ode Fails to hold F a i l s O p e n Fail Openb r a(no k i n g ) F r a c tu r e d p r e s s u r e M otor/Generator ICE—IntercityC o m Express p o n e n t (Germany) Page 4 of 6 Brake Discs Main Air Reservoir Disc Brake Calipers Catenary forDissipating E nBrake e r g y T r a c t io n (C o n tro l/ ( p e r C a r ) Pressure M onitoring Distributor) Valve
3-50 B 3 S D D B 3 Page 5 of 6 N N FS Y Y Y FT Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Indicator in cab. By inspection. High pressureCom pressorlight c aon. b . status indicator in How Detected/Response Low-pressureCom pressorindicator failure in cab. indicator. (cont.) Braking power reduced in em ergency situation. Effect on OverallN egligible Braking if ventingSystem occurs Inat emanother ergency,all valve. valves negligible canhave slow failed.above vehicle Electrodynam45 km/hrto about unlessN o n10 ic e . brakes km/hr. M agnetic Brake application mshould ay be slowslightly train. delayed Overall while effect should be This is anonly emergency aftera pall p lie m dother easure . brake which subsystem is applied s are fully Response time suffers. track brake m ay be required. venting excess air. negligible. Electrodynam ic brakes ICEFM E AWorksheet 3-9. Table of m agneticc a r . track braking on that Electropneum atic changeover Effect on Braking Subsystem other valves, brakes w ill not be application.Frictiondisengaging. brakes not brake pads. Problem is with Substantial (if not com plete) loss Second comOne pressorcomenough pressor initiated. pressurealonecom pressors can forlost supply train.fail - brakes andIflonger both pressure are to and applied.recharge is release Takes air brakes. reservoirs M ay cause Pressure excessregulating airacceptable valve to m vents aintain level. pressure calibration at m ay be effected. Pressure notvalve. released Unless at bleedingthis a p p lie doccurs . at brake release, not premature wear to discs and No m agneticattraction/fails to Fails to provide Supplies too Fails Closed make contact p r e s s u r e m uch pressure Failure M ode surface with rail) ( p e r C a r ) Rotaty-ScrewC o m pAir r e s s o r ICE— IntercityC o m pExpress o n e n t (Germany) (C o n tro l/ Distributor) Valve W ear Plate (contact Pressure M onitoring
3-51 S B 3 FS N FT Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT How Detected/Response Indicator in cab. Unusual wear to disc brakes,inspection/diagnostic. result of Effect on Overall Braking System A TO senses train not slowing down, increases braking effortb r a k e sin . electrodynam ic and disc ICEF M E AWorksheet (cont) 3-9. Table Effect on Braking Subsystem Loss of Eddy Current braking. Failure M ode F a i l O f f ICE—IntercityC o m pExpress o n e n t (Germany)Eddy Current Drake Sy&tera4 Page 6 of 6 Eddy CurrentSystem Brake (MCoils, agnetic switching equip., etc.) 1. If train is in motion. 3. If few axles affected. 2. Due to redundant unit, operator action is not required. 4. Eddy current brakes not yet available in revenue service. A truck would be fitted with either eddy current brakes or m agnetic track brakes, not both.
3-52 V. 3.4 TGV ATLANTIQUE
3.4.1 Description of Trainset
The French National Railway (SNCF) Train a Grande Vitesse (TGV) represents a French high-speed rail technology that has been in successful service operation since 1981. To date, SNCF has transported over 160 million people on two operating TGV lines with an impressive safety record.* The TGV Sud-Est (TGV-SE) has been in revenue operation since 1981 at a maximum speed of 270 km/h (168 mph). Planning for the TGV Atlantique (TGV- A), began in 1978 and construction was started in 1985. The TGV-A provides high-speed service between Paris and Brittany and Bordeaux. Over sections of dedicated right-of-way, the train operates at normal service speeds of 300 km/h (186 mph). On conventional lines, the speed is restricted to 220 km/h (137 mph). Maximum gradients on these lines are 2.5 percent (1 in 40), and less than the 3.5 percent (1 in 28.5) on the TGV-SE lines to Lyon.
The TGV-A consists of the following equipment:
• two power cars (two 2-axle bogies each, 8 axles total at 17 metric tons/axles),
• two transition cars connected by articulated joints (one 2-axle bogie, one shared, 2-axle bogie each, 6 axles total at 17 metric tons/axle, maximum under any operating condition), and
• eight trailing cars connected by articulated joints (2 shared bogies each, 16 axles axles total at 17 metric tons/axle, maximum under any operating condition).
The TGV-A trainset weighs 475 metric tons (523 tons) with a normal passenger load. The trainset length is 237.59 meters (779 ft-6 in). This trainset includes many technological advances including: 1) three-phase synchronous traction motors, 2) carbody mounted traction motors with a unique sliding tripod transmission, 3) articulated intercar connections forming a fixed consist arrangement, 4) very high-speed stucks with a unique pneumatic secondary suspension, and 5) a computerized communication network for distributed train control.
3.4.2 Braking System Design
The braking system of the TGV train has been described in general in several publications [Refs. 17-20]. Details of the braking system on the TGV train for NEC demonstration was provided in a proprietary “white paper” prepared by GEC Alsthom/Bombardier Inc. [Ref. 21]. The TGV train has an electro-pneumatic two-pipe brake system conforming with UIC standards. A key feature of the braking system is the control, from a brake demand, on a
In a recent incident, an undetected underground WW1 bunker collapsed beneath the track, causing a 7-meter-long hole. A TGV travelling at about 295 km/h passed over the hole, which derailed the last four cars of the train. In braking to an emergency stop in over 2 km, the four cars remained upright and only one of 200 passengers was slightly injured.
3-53 per-truck basis. To achieve this, each truck has its own pneumatic brake control panel. In addition, wheel slide protection is provided on a per-axle basis for the trailer trucks. Other salient features of the brake system include 1) fixed-consist operation, 2) on-board monitoring and diagnostics, 3) advanced train control systems, and 4) a failsafe, fault-tolerant design.
Major components of the TGV brake system are described below.
Major Braking Components
The TGV braking system consists of a combination of rheostatic (dynamic resistive), electro pneumatic, and friction braking which are blended automatically. In the power car, the proportion of electric brake effort provided varies with speed and the brake demand. These are independent systems for each driving bogie on the power cars. Normally, the dynamic brake is powered from the catenary, but there are backup batteries for each driving truck. Resistor grids are located on the roof of power cars. The power is not fed back to catenary, but always dissipated into heat, avoiding loss of dynamic braking in the event of catenary power loss or rejection.
The pneumatic friction brake system powers all axles of the trainset. These brakes are controlled by commands transmitted through brakepipe pressure changes, complemented by an electro-pneumatic train line for faster response throughout the length of the train. The main features of the friction braking are:
• Two double disc brakes (eight brake cylinders per truck) and four non-ventilated discs per axle on non-driving axles, with alloy steel discs and sintered metal linings (pads) to withstand higher temperatures,
• Tread brakes on the wheels of driving bogie,
• Pneumatic power (UIC standards) via brake pipe, complemented by electro pneumatic valves and trainline for faster response,
• Independent and redundant controls per bogie, including microprocessor-based anti-skid system which controls each axle independently,
• Spring loaded, air released parking brakes on one axle per driving bogie, with no hand or parking brakes on other car axles.
Braking is blended automatically by the computer to maximize dynamic braking. Blending will use the dynamic brake up to its maximum power level 1620 kW/truck, or about 6480 k/W trainset) and distribute the remaining braking power to the trainset friction brakes. Tread brakes on the powered bogies are used only as the train nears a stop, or as a backup to the dynamic brake in case of a failure.
Uniform distribution of a command brake pipe pressure reduction is achieved by the electro pneumatic (EP) valves for each truck. Pressure is modulated at additional EP valves on each axle by the electronic anti-skid control units. A separate EP valve on the truck changes
3-54 braking effort level as a function of train speed. Electrical speed sensors provide the axle speed signals for both slip control and braking level functions.
3.4.3 Braking System Performance
Technical Specifications
A full train weighs approximately 475 metric tons (523 tons). A maximum emergency deceleration rate of 1.2 m/s2 (0.122 g, 2.70 mph/s) is quoted for the trainset from 320 km/h with a stopping distance of 4.38 km in 98 seconds. The operating deceleration rate is 0.33 m/s2 (0.034 g, 0.75 mph/s) for a stopping distance of 11.91 km in 266 seconds. Typical braking distances to stop are given in Table 3-10.
Table 3-10. TGV-A Trainset Stopping Distances for Typical Conditions
Speed km/h (mph) Distance m (ft) Condition 180 (112) 1150 (3772) Dry rail, level tangent track, emergency .. braking, dynamic brake on batteries 270 (168) 2700 (8856) 300 (186) 3580 (11750) 230 (143) 2300 (7544) Wet rail, automatic sanders
For braking purposes, the following reduced adhesion levels are assumed: 8 percent at 300 “ km/h, 11 percent at 200+ km/h, and 15 percent from 200 down to 40 km/h. Brake cylinder pressure is modulated according to speed: 2.9 bar (42.6 psig) for speeds less than 215 km/h (134 mph), 2.3 bar (33.8 psig) for speeds of 215 km/h or higher for maximum service brake pipe reduction (1.5 bar, 22 psig) to emergency brake pipe reduction (three bar, 44 psig).
Diagnostics and Monitoring
The TGV trainset has an on-board detection, monitoring, and self-diagnostic system. Individual microprocessors on power and trailer car trucks monitor equipment, detect faults, and store fault code and circumstances for future maintenance. Fault codes are sent to the driver’s cab computers for display and transmission to other central computers, such as train control and maintenance facility computers.
Braking System Operation, Control and Safety Features
Operation and Control. The train operator (driver) controls acceleration/ deceleration by means of the traction controller wheel, which sets the intensity of the function (traction power
3-55 or rheostatic braking). A separate control sets friction braking through pneumatic and electro pneumatic control, blended with the rheostatic braking automatically by the computer to maximize dynamic braking.
The driver is responsible for normal on-board operational train control, assisted by microprocessor monitoring and display. The dynamic brake function is available to the driver through the traction-braking master controller. This controller permits the driver to apply power per brake to control train speed. A separate control allows access to the air brakes for the trainset via the brake pipe. When this control is used, the control computers will normally rely on dynamic braking with no reduction in brake pipe pressure until required for additional braking effort. This reduces friction wear. Separate microprocessors control traction-braking of each motor truck, providing the following functions:
• Distributes braking (dynamic has priority), • Monitors dynamic brake power dissipated, • Provides wheel slip control, • Detects, records, and displays faults such as brakes not released, truck running instability.
Separate microprocessors on each trailer car truck similarly provide wheel slip control in braking and fault detection.
Braking is also controlled through the driver’s automatic brake valve (ABV) through the electrical train line and EP valves, or through pneumatic control of the brake pipe directly. Independent from the ABV are additional brake control features. These include:
• Automatic Train Control (ATC), • Deadman control, • Emergency “punch” valves in the cab (two), • Emergency brake valves in cars T1 and T3 for crew use.
Passengers have no direct access to emergency brakes per se, but instead have emergency signals which alert the crew to problems.
Safety Features
Brake tests are initiated by the operator, automatically assisted by computer controls, data processing networks, and remote sensors (pressure, running stability, etc.). Automatic inspection and diagnostic systems check system status once per minute by car and bogie, and provide status read-out for the operator. Anti-skid functions on each axle are checked during each stop.
Speed reduction tables, which provide a matrix of maximum operating speeds for different combinations of brake failures, are used to define the allowed speeds as faults occur. For example:
3-56 • Failure of one trailer car bogie friction brake, plus one power car bogie dynamic brake is the limit for no speed reduction.
• Failure of four friction and four rheostatic (dynamic) bogie brake systems requires initiation of emergency stop.
The driver is required to notify Central Traffic Control of any combination of failures. An automatic train stop is initiated if operator exceeds speed limit (per signal aspect) plus 10 km/h. There is no override, and a full stop penalty is assessed.
Failsafe features of the TGV trainset, with more than 10 years of revenue service experience, may be summarized as follows:
• System complies with UIC standards,
• Vital functions are continuously and automatically monitored, including... brakes truck stability cab signalling traction drive equipment
• Monitoring functions are tested automatically at regular intervals,
• There is built-in redundancy in system components,
• There is information exchange between on-board computers and microprocessors and wayside installations,
• There is a standby computer (the auxiliary cab computer), and,
• The dynamic brakes are independent of catenary power.
t Braking System Effects on Vehicle, Guideway, and Infrastructure
The TGV trainsets do not use auxiliary emergency braking systems such as electro-magnetic friction track brakes or eddy current brakes. Future use of such systems is not addressed in any of the available documents. Effects on the guideway and infrastructure are therefore limited to maximum longitudinal wheel forces generated at the wheel/rail contact patch for the expected levels of adhesion. High dissipated heat levels will be generated at the dynamic brake resistor grids and at the friction brake discs. Much research and development has been applied in the design of high-temperature brake discs and pads to withstand these high temperatures without damage or failure.
No unusual electro-magnetic effects on signalling or control due to braking functions are anticipated from TGV operations.
3-57 D S C B 2 C D A 3 A 3 Y 1 Y 2 FS N 3 Y 2 Y N N Y FT N Y N Y N N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT H o wDetected/Response Computer senses failure, notifies notifies Computerfailure, senses operation andcontinues operator, computer. auxiliary with cab the via notified Operator stops. computer.Train control cab the via notified Operator mustcomputer.Operator control control cab via notified Operator computer. stops. Train utilize pneumatic control. brake utilize cab via notified Assumeis operator computer. opportunity. Maintenancecontrol first at taken action as available Emergencystill valves control cab via notified Operator Assume driver can isolate system Assumeisolate can driver reducedor speed at andcontinue failure. computer. continue andbrakes Must manuallyand stop failed isolate for defined limits speed within brakes. failed with operating Wheelslide indicated to driver. driver. to Wheelslideindicated dependingspeed of ondegree line backup. N oeffect. all for braking friction Unintentional all for available not braking Friction would train onthe brakes friction All wearbrakes on excessive in resulting Effect onOverallBrakingEffect System tracks. tracks. wheels. possibly and anddiscs control. no However, control. nois wthere slide. not release or would orapplied be release not Over application of brakes onone brakes of Overapplication axle. the for wheelcausing slide axle N o effect, continues to use EPuse to continues N oeffect, brakes. friction the for backupcontrol maT wheel waxles y experience o (2) Table 3-11. TTable3-11. G VF M E AWorksheet Effect onBraking Effect Subsystem Friction brakes not applied or applied not brakes all Friction for applied already if released tracks. train onthe brakes friction All wouldor be wouldrelease wearnot excessive in resulting applied Auxiliaty computercomes Auxiliaty on-line instantaneously. stays or applied brakes Friction tracks. all for applied N o wheel slide protection for the the for protection N owheelslide wearonwheels andexcessive rails. on brakes and discs and possibly possibly and anddiscs brakes on wheels. However,no control. nois wthere slip. Braking applied to axle is is axle to Brakingapplied slip. track. Wheel slide resulting in in resulting Wheel track. slide N o effect, continues to use EPuse to continues N oeffect, friction the for backupcontrol brakes. above desired braking level level braking abovedesired Thiscauses wheelslip. in resulting wearon wheelsandexcessive rails. Results in maintaining current current maintaining in wheel Results alleviating not level, brake Fails off Fails on Fails Fails incorrect incorrect Fails off output, on Fails Fails off with off Fails wheelssliding output with Fails Fails off Fails Failure MoFailure d e modulate the modulatethe cylinder brake pressure. failing to to failing (includes electric electric (includes (controls each axle axle each (controls per andEP valve axle) Computer(Assume it ElectroPneumatic (EP) ElectroPneumatic lines) signal T G YAtlantique— TrainGrandea (France) Vitesse Component Cab Driver’s 9 Pageof 1 independently, independently, sensor speed includes Passenger Car Control Control CarPassenger one of equivalent system) PneumaticControl BrakeControl BrakingControl Computer Control for Wheel for Control Protection Slide monitors the the monitors two track’s, trailer wheelslide axles,
3-58 S B3 D D D D D C N Page 2 of 9 of Page2 FS Y Y Y Y Y Y Y Y Y FT Y Y Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT H o wDetected/Response indication Assume receives operator than effort brakinglower of requested. Mat aoperate yhave to speed line reducedorspeed dependingfailure. onof degree AE to and 2switches failure senses future for failure andstores diagnostics. is nothing so available A E 1 still Wheel Slide Protection Control WheelProtection Slide Wheel Protection Slide effected. andstores failure senses Control diagnostics. future for failure for failure andstores failure senses EB to and switches failure senses future for failure andstores diagnostics. future for andstores failure senses diagnostics. Speed reduction beyond Speed reduction level desired. WheelProtection Slide ma control yoverworked.be If ma train, operator manually,excessive, y stop brake(s) failed isolate for limits speed within continue brake. failed with operation Wheel Slide Protection Control Control WheelProtection Slide diagnostics. future Control WheelProtection Slide Wheel Slide Protection Control Wheel Protection Slide Effect onOverallBraking Effect System axle. one of effort N oeffect. only but used, AEstill 1is N oeffect, backup ato as beavailable E Bwill A E 1fails. One track maOnemuch. too track brake y wearand brakes on ofOverheating componentspossible. Reduces available braking by the bythe braking Reducesavailable AE1. AE uses AE2. 1or N oeffect, N o if AEavailable bebackup for 2 will N oeffect. nobut A uses E signal, N oeffect, backup is available for AE. for available backupis Table 3-11. TTable3-11. G VF M E AWorksheet (cont.) (AE2 obtained via electronics electronics (AE2 via obtained A E 2 from adjacent track is used. used. Ais E track 2from adjacent AE1)independentof but used, A Estill 1N is oeffect, a as Ebeavailable only Bwill Effect onBrakingEffect Subsystem below is axle to Braking in applied resulting level braking desired axle the for nobraking reducedor control. failed the with associated (EB obtained via electronics electronics (EB via obtained backupAE1. to E B from adjacent truck is used. used. is E truck Bfrom adjacent nobut A uses Esignal, N oeffect, above is truck to Braking applied Wheelbut level, braking desired wheelslide. N o effect, uses AE uses AE2. 1orN oeffect, N o A E 1fails. independent of AE)independentof backup is available for AE. for available backupis prevents Control Protection Slide backup for AE 2 will be available if if backupAEavailable be for 2will signal Incorrect input input Incorrect signal input Incorrect signal signal. Fails with output output with Fails Incorrect input input Incorrect input Incorrect signal. output with Fails Incorrect input input Incorrect requesting brake requesting pressure cylinder open. requesting requesting Failure MoFailure d e thus vented, be to braking abovebraking required. level keeping the valve valve keepingthe EB EB AE A E 2 AE 1 (Motor Track)(Motor (MotorTrack) (Trailer Truck) (Trailer (Trailer Truck) (Trailer (Trailer Truck) (Trailer T G YAtlantique— TrainGrandea (France) Vitesse Component axle each (controls axle) Control for Wheel for Control Protection Slide per EPand valve Control and EPand ValveControl ChangingBrakeEffort speed (includes Level sensor) independently, independently, sensor speed includes
3-59 B3 S C B3 D D D N Page 3 of 9 Pageof 3 FS Y N Y Y Y Y 4 FT N Y 4 Y Y s Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Assume computer signals operator. Assumeoperator. computer signals H o wDetected/Response axle one of brakingfailed Continuewithout andisolate stop or axle, and continue within speed limits for for limits speed within andcontinue brake. failed with operation Computeroperator. signals manuallycan Operator decrease manuallycanOperator increase braking via traction control wheel control traction via braking pneumaticcontroller. brake and/or Computeroperator. signals braking via traction control wheel control traction via braking pneumaticcontroller. brakeand/or Computerpowermonitorsof andinformsoperator dissipation Computerswitches automatically changespower source automatically powerbrakingand distribution. of battery loss for the track. Repair track. Assumeoperator the for computer notifies loss battery of maintenance opportunity. first at this level. Increase friction braking friction Increase level. this computer via blending. required as then powerwhenfailure, senses Effect onOverallBraking Effect System bybraking friction Reducesavailable the effort of one track. one of effort the the for Toobraking mucomputer. c rheostatic hfailed the with onetrack powerbraking of Distribution Distribution of braking powerbraking of Distribution one track with the failed computer. failed the with onetrack wearfriction on excessive in resulting betweenmasystems be correct. not y To o little rheostatic braking for the the for braking rheostatic Tolittle o between masystems be correct not y brakes. mustbe distribution Brakingforce friction with weightedmoreall or offset to braking friction in Increase N o effect except that there will be nobe will there that except N oeffect lower rheostatic braking so that total total that so braking lowerrheostatic decreased. backup for rheostatic braking for the the for braking rheostatic backupsystem. for battery failed awith truck braking. Increased wear on friction wearonfriction braking. Increased brakes. marginally only is effort braking Table 3-11. T3-11. Table G VF M E AWorksheet (cont.) Braking applied to truck is below is truck to Brakingapplied Effect onBraking Effect Subsystem in resulting level braking desired Braking power for the track with track the Brakingpower for reduced or no friction braking for for braking nofriction reducedor control. Excessive weartheyExcessive onwheels as the failed computer will betoo computer will failed the not powerBrakingwill requested the trade assodated with the failed failed assodatedthe with trade the high and distribution between anddistribution high masystemsbraking incorrect. ybe Brakingpowerthe besupplied. for computer will failed the with track andtoo'lowdistribution be betweenmasystemsbraking ybe incorrect. potentially slide. potentially Decrease or loss of rheostatic rheostatic of loss Decreaseor power. battery Switchto braking for the truck. the for braking be will there that except N oeffect system. no backup for rheostatic braking rheostatic nobackupbattery for failed a with track the for Fails with output output with Fails requesting requesting Fails, braking is is braking Fails, abovelevel Failure MoFailure d e belowbraking required. level requested. is braking Fails, belowlevel requested no including Inability to Inability dissipate N opower braking. energy/heat N o battery power N obattery T G YAtlantlque— TrainGrandea (France) Vitesse andEPControl Valve speed Level(includes sensor) MotorTruck Traction Motor Traction Computer Control Component Changing BrakeEffort Catenary PowerCatenary Battery and Battery Battery and Battery ChargingSystem RheostaticBraking (2) Grids Resistor
3-60 S B3 A 2 B3 B3 D C D N N N Y 2 FS N Y Y Y« Y Y Y N FT N Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT slide. Stop train, manually isolate manually isolate train, Stop slide. brake. failed with operation Maintenanceand dissipation. Operator notified via the cab the via notified Operator computer. control H o wDetected/Responsc of Computeroperator signals speed within Continueoperation with operation for defined limits brakes. failed wheelof Computeroperator signal continue possible, if failure for limits speed within operation Computerpowermonitors inspection. Computerpowermonitors Maintenanceand dissipation. Computerpowermonitors Maintenanceand dissipation. inspection. Computerpowermonitors Maintenanceand dissipation. inspection. braking loss for the track. track. the for loss braking inspection. Unintentional braking for all friction friction all for braking Unintentional Effect onOverallBraking Effect System trnck. this for braking N orheostatic one for wheelslide Unintentional blower. of replacement early Eventual braking rheostatic of Overloss time blower. of replacement early Eventual for capability Overdecreased time traction for reducedability as well brakes. Effects entire trainset. entire brakes. Effects Increased braking necessary fromnecessary or braking Increased rheostatic possibly trucks, the other of blending via both or friction brakes. motortruck. resistors. overheating the as track the for braking rheostatic motor. of loss power. Potential potential for the track associated with with associated track the for potential Table 3-11. T3-11. Table G VF M E AWorksheet (cont.) slide protection control attempts to to attempts control protection slide wearonblower. Increased More andheat wear motors on motor. (2) in Could result dissipation for applied stays or Brakeapplied alleviate wheel slide. alleviate and resistors of heating Increased wearon blower. Increased Effect onBraking Effect Subsystem truck the for braking N orheostatic in failed motor. failed in fails brakes. valve If friction all Unintentional wheel slide. Wheelwheelslide. Unintentional failure. resistor for potential associated with the failed traction traction failed the with associated gradually be applied as the pressure pressure the as beapplied gradually brake the becomesin drop larger pipe. motor. partially open, brakes will will brakes open, partially Fail off/low Fail Fail on/high Fail off/low Fail Fails open Fails axle seizes. axle on/high Fail Does not produceDoesnot Bearing failure, failure, Bearing Failure MFailure o d e to current in dissipate grids. resistor blower) (powered by current (poweredbycurrent blowers) (3 Blowers for Resistors Resistors Blowers for grids) resistor to Blowers for MotorsBlowers for (poweredbycurrent (1 T G VAtlantique— TrainGrandea (France) Vitesse 9 Pageof 4 Trailer TruckTrailer Electropneumatic ValveApply . to resistor grids) resistor to Component Traction Motor (2) Traction
3-61 I S B3 B3 C C C B3 FS N Page 5 of 9 Pageof 5 N Y 7 Y Y 2 N FT Y 4 Y 4 N8 N N Y 4 S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT H o wDetected/Response Operator notified via the cab the via notified Operator computer. brakes. control Continue failed within for limits speed brakes. failed for limits speed Operator notified via the cab the via notified Operator computer. control Continue within Operator notified via the cab the via notified Operator operating for defined limits speed brakes. failed with control computer. Manuallycontrol isolate within and continue brakes failed computer whichcontrol cabsends of low Computeroperator signals considered when braking is applied applied when considered is braking brake failed for limits speed Pressure sensor signal transmits to to transmits signal sensor Pressure operator. to Main information pressure increase opensto reservoir Compressor line. mainreservoir in on. turns via pressure restore ads to operator compressorandreservoirs. Computer monitoring notifies Computernotifies monitoring is Thenumberoperator. failures of is braking suffident ensure numberto fail, sufficient If available. mustbefollowed. operation pressure. If braking not desired, desired, not braking If pressure. - Effect onOverallBraking Effect System the for available not braking Friction failed the assodatedwith truck trailer valve. for available not braking Fridion valve. trailer track assodated with failed failed assodatedwith track trailer trailer the for Once applied brakes track assodated with the failed valve, valve, failed assodatedthe with track bereleased. cannot they fridion apply unableto Potentially and have mainline reservoirs trailer all for applied is brakeFridion tracks. anddriving brake for all friction brakes if all all if brakes friction all for brake pressure. insuffident Loss of friction braking for disc disc for braking friction Lossof assodated with failed brake cylinder. brake assodatedfailed with Table 3-11. T3-11. Table G VF M E AWorksheet (cont.) Effect onBraking Effect Subsystem Brake not applied or released if if released truck or applied Brakenot trailer the for applied already valve. failed the with associated Brake not applied, or released if if released trade or applied, Brakenot trailer the for applied, If already valve. failed the with brake open, associated partially fails valve unable or released be gradually will Once brakes applied for the trailer trailer the for Once applied brakes to be applied as the pressure pressure the as applied be to pipe. brake the in increases Applies friction brake. friction Applies truck assodated with the failed failed assodatedthe with truck bereleased. cannot they valve, after pressure reservoir auxiliary cylinder. Loss of friction braking for disc disc for braking friction Lossof Potentially unable to recharge recharge to unable Potentially application. brake assodated with failed brake assodatedfailed with Fails closed Fails Failure MoFailure d e open Fails L o wPressure L o wPressure Fails closed Fails Fails no pressure nopressure Fails cm disc brake cmdisc Component Electropneumatic Brake Pipe Line PipeBrake Electropneumatic ValveRelease T G VAtlantique— TrainGrandea (France) Vitesse ValveApply Brake Cylinder (8 per (8 BrakeCylinder MainLine Reservoir truck)
3-62 B3 A3 S A 3 B3 B3 B3 N N N N FIS N N Y 4 N Y 4 N YJ FT Y 4 S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Computer monitoring notifies Computermonitoringnotifies power.braking lost offset maintenancevia andDetected maintenance via andDetected maintenance via andDetected computer signals failed inspection, isolate train, Stop operator. with operation for limits speed MainComputeroperator. feed signals open to andline reservoir H o wDetected/Rcsponse to train Operatorstops operator. maintenancevia andDetected friction other Increase inspection. to rheostatic increase and/or braking friction other Increase inspection. power.braking lost offset to computer signals inspection, friction other Increase operator. power.braking lost offset within manually,continue brake(s) brake. failed normal to reservoir auxiliary Compressor pressure. to on turns main reservoir. fill isolate failed brakes, speed limits limits speed brakes, failed isolate mustbe operation brake failed for followed. to rheostatic increase and/or braking to rheostatic increase and/or braking Brake associated with failed caliper is is caliper failed with Brakeassociated in Results applied. constantly Friction brake applied for disc disc for applied brake Friction by25 axle % track onetrailer by<25 axle % track onetrailer by2 5axle some %or track onetrailer fails partially 25than amount %if less open. friction apply to unable Potentially auxiliary the with associated track lowpressure. with reservoir Effect onOverallBraking Effect System cylinder. brake failed with associated power braking on Reducesfriction power braking on Reducesfriction power braking on Reducesfriction will applied, already if or, brake braking whenrequested. braking not braking ■ release friction brakes for the trailer trailer the for brakes friction release ■ Table 3-11. TTable3-11. G VF M E AWorksheet (cont.) Brake constantly applied to disc disc to applied Brakeconstantly caliper. failed with associated wearExcessive and/or brakeson possible. overheating some25thanamount %if less Potentially unable to apply friction friction apply to unable Potentially trailer the for brakes friction release auxiliary the with associated track lowwithpressure. reservoir one trailer truck axle by2 axle 5 truck % onetrailer by<2 axle truck 5 % trailer one powerbraking on Reducesby2 friction axle 5 truck %or trailer one Effect onBraking Effect Subsystem disc for applied brake Friction brake or, if already applied, will will applied, already if or, brake Reduces friction braking powerbraking on Reducesfriction open. fails partially associated with failed brake failed with associated Excessivewear on brakes cylinder. possible. overheating and/or Reduces friction braking powerbraking on Reducesfriction Fails closed Fails lowwith Fails Fail openor Fail slightly open slightly Fails full pressure pressure full Fails pressure on brakes on Missingdisc W o r ndisc Failure MFailure o d e Auxiliary Reservoir Auxiliary Caliper Disc (4 discs per axle) per discs (4 Disc T G VAtlantique— TrainGrandea (France) Vitesse Component per (8 BrakeCylinder 9 of Page6 truck)
3-63 S C D D C C D C Y Y Page 7 of 9 ofPage7 FS Y Y Y Y Y N FT Y N Y N Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT H o wDetected/Response of Computer operator signals compressor Assumeoperation. emergencyuntil applied brakes and notified Assume automatically. is operates operator valve relief Compressor^)to off beshut can Computer signals operator. Computeroperator. signals recharge Compressor to on turns reservoir. Assume operator is notified and notified Assume is automatically. operator operates valve relief to off beCompressorcanshut (s) Assumehas reservoir. of driver also. cab pressure can be reestablished, if if bereestablished, can pressure possible. up. build pressure further prevent Gauges in cab indicate low pressure lowpressure Gaugesindicate cab in in compressor of operation indicator andmaintenance should Inspection first at Repair failure. valve detect Maintenance and inspection checks. Maintenance andinspection prevent further pressure build up. build pressure further prevent maintenanceopportunity. Effect onOverall Braking Effect System is valve Assumerelief pressure available on mainon reservoir. available Potentially unable to apply or release release andor apply to unable trailer Potentially all for brakes friction motortrucks. release andor apply to unable trailer Potentially all for brakes friction is valve Assumerelief pressure motortrucks. onmain reservoir. available fromventedmain reservoir is Airmain in lowpressure in of resulting application in resulting reservoir running excessive or brakes friction result. will both compressorsor of seconda requires This N oeffect. contamination and possible corrosion. andpossible contamination failure for this failure to haveany to failure this for failure impact. Wearoncomponents. System Table 3-11. T3-11. Table G VF M E AWorksheet (cont.) High pressure builds in main in builds Highpressure Effect onBraking Effect Subsystem reservoir. release friction brakes for all trailer or apply to unabletrailer all Potentially for brakes friction release Mmotorand trucks. a ybeoffset by second compressor in other bysecondother compressor in locomotive. release friction brakes for all trailer or apply to unabletrailer all Potentially for brakes friction release Mmotorand trucks. a ybeoffset main in builds Highpressure Air is vented from ventedmain reservoir is Air mainin low pressure in of resulting application in resulting reservoir Mandsafety R Soverpressurization by second reservoir in other other in bysecondreservoir locomotive. reservoir. friction brakes or excessive running excessive or brakes friction result. bothwill compressors or of combinationa of If N oeffect. for wouldnoberelief overpressurization. valve failing closed occurs, there there occurs, closed failing valve time. over corrosion Wearoncomponents. Component Fails to provide provide to Fails Fails by providing providing by Fails Failure MoFailure d e enoughpressure too mutoo cpressure h low with Fails high with Fails Fails open Fails closed Fails pressure pressure Fails with air too too air with Fails wet T G YAtlantique— TrainGrandea (France) Vitesse Main(2) Reservoir Component Compressor(2) Main Reservoir Safety MainSafety Reservoir Pressure Valve Pressure Air Dryer(2) Air
3-64 B 2 B3 C B 2 C A 3 S Y Y N N N N FS Y 11 N Y" N Y 4 N FT S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Computer signals operator of need of operator Computer signals emergency brakeapplies Operator offset lost braking power. braking lost offset maintenanceand via Detected failed isolate train, Stop operator. with operation for limits speed control the via notified Operator computer. position. Mustsystem closed recharge to valve andrestore begunBrakingnot byapplication valve. Apply secondvalve. first of control the via notified Operator computer. position. Mustsystem closed recharge to valve andrestore emergencyapply to brake. punchvalve. via Detected via maintenanceand via Detected to computer signals inspection, friction other Increase operator. computer signals inspection, within continue manually, brake(s) brake. failed H o wDetected/Response braking and/or increase iheostatic to to iheostatic increase and/or braking still be applied. be still emergency for Unintentional braking cars. all Emergency automatically not braking emergencyapply informed to brake. Brake associated with failed tread tread failed with Brakeassociated brakes. wearontread andexcessive emergency for Unintentional braking cars. all Needremainingemergencyapply to is operator as delay Slight applied. brake is constantly applied. Results applied. constantly is brake whenbraking not in braking wheelslide of Potential requested. punchvalve. Emergency canbrakes Reduces friction braking powerbraking on Reducesfriction by25 axle motorone some % track or fails 2partially than 5amount %if less open. Effect onOverallBraking Effect System Table 3-11. TTable3-11. G VF M E AWorksheet (cont.) Unable to apply emergencyapply Unable to brakes Brake applied or stays applied for for applied stays or Brakeapplied Brake applied or stays applied for for applied stays or Brakeapplied emergencyapply Unable to brakes time. a at fails one via the valve. the via the train. the oveiheating. train. the valve. They the are via assume only that independentso some25than amount %if less Brake constantly applied to wheel to applied Brakebrake. constantly tread failed with associated Wandwheelsma e atreads on brakes y r as well as result one motor truck axle by2 axle 5motorone % truck or Effect onBraking Effect Subsystem powerbraking on Reducesfriction open. fails partially Fails open Fails closed Fails Fails open Fails closed Fails Fails closed Fails slightly open slightly Fail openor Fail FailureMode (activated byspeed (activated deadman or control, Electropneumatic ValveDeadman km/hr10 if control, suppression limit, over control) EmergencyBraking10 Valves(2) Operator Access EmergencyPunch 30km/hr or emergency30km/hror T G VAtlantique— TrainGrandea (France) Vitesse Component MotorTruck’ 9 Pageof 8 Tread Brakes (in place place TreadBrakes(in of brakes disc of only truck) trailer 3-65 D S D B 2 D Y Page 9 of 9 of Page9 FS Y N Y 12 Y FT Y Y" Y 12 S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT H o wDetected/Response electromechanical via Detected in failure brake rheostatic sense proceedwith relays which the case relays, independent of electric, that that electric, independentof relays, all emergencyis that braking friction braking. friction control the via notified Operator computer. position. Mustsystem closed recharge to valve andrestore Crewemergencyapply to unable emergencyapply brakes. Assume brake. Crew must contact driver to to brake. Crew driver must contact emergencywarranting condition computer. Not detected except by increased byincreased except Notdetected computer unless distance stopping braking is signalled to operator via via operator to signalled is braking are operating. are monitors to what degree the sanders sanders what the degree monitorsto Effect onBrakingOverall Effect System braking. Friction N orheostatic braking increased to ma to x iincreased mbraking u as mand increased braking trucks other emergency for braking Unintentional necessary, if available. if necessary, cars. all emergencyof application Delay in brakes. distance stopping Increased Table 3-11. TTable3-11. G VF M E AWorksheet (cont.) Effect onBrakingEffect Subsystem truck the for braking N orheostatic Motor Traction failed the with Brake applied or stays applied for for applied stays or Brake applied emergencyapplyUnable to brakes Control Computer.Control the train. the via the valve. the via Increased stopping distance stopping Increased Fails to provide to Fails Failure MoFailure d e braking. rheostatic Fails open Fails closed Fails Dsand not o sufficiently T G VAtlantique— TrainGrandea (France) Vitesse Component Traction Motor Traction Computer Control Emergency (2) Valves CrewAccess Control of motor truck motortruck of Control Sanders (automatically (automatically Sanders Protection Slip >30km/hr) speeds for initiated by Wheelby initiated 3-66 Table 3-11. T3-11. Table G VF M E AWorksheet (cont.) . Computer increases other braking. other Computer. increases A. Unless reservoir. B Auxiliary P canrecharge 1. 1. Backupcomputer. 11. valve. must11. another Operatorapply distance. stopping in unexpectedincrease in 12. M a yresult 10. Includes means to apply the friction and rheostatic brakes that are both utilized, if possible, in emergency situations. Capable of stopping with only friction brakes. friction only with stopping Capableemergencyof in situations. possible, if utilized, both are that brakes andrheostatic friction means the apply 10. Includes to 2. Even though this failure results in the friction brakes being applied, this failure ma y not be failsafe if it occurs at high speeds. high at occurs it if ma failsafe be ynot failure this applied, being brakes friction the in results failure 2. Eventhoughthis byoperator. 3. Redundantapplied becan pneumaticcontrol 8 here. noted as except truck 9. Sametrailer as 6 4. If fewfailures. 4. If brake. 5. friction Computer increases 7. Brake applied only for this track. Even though this failure results in the friction brakes being applied, this failure ma y not be failsafe if it occurs at high speeds. high at occurs it if mafailsafe be not y failure this applied, being brakes friction the in results failure Eventrack. thoughthis this for only7. Brakeapplied 3-67 3.5 BRITISH RAIL INTERCITY 125 3.5.1 Description of Trainset The Intercity 125 is also known as the High Speed Train (HST). The IC125's were procured between 1976 and 1980 to operate at speeds up to 201 km/h (125 mph) over routes where conventional locomotive-hauled services were limited to 161 km/h (100 mph). The IC125 operates in fixed formations of either 7 or 8 MkHI trailer coaches with a Class 43 diesel-electric locomotives (power cars) at each end. These locomotives are each powered by a 12-cylinder, 1680 kW (2250 hp) diesel engine. In tests, the prototype trainset achieved a top speed of 230 km/h (143 mph). There are a total of 90 1025 formations in service, which operate over the following non-electrified routes: London-Bristol-South Wales London-Bristol-Penzance London-Derby-Leeds Edinburgh-Derby-Bristol-Penzance The IC125 is also used to operate a limited number of services over partially electrified routes between: London-Crewe-Holyhead London-Edinburgh-Invemess London-Hull Manchestef-Boumemouth Standard British Rail air brakes are used on the trainset, with the system designed to stop the train from 200 km/h in distances slightly less than existing locomotive-hauled trains at 160 km/h within the existing signalling blocks. 3.5.2 Braking System Design The Intercity 125 vehicles are fitted with a two-pipe Automatic Air Brake system. The braking equipment is supplied by Davies and Metcalfe and Westinghouse Brakes. Class 43 Power Car The power car has two graduated apply and release distributors connected to the Automatic Air Brake Pipe (ABP). Each distributor has a dedicated reservoir charged via a check valve from the vehicle’s Main Reservoir Supply (MRS). The output from each distributor supplies one of the bogies on the power car. The bogies are fitted with wheel mounted brake discs using air operated actuators fitted to calipers acting on non-asbestos brake pads. In parallel with the disc brakes, the bogies are fitted with air 3-68 operated tread brakes using cast iron brake blocks. The tread brakes incorporate an air release spring apply parking brake. The power car is also fitted with the BR Mark 2 WSP system, which operates on an individual wheelset releasing both the disc brake and its associated tread brake. The power car is fitted with a single continuously driven compressor charging the local MRS to a nominal 10 bar (145 psig). The train's MRP is charged via a pressure control valve to a nominal seven bar (102 psig). In the event of a compressor not running (power car shut down), the MRS can be charged to seven bar from the other compressor (in the second power car) via the MRP. The power car controls the ABP by either a Davies and Metcalfe E70 brake control unit or a Westinghouse DW2 brake control unit. The brake control unit is connected electrically to the driver brake controller via the train brake control wires. Class 43 Power Car Major Components Air Compressor and Delivery Systems. A single two-stage compressor is fitted supplying air via a check valve to the Main Reservoir supply. The pressure in the MRS causes an unloader to operate upstream of the check valve when the MRS reaches 10 Bar. The system is protected by a safety valve set at 10.7 bar (155 psig). The air is cooled and fed to two externally mounted main reservoirs. Condensate is removed by automatic drain valves. The power cars are not fitted with air dryers. For winter operation antifreeze is introduced into the air system. Distributors. The distributor has the characteristic of a graduated apply-and-release unit with a similar operation to a “UIC” unit. Brake Actuator/Caliper System. The brake actuators have integral slack adjusters to maintain the required pad-to-disc clearances. A non-latching resetting mechanism is included to allow the renewal of brake pads. The caliper pad holders are fitted with 500 cm2 pads utilizing the UIC style dovetail attachment. Retention of the pads is by means of a sliding gate which is latched when inserted in the pad holder. Tread Brake Unit. This is a twin unit mounted on the bogie acting independently on each wheelset. Each unit contains the service brake cylinder, which is air applied. The output force is taken through an integral slack adjuster to maintain the required block wheel clearance. Resetting the adjuster allows the changing of the single brake block, which is retained by a key through the holder and block. Brake Control Unit. The Air Brake Pipe Control signal, which is derived from the train brake control wires, is fed to a relay valve to charge/vent the ABP. The ABP can only be charged if the feed cut off valve is energized. 3-69 The method by which the control signal is generated depends on which manufacturer's equipment is fitted. The Davies and Metcalfe E70 uses electronically controlled Electro- Pneumatic (EP) valves monitored by pressure transducers to produce the appropriate pneumatic control signal corresponding to the brake demand train wire signal. The Westinghouse DW2 uses the train wire signals to switch pressure signals into a multi- diaphragm unit, which uses the different diameters of the enclosed chambers to produce the appropriate pneumatic control signal. The output pressure from the E70 and DW2 units are the same for all the braking steps and can operate together on the same trainset. Mkm Trailer Coach The Mkm vehicle has a single “UIC” style graduated apply-and-release distributor which is connected to the automatic air brake which is continuous throughout the train. The distributor has a dedicated auxiliary reservoir, which can be charged via the distributor from the ABP. Normally the main reservoir pipe (MRP) will charge the auxiliary reservoir at seven barvia a check valve thus forming the two-pipe system. The distributor supplies air pressure to the brake actuators. These are fitted to bogie-mounted brake calipers and apply the non-asbestos brake pads to the wheel-mounted brake discs. The air pressure in the actuator can be varied depending on braking demand and the load in the vehicles. The Mkm vehicles are fitted with BT10 air suspension bogies. An air suspension pressure output signal is fed into a variable load relay valve in the brake system. The Mkm vehicles are fitted with BR Mark 2 Wheel Slide Protection (WSP) equipment which operates on a local vehicle basis acting on individual wheelsets. Mkm Trailer Coach Major Components Brake Module. All the equipment associated with the braking system and the air suspension is fitted within a detachable brake module. Modules with Westinghouse equipment can be exchanged for those with Davies and Metcalfe equipment on a module-by-module basis. Distributor. The distributor has the characteristics of a “UIC” style graduated apply-and- release unit. Variable Load Relay Valve. Depending on the supplier, this is either a separate unit or is combined with the distributor. The output pressure from the distributor is fed into the relay valve, which has a variable position fulcrum. The output signal from the averaging valve sets the fulcrum position, thus the pressure to the brake actuator is proportional to the vehicle's load. A “no load” signal causes the variable load relay valve to operate in the tare condition. Averaging Valve. The averaging valve supplies a control signal to the variable load relay valve. This is derived by averaging the pressure in the two independent air bags of a single bogie. 3-70 J Brake Actuators/Caliper System. The brake actuators have an integral slack adjuster to maintain the required pad-to-disc clearance. A non-latching resetting mechanism is included to allow the renewal of brake pads. The caliper pad holders are fitted with 500 cm2 pads utilizing the “UIC” style dovetail attachment. Retention of the pads is by means of a latch which itself is captive to the pad holder. 3.5.3 System Operation and Control The principal operation of the air brake system is such that, after an initial reduction of pressure in the ABP sufficient to trigger the distributor, the amount of brake application is proportional to the reduction in the ABP pressure. The brake is released by recharging the ABP pressure. A reduction of 1.5 bar (22 psig) in the ABP pressure is required to produce a full service brake application. In an emergency brake application, the ABP falls to zero. The reduction or increase in ABP pressure is achieved by means of the brake control units at both ends of the trainset responding to the electrical signals derived from the driver’s brake controller in the operational cab. A reduction in the ABP pressure can also be achieved by the safety systems fitted to the trainsets. The driver’s brake controller has eight positions: Running, 1 through 6, and Emergency. The air brakes are fully released, provided none of the safety systems have operated, when the driver’s brake controller in the operational cab is in the running position. This energizes the three train brake control wires throughout the trainset allowing the ABP to be charged to the running pressure of 5.1 bar (74 psig). Moving the driver’s brake controller through the other positions causes the control wires to be switched in a binary code sequence such that when in the Emergency position all the control wires are de-energized. The two brake control units, one at each end of the trainset, respond to the status of the control wires resulting in even braking steps being achieved between Initial (Step 1) and Full Service (Step 6). While both control units are capable of venting the ABP to achieve the required brake step, the rear unit is prevented from recharging the ABP from its local MRS supply by a de-energized feed cut off valve. The ABP is thus vented from both ends of the IC125 in response to the driver’s brake demand, but can only be recharged from the leading power car. There is no direct connection between the train brake control wires and the vehicles' distributors. The distributors respond solely to variations in the ABP pressure. The characteristic of the distributors is such that the driver can continually vary the amount of brake demand throughout the brake application. Braking Control System Service and Override Capability. The braking control system uses electrically controlled brake units located in the power cars to control the pressure in the Air Brake Pipe. The brake control units respond to binary code signals generated by the driver’s brake controller in the operational cab. Three train lines (three-wire bus) are used to generate seven steps of brake 3-71 control. All lines need to be energized to release the brakes. The lines are progressively switched until in notch 7 (Emergency) they are all de-energized. The distributors on the vehicles respond directly to the ABP pressure controlled by the brake units. Application/increase in the brake force is initiated from both brake control units when reducing the ABP pressure. Reduction/release of the brake force is only achieved by the brake unit in the operational power car during recharging of the ABP pressure. The control system design is such that once any of the safety systems fitted to the train are triggered, the driver cannot override its application. Diagnostic Systems The IC125 is fitted with no diagnostics and only limited monitoring systems. The driver is presented with system pressure gauges from tappings on the leading power car and an indication of WSP activity on either power car. The coaches have a latched relay to indicate if WSP lockout has occurred. This is primarily to advise the maintenance staff of its operation. Under fault conditions the driver can isolate individual systems on the IC125 with the train proceeding forward at reduced speed or at line speed with additional footplate staff depending on which system/component has been isolated. 3.5.4 Safety Features The Power Car The power car's braking system is fitted with the following safety features: (i) Driver’s Safety Devices (DSD), Vigilance System and Speed Switch While the master controller is in either Forward or Reverse, the driver must retain pressure on a foot pedal. Once every 60 seconds, however, the driver must release and then reapply pressure to the foot pedal to prevent the ABP being vented. To prevent uncontrolled coasting with the master switch at Off or Neutral, a speed switch will apply the brakes if the train is travelling at over 5 km/h (3 mph). (ii) Automatic Warning System (AWS) The Automatic Warning System monitors the condition of the lineside signals. If green, the driver will hear a bell. However, on passing a signal not showing green, the driver will hear a horn. Failure to cancel the horn within three seconds will result in the ABP being vented. 3-72 (iii) Low Main Reservoir Pipe Pressure The pressure in the MRP is continually monitored to ensure that there is sufficient energy available to stop the train. Reduction in MRP pressure through compressor shutdown or failure of intervehicle hose connections will result in the ABP being vented, thus applying the train brakes. (iv) Brake Control Unit Charging The rate at which the Brake Control unit can recharge the ABP is restricted such that it is insufficient to overcome the loss of air from the ABP when one of the safety systems is activated. (v) Driver’s Brake Controller Emergency Position In addition to the train brake control wires being de-energized, the Emergency position causes the ABP to be vented directly. This feature is also available from the non-operational cab. (vi) Driver’s Emergency Plunger The cab is fitted with a plunger that also causes the ABP to be vented directly. Once operated it remains in a latched position until reset by a twisting action. (vii) Parking Brake Interlock Applying the parking brake system will also result in the ABP being vented. Trailer Coach The trailer coach's braking system is fitted with the following safety features: (i) Passenger Communication System Operation of any of the passenger alarm handles vents a pilot line which in turn causes the ABP to be vented by a pilot-operated exhaust valve. No override features are fitted to the MkITT vehicles. (ii) Air Suspension Charging Valve The air suspension system derives its air from the MRP, which is primarily for the brake system. The charging valve prevents the air suspension system being charged before the vehicles auxiliary reservoir has been charged to in excess of five bar. 3-73 (iii) Emergency Brake Valve The Guard/Senior Conductor's compartment is fitted with an isolating cock capable of venting the ABP. Train continuity is continually monitored by the brake system. Should the train divide, the ABP intervehicle couplings will part, venting the ABP in both parts of the train and thus applying the brake. The condition of the brake train control wires is monitored by the rear control unit, which will apply the brake in the event of a loss of the “Running” signal. In this case, it is permissible to isolate the rear control unit and continue at a maximum speed of 160 km/h. 3.5.5 Technical Specifications of the Braking System Speed Range The technical specification for the IC125 to stop from 200 km/h was set in the signaling distance originally established for the 160 km/h locomotive-hauled trains. The minimum signaling distance to allow 200 km/h running is thus 2,040 meters between the first caution signal (double yellow) and the red signal. The signaling distance can be greater than the minimum and was usually set when the signaling system was introduced. The minimum performance of the IC125 is such that it should not exceed 1,770 meters from 200 km/h. The safety margin is to allow for speedometer error and adverse rail conditions. Currently, 200 km/h operation is only being achieved on the London-to-Bristol route. Operational restrictions mean that the maximum speed elsewhere is 177 km/h (110 mph). The IC125 has to comply with all other speed restrictions applied to the routes. Wheel Slide Protection The BR Mark 2 WSP uses analog electronics to determine if the wheelset is sliding or rapidly slowing. Each wheelset sends a speed signal into the control unit, which compares the individual speeds and their rates of deceleration against the unit's internal performance characteristics. A dump valve venting the brakes on the appropriate wheelset will be activated whenever the WSP unit identifies that the wheelset is rapidly decelerating or sliding. The dump valve will reapply the brakes when the wheelset speed again matches the WSP unit's predicted vehicle speed or if the valve has been operating continuously for four seconds. In the latter case, the WSP unit assumes a fault on that WSP and locks out the dump valve for the rest of the stop or until all four wheelsets are operating within 10 km/h (6 mph) of each other. Retarding Force Each vehicle in the 1025 was designed to brake its own proportion of the train's mass. The braking of the power car's 63.5 metric tons (70 tons) mass is split 80 percent by the disc brakes and 20 percent by the tread brakes. The trailer coaches have a tare mass of 30.8 3-74 m etric tons (34 tons) and nom inal 5.4 m etric tons (6 tons) passenger payload. The catering vehicle in the form ation has a 38 tons tare m ass but has corresponding low er passenger p a y l o a d . Deceleration Rate T he characteristics o f the non-asbestos brake pads is such that they generate a uniform retardation force throughout the speed range. The cast iron tread brakes have a low high speed frictional characteristic rising to a higher value as the speed slow s. The low proportion o f the tread braking is such that it can be assum ed that the IC 125 has a uniform deceleration rate across the speed range. To obtain the Full Service stopping distance o f 1,770 m from 200 km /h requires an established deceleration rate o f 3.4 km/h/s (0.946 m/s2), having taken into account the brake propagation and actuator fill tim es. The Em ergency braking also results in a deceleration rate o f 3.4 km/h/s; how ever, the stopping distance is slightly reduced due to a faster brake propagation. The 1 0 2 5 requires 10 percent adhesion levels to sustain the Full Service retardation rates. - N orm ally, drivers are able to control the vehicle's speed w ith low er braking dem ands. Typically, stops from 200 km /h w ill be done in N otch 4, w hich is approxim ately 65 percent of Full Service. This is because the signaling distances are in excess of the m inim um value. Each vehicle in the 1 0 2 5 is designed to brake its ow n m ass/payload irrespective o f vehicle speed and braking duty. Thus theoretically there is no m inim um form ation. H ow ever, to be consistent w ith other standard rules, a m inim um form ation o f seven coaches has been adopted to allow 200 km /h operation. Shorter form ations or ones operating w ith a distributor isolated are lim ited to 10 m ph below line speed. A 160 km /h speed restriction is also im posed in the event o f loss o f a vehicle's air suspension. 3.5.6 Environmental Considerations D uring the w inter m onths the air in the brake system is treated w ith antifreeze. A lso, in periods of falling snow the m axim um speed is lim ited to 160 km /h. The driver is required to apply su fficient brake every 10 m inutes to register a slow ing o f the train to ensure that the calipers are not allow ed to freeze and to prevent a w ater film from the m elted snow from developing on the discs. Braking Effects on Other Systems The use of w heel-m ounted discs throughout the IC 125 m eans that the brake system has a m inim al effect on the drag experienced by the trainset. The use of w heel m ounted discs, how ever, requires the w heel w eb to be designed to accom m odate the discs through the use of a straight w eb and the inclusion o f attachm ent holes. T he use o f split ring discs on the coach 3-75 w heelsets necessitates the use of 24 bolt attachm ents to attach the discs to each w heel. O n the other hand, the annulus discs on the pow er car only use eight attachm ents per w heel. T he bolting attachm ents have to be such that they allow relative expansion o f the disc relative to the w heel w hile having sufficient load paths to transm it the braking torque. T he actual techniques used depend on the individual designs o f the disc m anufacturers. T he m ost serious m echanical effect on the w heelsets is the possibility o f m artensite generation in the w heel tread follow ing w heel slide activity. T his can lead to m echanical tread dam age w hich requires rem edial action. M odifications to the W SP system are being investigated to reduce the effect. The tread brake on the pow er car w ill have a conditioning effect on the tread not available on the coaches. T he IC 125 originally operated w ith brake pads w ith resin that em itted a strong pungent sm ell under hard braking. The air conditioning system w as fitted w ith air shutters w hich closed w hen braking to reduce intake into the vehicle. T he vehicles have now been converted to operate w ith pads having reduced sm ell. T h e disc brake design is such that there is little noise generated during braking. T he braking o f the IC 125 has no know n effects on the track and, as it is fully m echanically braked, there are no effects on electrical system s. 3.5.7 Inspection and Test Requirements Pre-Departure D uring the initial preparation o f the IC 125, the traincrew carry out a continuity test o f the brake system . W ith the driver’s brake controller in the leading operational cab in R unning, thereby charging the A B P to 5.1 bar, the guard w ill m ove the brake controller in the trailing cab into the em ergency position, thus venting the A B P . T he driver should register ah em ergency brake application on his cab gauges. T he guard/senior conductor w ill advise the driver o f any isolations o f the brake system on the coach es that w ill affect the train's operation. In Service W ith the exception o f operating during falling snow , there are no other in-service inspections or testing requirem ents. D uring falling snow , the driver is required to apply su fficient brake force every 10 m inutes to register a slow ing o f the train. Maintenance Testing M aintenance testing falls into tw o categories. First, functional tests are carried out every 50 days to check the basic operation o f the brake system together w ith a detailed annual leakage and functional test. Second, tests for fault diagnosis or checks follow ing equipm ent replacem ent are conducted. 3-76 The basic functional test checks the output from the brake control units and the corresponding operation of the distributors. O peration of the D SD and A W S system s are also checked. C hecks on the operation o f the W SP system are carried out using test equipm ent w hich can also be used to diagnose faults. Follow ing overhaul, a detailed perform ance check is carried out on the brake equipm ent including functional and leakage testing. M aintenance Requirem ents R outine. The m inim um interval betw een exam ination is four days. D uring this exam ination, the pad thickness is checked and any pads below the m inim um acceptable size renew ed. The acceptability is determ ined using slide-in gauges. The m inim um thickness has an allow ance to ensure that a pad ju st passing the acceptable thickness does not w ear into its backing plate during the next four days. Pad lives are typically 40 days on the pow er car and 80 days on the coaches. W hen changing the pads, the freedom of the caliper equipm ent is checked. The 50-day m aintenance exam ination also checks the correct operation o f the bogie brake equipm ent. A ll reservoirs fitted w ith m anual drain cocks are checked for the presence of condensate w hich is drained. A utom atic drain cocks are checked for correct operation. The brakes are su bjected to the functional test outlined earlier. O verhaul. T he overhaul of the brake system can be divided betw een that carried out on the bogies and that on the bodies. The pow er car and the M klH coach are subject to differing overhaul regim es. The bogies o f the pow er car are overhauled every tw o years. The brake discs currently last tw o overhaul periods before renew al. The caliper actuator and tread brake units are overhauled at each bogie overhaul. W ith the exception o f the reservoirs, the body m ounted brake equipm ent on the pow er car is overhauled every six years. R eservoirs are overhauled every 12 years. The MkTTT bogies are overhauled every 2-1/2 years. A s w ith the pow er bogies, the brake discs last tw o overhaul periods. The actuator calipers and bogie-m ounted W SP dum p valves are overhauled at every bogie overhaul. The body-m ounted equipm ent is overhauled every five years except the reservoirs, w hich are overhauled every 15 years. R ubber air hoses are generally renew ed w hen the bodies are overhauled w ith the notable exception o f the intervehicle hoses w hich are date stam ped on fitting and renew ed after five y e a r s . T he overhaul o f the com ponents is either carried out at the m ain w orks or by specialists (including original m anufacturers) contracted to undertake the w ork. 3-77 Special Staff or Skill Needs T he traincrew are trained on the operation o f the train system s and are given a rudim entary fault finding course. A ll IC 125 sets are fitted w ith cab radios so assistance can be obtained from central m aintenance controllers in the event o f difficulties. T he m aintenance staff also receive training on the specific system s on the trainsets. The m aintenance staff have received sufficient training to enable them to tackle both m echanical or electrical m aintenance on the trainsets. In the case o f fault finding, depot-based technical staff or specially trained m aintenance staff w ill be em ployed. T he depot-based fault finding w ill be such that faulty com ponents or sub-assem blies can be identified. These w ill be exchanged for overhauled units and the defective item sent for repair/overhaul. 3.6 BRITISH RAIL INTERCITY 225 3.6.1 Description of Trainset The Intercity 225 trainsets w ere procured betw een 1988 and 1990 to operate at speeds of up to 225 km/h (140 m ph) over the recently electrified East C oast M ain Line. The principle routes are: London-D oncaster-Leeds London-York-Edinburgh-G lasgow T he routes had previously used InterC ity 125 trainsets operating at speeds up to 201 km/h (125 m ph). The IC 225's operate in fixed form ations of a C lass 91 electric locom otive, 9 M kTV trailer coaches, and a M kTV D riving V an Trailer. There are 31 trainsets operating 26 daily diagram s. The trainsets are currently operating at a m axim um speed o f 201 km /h, due to signalling and operational constraints. T he IC 225 is required to stop from 201 km /h (125 m ph) in the sam e signalling distance required for the 1 0 2 5 trains. The IC 225 has a m axim um w orking speed of 225 km/h (140 m ph). Stopping from this speed requires an extra signal spacing. T his allow s the braking rate above 201 km/h to be reduced to 60 percent o f that below 201 km /h for the corresponding braking dem and. The vehicles are thus fitted w ith a speed controlled tw o-stage b r a k e . 3.6.2 Braking System Design The InterC ity 225 vehicles are fitted w ith a tw o-pipe A utom atic A ir Brake System . The C lass 91 locom otive equipm ent w as supplied by D avies and M etcalfe (D & M ). The M kIV coach equipm ent w as supplied by W estinghouse Brakes. 3-78 C lass 91 E lectric Locom otive The C lass 91 locom otive regulates the air brake pipe (A BP) by a version of the D & M E 70 brake control unit. T his is connected electrically to the driver’s brake controllers on the locom otive and via a Tim e D ivision M ultiplex (TD M ) system to a rem ote driving trailer, w hich is also fitted w ith an electrically controlled brake u n it The tw o bogies o f the locom otive have independent brake control system s. Each bogie has its ow n graduated apply and release “U IC ” style distributor connected to the A B P . Each distributor has a dedicated brake supply reservoir charged via a ch eck valve from the locom otive's nom inal 10 bar (145 psig) M ain Reservoir Supply (M R S). W hen w orking as a dead locom otive, the air supply can be obtained from the M ain R eservoir Pipe (M R P) charging the M R S to 7 bar (102 psig). In the event of no M R P supply, the brake supply reservoirs can be charged via the distributor from the A B P . T he brake control system provides the control o f the tw o rheostatic brake units, one per bogie. T he output signal from the distributor is fed into a rheostatic brake control unit. A dditionally, it feeds a brake dem and signal into a tw o-stage relay valve w ith hold o ff cham bers. The level o f rheostatic brake initiated by the rheostatic brake unit is m onitored 1 and converted into an air signal w hich is fed into the hold o ff cham ber o f the relay valve. T his ensures that the rheostatic brake is fully blended w ith the friction brake. The locom otive has tw o friction brake system s. First, disc brake units are fitted on each o f the four body-m ounted traction m otors, the calipers o f w hich are fitted w ith non-asbestos brake pads. Second, the bogies are fitted w ith air operated tread brake units using com position block' m aterials. T he tread brake units also incorporate a separate hydraulic apply-and-release parking brake actuator. The disc and tread brake system s operate in p a r a l l e l . In addition to the autom atic air brake system , the locom otive has a direct acting independent brake for use w hen buffering up to the train and for light locom otive m ovem ents. The locom otive is fitted w ith tw o start/stop com pressors charging the local M R S to a nom inal 10 bar. The train's M R P is charged via a pressure control valve to a nom inal 7 bar. The locom otive is fitted w ith a G E C w heel slide protection (W SP) system w hich operates on individual w heelsets. T he W SP w as originally linked to a doppler speed sensing system ; how ever, this feature has been isolated, relying solely on w heelset-generated speed signals. C lass 91 Electric Locom otive M ajor Com ponents A ir C om pressor and D elivery System s. The D & M tw o-stage com pressors are fitted to supply air via a check valve to the m ain reservoir supply. The com pressors operate under the control o f a m ain reservoir supply governor starting and stopping the com pressors to m aintain a nom inal 10 bar (145 psig) pressure. The system is protected by a safety valve set at 10.7 bar (155 psig). 3-79 The air is cooled externally and fed to the four m ain reservoirs w hich are m ounted one externally and three w ithin the body. C ondensate is rem oved by autom atic drain valves. The locom otive is not fitted w ith an air dryer. For w inter operation, antifreeze is introduced into the air system . B rake C ontrol U nit. The D & M E 70 brake unit controls the A B P pressure in seven steps using a three-w ire binary coded signal betw een the driver’s brake controller and the brake unit. The A ir Brake Pipe C ontrol signal is fed to a relay valve to charge/vent the A B P. The A B P can only be charged if the feed cut off valve is energized. T he E 70 unit generates the control signal using electronically controlled Electro-Pneum atic (E P ) valves m onitored by pressure transducers to produce the appropriate control signal corresponding to the brake dem anded by the train w ire signal. T he control unit obtains its air supply from the locom otive m ain reservoir supply. D istribu tors. The distributors are D & M “U IC ” style graduated apply-and-release units. The distributors incorporate the ability to charge their brake supply reservoirs from the A B P in the event o f no m ain reservoir supply. B rake R elay V alve. The R elay V alve has tw o m ain functions. First, to sw itch the output pressure betw een the tw o brake duty conditions above and below 201 km /h (125 m ph). Second, to hold o ff the friction brake proportional to the achieved rheostatic braking. A fully-rated rheostatic brake is fitted to the C lass 91. In general, the friction brake w ill only be blended in below 48 km/h (30 m ph), w here the rheostatic brake perform ance drops sharply w ith low er speed. Final stopping is perform ed by the friction brake. R heostatic B rake C ontrol U nit. The am ount of rheostatic brake required is derived from the distributor output pressure. T he control unit also reduces rheostatic duty above 201 km /h (125 m ph) to m atch the friction brake duty. T he control unit m onitors the perform ance o f the rheostatic brake and converts this into a pneum atic signal that is fed to the brake relay valve to hold o ff the equivalent friction brake. D isc B rake A ctuators/C aliper System . The brake actuators have integral slack adjusters to m aintain the required pad to disc clearance. A non-latching resetting m echanism is included to allow the renew al of brake pads. T he calipers, w hich are m ounted on the traction m otors, have pad holders fitted w ith 500 cm 2 pads utilizing the U IC style dovetail attachm ent. R etention o f the pads is by m eans o f a latch w hich is captive to the pad holder. T read B rake U nit. The tread brake unit is m ounted on the bogie acting independently on each w heelset. Each unit contains the service brake cylinder w hich is air applied and a hydraulic apply-and-release parking brake actuator. T he output force is taken through an integral slack adjuster to m aintain the required block/w heel clearance. T he block holder is fitted w ith a pair o f com posite m aterial brake blocks. M kIV Trailer Coach The M kIV vehicle has a single “U IC ” style graduated apply and release distributor w hich is connected to the A BP. T he distributor has a dedicated auxiliary reservoir w hich can be 3-80 charged via the distributor from the A B P. N orm ally, the M R P w ill charge the auxiliary reservoir at 7 bar via a check valve thus form ing the tw o pipe system . T he distributor supplies an air pressure signal to a tw o-stage variable load relay valve. The air pressure in the brake actuator can be varied depending on braking dem and, load in the vehicles, and w hether the speed is above or below 201 km /h. The M kTV vehicles are fitted w ith B T 41 air suspension bogies. A n output o f the air suspension pressure is fed into the variable load Telay valve. T he output pressure from the relay valve is fed to the brake actuators w hich are fitted to the bogie-m ounted brake calipers. These apply non-asbestos brake pads to three axle-m ounted brake discs w hich are fitted to each w heelset. The M kTV vehicles are fitted w ith a Faiveley W heel Slide Protection (W SP) system w hich operates on a local vehicle basis acting on individual w heelsets. M klV Trailer Coach M ajor Com ponents B rak e M odule. A ll the equipm ent associated w ith the braking system and the air suspension is fitted w ithin a detachable brake m odule. D istribu tor. The distributor has the characteristics o f a “U IC ” style graduated apply and release unit. V ariable L oad R elay V alve. The output pressure from the distributor is fed into the tw o- stage relay valve w hich has a variable position fulcrum . The output pressure from the air suspension averaging valve sets the fulcrum position; thus, the pressure to the brake actuator is proportional to the vehicle's load. A “no load” signal causes the variable load relay valve to operate in the tare condition. The changeover betw een the tw o-stage braking duties is carried out independently on each coach. The control signal is generated from the W SP s y s t e m . B rak e A ctuators/C aliper System . The brake actuators have an integral slack adjuster to m aintain the required pad-to-disc clearance. A non-latching resetting m echanism is included to allow the renew al o f brake pads. T he caliper pad holders are fitted w ith 500cm 2 pads utilizing the “U IC ” style dovetail attachm ent R etention of the pads is by m eans of a latch w hich itself is captive to the pad holder. D isc B rakes. Three low -drag cast iron discs are fitted to each w heelset. The grade o f cast iron used depends on the disc m anufacturer. The discs and caliper system s have been obtained from SA B W A BC O and Knorr Brem se. M klV D riving V an Trailer The M kTV D riving V an Trailer (D V T) regulates the A BP by a W estinghouse D W 3 brake control u n it This is connected electrically to the driver’s brake controllers and via a TD M system to the locom otive at the other end o f the train form ation. 3-81 The friction brake system is basically the sam e as that fitted to the M kIV coach, w ith the principal exception being that each bogie has its ow n tw o-stage relay valve due to differing bogie loads. O ne brake actuator of each w heelset also incorporates a hydraulic apply-and-release parking brake actuator. M kIV Driving Van Trailer M ajor Com ponents The M kTV trailer coach com ponents described above are also fitted to the driving van trailer. V ariable Load R elay V alves. The difference in pivot loads betw een the tw o bogies necessitates the fitting o f tw o variable load relay valves, one per bogie. A single distributor feeds the brake dem and signal to both units. B rak e A ctuators. O ne actuator per w heelset is fitted w ith a hydraulic apply-and-release parking brake actuator. B rake C ontrol U nit. The D V T is fitted w ith the W estinghouse D W 3 brake control unit. The role of the unit is the sam e as the E 70 unit fitted to the C lass 91 locom otive. The D W 3 unit generates the brake pipe control signal by using the brake control w ire to sw itch pressure signals into a m ulti-diaphragm unit w hich uses the different diam eters o f the enclosed cham bers to produce the appropriate pneum atic control signal. The D W 3 unit obtains its air supply from the M ain R eservoir Pipe. 3.6.3 System O peration and C ontrol T he principal operation o f the air brake system is such that, after an initial reduction o f pressure in the A B P sufficient to trigger the distributor, the am ount o f brake application is proportional to the reduction in the A B P pressure. The brake is released by recharging the A BP pressure. A reduction of 1.5 (17.4 psig) bar in the A B P pressure is required to produce a Full Service brake application. In an em ergency brake application, the A B P falls to zero. The reduction or increase in A B P pressure is achieved by m eans of the brake control units at both ends of the trainset responding to the electrical signals derived from the driver’s brake controller in the operational cab. A reduction in the A B P pressure can also be achieved by the safety system s fitted to the trainsets. T he driver’s brake controller has eight positions, w hich are R unning, 1 through 6, and Em ergency. The brakes are fully released, provided none of the safety system s have operated, w hen the driver’s brake controller in the operational cab is in the R unning position. This energizes the three brake control w ires at each end of the train via the TD M system allow ing the A B P to be charged to the Running pressure o f 5.0 bar (72.5 psig). M oving the driver’s brake controller through the other positions causes the control w ires to be sw itched in a binary code sequence such that w hen in the Em ergency position all the control w ires are de-energized. 3-82 T he tw o brake control units, one at each end o f the trainset, respond to the status o f the control w ires resulting in even braking steps being achieved betw een Initial (Step 1) and Full Service (Step 6). W hile both brake control units are capable of venting the A B P to achieve the required brake step, the rear unit is prevented from recharging the A B P by a de-energized feed cu t-off valve. T he A B P is thus vented from both ends of the IC 225 in response to the driver’s brake dem and, but can only be recharged from the leading vehicle. There is no direct connection betw een the brake control signals and the vehicles’ distributors. T he distributors respond solely to variations in the A B P pressure. T he characteristic o f the distributors is such that the driver can continually vary the am ount o f brake dem and throughout the brake application. T he tw o-stage brake relay valves fitted to all the IC 225 vehicles change over betw een the tw o brake duties at approxim ately 201 km/h. Each vehicle changes over independently. W hen operating above 201 km /h, a speed signal derived from the W SP system energizes an EP valve causing the relay valves to adopt the low er braking rate. Since the IC 225's are currently lim ited operationally to 201 km /h, the relay valves rem ain in the higher braking rate c o n d i t i o n . T he C lass 91 locom otives rheostatic brake responds to distributor output pressure via th eJ rheostatic brake unit, w hich also converts the achieved braking rate into a signal to back off the friction brake by feeding it into the hold o ff cham bers o f the relay valve. This arrangem ent m eans that the rheostatic brake is used in preference to the friction brake. The use o f the locom otive's batteries to establish the field currents in the m otors during rheostatic braking m eans that the rheostatic brake can rem ain operational in the absence o f an overhead line supply. R heostatic braking is available in all braking steps including Em ergency. Service and Override Capability ® T he braking control system uses electrically controlled brake units located in the C lass 91 and M kIV D V T at each end of the IC 225 to control the pressure in the A ir Brake Pipe. The brake control units respond to a binary code signal on three brake control lines generated by the driver’s brake controller in the leading operational cab. A ll lines need to be energized to release the brakes. The lines are progressively sw itched. W hen they reach N otch 7 (Em ergency), they are all de-energized. The brake control lines at the rear of the IC 225 are energized via a TD M com m unication system copying the status o f the control lines in the leading vehicle. L oss o f T D M configuration w ill cause the rear brake control lines to be de-energized, thus applying the b r a k e . T he distributors and hence the relay valves respond directly to the A B P pressure controlled by the brake units. A pplication/increase in brake force is initiated from both brake control units reducing the A B P pressure. Reduction/release of the brake force is only achieved by the brake unit in the leading vehicle recharging A B P pressure. 3-83 T he control system design is such that once any o f the safety system s fitted to the train are triggered, the driver cannot override its application. T he only exception is that the driver can hold o ff a passenger-initiated brake application w hen the passenger com m unication system is o p e r a t e d . Diagnostic Systems The IC 225 is fitted w ith no diagnostics and only lim ited m onitoring system s. T he driver is presented w ith system pressure gauges derived from tappings on the vehicle. The driver gets an indication o f W SP activity on the leading vehicle. The coaches have a latched relay to indicate if W SP lockout has occurred. This is prim arily to advise the m aintenance staff o f its operation. U nder fault conditions, the driver can isolate individual system s on the IC 225 w ith the train proceeding forw ard at reduced speed or at line speed depending on w hich system /com ponent has been isolated. 3.6.4 Safety Features Class 91 Locomotive and M k l V D V T The C lass 91 locom otive and the M klV D V T are fitted w ith the follow ing safety features: ( i ) D rive r’s Safety D evices (D S D ), V igilance System and Speed S w itch W hile the m aster controller is in either Forw ard or R everse, the driver m ust retain pressure on a foot pedal. O nce every 60 seconds, how ever, the driver has to release and then reapply pressure to the foot pedal to prevent the A B P from being vented. T o prevent uncontrolled coasting w ith the m aster sw itch at O ff or N eutral, a speed sw itch w ill apply the brakes if travelling over 5 km /h (3 m ph). ( i i ) A utom atic W arning System (AW S) T he A W S m onitors the condition o f the lineside signals. If green, the driver w ill hear a bell. H ow ever, on passing a signal not show ing green, the driver w ill hear a horn. Failure to cancel the hom w ithin three seconds w ill result in the A B P being vented, thus applying the train brakes. T o enable the 225 km /h capability of the IC 225 to be used, B ritish R ail is currently evaluating A utom atic Train Protection System s. These w ill m onitor not only the lineside signals, but also the driver's control o f the train and w ill autom atically apply the brake if the train speed is outside set lim its. U ntil fitted, the IC 225 w ill be lim ited to 201 km /h. 3-84 ( i i i ) Low M ain R eservoir P ipe Pressure T he pressure in the M R P is continually m onitored to ensure that there is su fficien t energy available to stop the train. ( i v ) B rake C ontrol U nit C harging C apacity T h e rate at w hich the brake control units can recharge the A B P is restricted such that it is insufficient to overcom e the loss o f air from the A B P w hen one o f the safety system s is activated. ( v ) D rive r’s B rake C ontroller Em ergency P osition In addition to the train brake control w ires being de-energized, the Em ergency position causes the A B P to be vented directly. This feature is also available from all non-operational cabs. ( v i ) D rive r’s Em ergency P lunger T h e cab is fitted w ith a plunger that also causes the A B P to be vented directly. O nce operated, it rem ains in a latched position until reset. ( v i i ) H yd ra ulic P arking B rake Interlock T h e interlock ensures that should the indicators, built w ithin the parking brake control units, not be in the “O ff’ position, the A B P w ill be vented. M k I V Trailer Coaches ? T he M kTV trailer coach ’s braking system is fitted w ith the follow ing safety features: ( i ) P assenger C om m unication System O peration o f any of the passenger alarm handles, including releasing the em ergency w indow ham m ers, vents a pilot line. This in turn causes the A B P to be vented by a pilot-controlled exhaust valve. T he driver is advised electrically that the passenger com m unication system has been activated. The driver can override the venting o f the A B P caused by the Passenger Com m unication System . ( i i ) E m ergency D o or Release Interlock T he M kTV vehicles are fitted w ith pow er-operated external doors. If a passenger operates the door release, this w ill vent a pilot-controlled exhaust valve venting the A B P. The driver is unable to override this brake application. 3-85 ( i i i ) A ir Suspension C harging V alve The air suspension system derives air from the M R P w hich is prim arily for the brake system . The charging valve prevents the air suspension being charged before the vehicle's auxiliary reservoir has been charged in excess o f five bar. Additional Safety Features T he IC 225 form ation incorporates the follow ing additional safety features: ( i ) T rain C ontinuity Train continuity is continually m onitored by the brake system . Should the train divide, the A B P inter-vehicle couplings w ill part, venting the A B P in both parts o f the train, thus applying the brake. ( i i ) T D M S y s t e m T he condition o f the TD M system is m onitored by the rear control unit w hich w ill apply the brake in the event o f a loss of the “R unning” signal. ( i i i ) P arking Brakes Electric operation o f the parking brakes on either the C lass 91 or the M kTV D V T w ill cause the parking brake to be applied or released on both units. L ocal m anual application and release facilities are fitted to both veh icles. 3.6.5 Technical Specifications of the Braking System Speed Range T he technical specification for the braking system w as set by the requirem ent for the IC 225 to stop from 2G1 km /h in the sam e signalling distance required for the IC 125 trains. This signalling distance w as originally set for 161 km /h (100 m ph) operation w ith locom otive- hauled tread brake trains. T he m inim um signalling distance to allow 201 km /h running is thus 2,040 m eters betw een the first caution signal (double yellow ) and the red signal. The signalling distance generally is greater than the m inim um and w as usually set w hen the signalling system w as introduced. The m inim um perform ance requirem ent is that the IC 225 shall be capable o f stopping from 201 km /h in 1,770 m eters. The safety m argin is to allow for speedom eter error and adverse rail conditions. The IC 225 has a m axim um w orking speed of 225 km/h. Stopping from this speed requires an extra signal spacing to be added to that for 201 km /h. Thus for 225 km /h running, the signalling distance has been increased to 3,060 m eters. Sections o f the East C oast M ain Line 3-86 have had the signalling system m odified to give an extra signalling aspect (flashing green) to perm it 225 km /h running. H ow ever, running at 225 km /h is suspended, pending the introduction o f an A utom atic Train Protection (A TP) system onto this route. W h e e l Slide Protection The G EC W SP and Faiveley W SP fitted to the C lass 91 and M kIV s, respectively, utilize digital electronics to determ ine if the w heelset is sliding or rapidly slow ing. E ach w heelset sends a speed signal into the control unit w hich com pares the individual speeds and their rates o f deceleration against the unit's internal perform ance characteristics. A dum p valve releases the brakes on the appropriate w heelset w henever the W SP unit identifies the w heelset rapidly slow ing or sliding. T he dum p valve has a blending action capable o f progressively exhausting and filling the brake actuators as the W SP system attem pts to m atch the available a d h e s i o n . If the dum p valve has been venting the air continuously for 10 seconds, the W SP unit assum es a fault and progressively re-establishes fu ll braking and locks out the dum p valve for the rest o f the stop or until all four w heelsets are operating w ithin 6 m ph (10 km /h) o f each o t h e r . Retarding Force Each vehicle in the IC 225 w as originally required to brake its ow n proportion o f the train's m ass. The C lass 91 locom otive achieves this requirem ent w hen operating w ith its blended rheostatic brake. In the event o f rheostatic brake failure/isolation, the friction brake only establishes 80 percent o f the retarding force required to brake the 84 ton locom otive independently. The M kIV trailer coaches have a tare m ass of 40 tons and a nom inal six ton passenger payload. The catering vehicle in the form ation has a 46 ton tare m ass but has a low er passenger payload. The D V T also has a 46 ton tare load split asym m etrically betw een the bogies. C urrent B ritish R ail policy states that passengers are not allow ed in the leading vehicle w hen the train is operating above 161 km /h. T he van area is used for parcels and m ail traffic. The perform ance of the M kIV vehicles exceeds the m inim um requirem ent such that if IC 225 w ere to operate w ith the C lass 91 locom otive's rheostatic brake isolated, there is sufficient retarding force in the train to stop w ithin the 1,770 m eters m inim um perform ance requirem ent Deceleration Rate The characteristics o f the non-asbestos brake pads and the com posite brake blocks used on the IC 225 vehicles are such that they generate a uniform retarding force throughout the speed r a n g e . 3-87 T o obtain the Full Service stopping distance o f 1,770 m eters from 201 km /h requires an established deceleration rate o f 3.4 km /h/sec (0.946 m/s2), having taken into account the brake propagation and actuator fill tim es. T he Em ergency brake rate requirem ent is also 0.946 m/s2. T he characteristics o f the brake pads and the use o f three discs per w heelset originally designed to dissipate the energy for a 225 km /h stop has m eant that the M kTV coaches can achieve a deceleration rate o f better than 3.9 km/h/s (1.1 m/s2) from 201 km /h. T he fully rated rheostatic brake m eans that the C lass 91 w ill norm ally achieve the required 0.946 m/s2 deceleration rate. The overall perform ance of the IC 225 is in excess o f this value due to the effect of the M kIV vehicles. The norm al IC 225 form ation is capable of com pensating for a C lass 91 locom otive operating w ith both its rheostatic brake units isolated. T he IC 225 requires 12 percent adhesion levels to sustain the Full Service retardation rates o f the M kIV vehicles. N orm ally, drivers are able to control the vehicle's speed w ith low er braking dem ands. Typically, stops from 201 km /h w ill be done in N otch 4, w hich is approxim ately 65 percent o f Full Service. This is because the signalling distances are generally in excess of the m inim um value. 3.6.6 Environmental Considerations Environmental Considerations D uring the w inter m onths the air in the brake system is treated w ith antifreeze. A lso, in periods of falling snow , the m axim um speed is lim ited to 161 km/h (100 m ph). The driver is required to apply sufficient brake every 10 m inutes to register a slow ing o f the train to ensure that the calipers are not allow ed to freeze and to prevent a w ater film from the m elted snow from developing on the discs. Vehicle Configuration The norm al form ation of an IC 225 is a C lass 91, 9 M kIV coaches and a M kIV D V T. The m inim um form ation that still allow s 201 km /h running, even w ith a class 91 w orking w ithout an operational rheostatic brake, is C lass 91, 6 M kTV and a M kTV D V T. Shorter form ations or ones operating w ith a distributor isolated are lim ited to 16 km /h (10 m ph) below line speed. A 161 km /h speed restriction is also im posed in the event o f loss of vehicle air suspension. Braking Effects on Other Systems T he C lass 91 locom otive w as originally designed to be capable o f braking its ow n w eight w ith or w ithout rheostatic brake assistance. Therm al m odelling o f the w heel show ed that under m echanical braking alone the w heel/hub interference could be com prom ised. C onsequently, half the tread brake duty has been rem oved leaving the C lass 91 locom otives 80 percent braked w hen operating w ith both the rheostatic brakes isolated. 3-88 The m axim um braking duty o f the rheostatic brake on the C lass 91 is w ithin the continuous rated duty o f the traction m otors. T he field currents for the m otors are derived from the vehicle batteries so the use o f rheostatic brake is independent o f an overhead train supply. The M kTV coaches are fitted w ith low drag discs to m inim ize the effects on train resistance w hen not braking. T he internal connections betw een the braking faces are arranged in pillars. This pattern ensures good therm al conductivity w ith m inim al pum ping losses. The drag of the d iscs is typically h alf that o f radially cooled discs. The vehicles operate w ith non-asbestos pads and blocks that have a low sm ell and noise em ission during braking. There are no know n effects of the brakes on the track. 3.6.7 Inspection and Test Requirements Pre-Departure D uring the initial preparation o f the IC 225, the driver w ill carry out a continuity test o f the brake system . W ith the driver’s brake controller in the operational cab in R unning, thereby charging the A B P to 5.0 bar (72.5 psig), the driver w ill operate the brake test sw itch. This has die effect o f tem porarily stopping the leading brake control unit from charging the A B P and initiating an em ergency brake application on the rear brake control unit. T he driver should register an em ergency brake application on his cab gauges. The guard/senior conductor w ill advise the driver o f any isolations o f the brake system on the coach es that w ill affect the train's operation. In Service W ith the exception o f operating during falling snow , there are no other in-service inspections or testing requirem ents. D uring falling snow , the driver is required to apply su fficient brake force every 10 m inutes to register a slow ing of the train. Maintenance Testing M aintenance testing falls into tw o categories. First, functional tests are carried out every 12 w eeks to check the basic operation of the brake system . T he basic functional test checks the output from the brake control units and the corresponding operation o f the distributors. O peration o f the D SD and A W S system s are also checked. C hecks on the operation o f the W SP and rheostatic brake system s are carried out using autom ated test equipm ent, w hich can also be used to diagnose faults. Follow ing overhaul, a detailed perform ance check is carried out on the brake equipm ent including functional and leakage testing. 3-89 M aintenance Requirem ents R outine. The m inim um interval betw een exam ination is seven days. D uring this exam ination the pad thickness is checked and any pads below the m inim um acceptable size renew ed. The m inim um thickness has an allow ance to ensure that a pad ju st passing the acceptable thickness does not w ear into its backing plate during the next seven days. Pad lives are typically in excess o f 750 days. The C lass 91 pad and block life is dependent on the num ber o f days operating w ith the rheostatic brake isolated. W hen changing the pads, the freedom o f the caliper equipm ent is checked. T he operation of the caliper equipm ent is checked during a six-w eek exam ination, and also form s part o f the 12-w eek functional checks. A ll reservoirs w ith m anual drain cocks are checked as part o f the six-w eek exam ination. O verhaul. The IC 225 w as procured w ith a six-year overhaul interval. Currently, the C lass 91 locom otives receive an extensive exam ination/light overhaul at three years. T h e actuators and tread brake units receive a perform ance check and light repair at three years and are fully overhauled at six years. T he other brake equipm ent is overhauled at six years w ith the exception o f the stainless steel reservoirs w hich w ill be overhauled at 12-year i n t e r v a l s . T he overhaul o f the com ponents is either carried out at the m ain w orks or by specialists (including original m anufacturers) contracted to undertake the w ork. Sp ecial Staff or Skill N eeds T he traincrew are trained on the operation o f the train system s and are given a rudim entary fault finding course. A ll IC 225 sets are fitted w ith cab radios so assistance can be obtained from central m aintenance controllers in the event o f difficulties. T he m aintenance staff also receive training on the specific system s on the trainsets. The m aintenance staff have received sufficient training to enable them to tackle both m echanical or electrical m aintenance on the trainsets. In the case o f fault finding, depot-based technical staff or specially trained m aintenance staff w ill be em ployed. T h e depot-based fault finding w ill be such that faulty com ponents or sub-assem blies can be identified. These w ill be exchanged for overhauled units and the defective item sent for repair/overhaul. 3-90 S c A2 A2 C A2 A2 B2 Y 1 FS N Y 1 N N N N N N FT N N N Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Braking effort is too high resulting in resulting of high too level is Reduce effort decrease. Braking speed rapid braking of level increase Must HowDetected/Response braking requested. braking Train does not slow quickly enough. quickly slow not does Train Must down. slow in not does resulting Train high too is effort Braking braking of level increase Must requested, possibly even emergency even possibly requested, braking requested. braking utilize emergency brake. emergency of utilize level Reduce decrease. speed enough. rapid quickly slow not does Train Must down. slow not does Train enough. quickly braking slow of not emergency does via level Train possibly increase Must requested, requested. braking. utilize emergency brake. emergency utilize brakes. Braking effort is too low, increasing low, too is effort distance. Braking stopping all. at occur not does Braking Effect on Overall Braking System Braking Overall on Effect Rapid decrease in speed beyond speed in decrease Rapid desired. level increasing low, too is trainset. for effort distance Braking stopping resulting low too is braking Friction Rapid decrease in speed beyond speed in decrease Rapid desired. level all. at occur not does Braking in increased stopping distances. stopping increased in fable 3-12. Intercity 225 F225 M Intercity fable3-12. E AWorksheet should given the actual rheostatic actual the given should Braking does not occur at all. at occur not does Braking desired above occurs Braking level. desired under is Braking all. at occur not does Braking Effect on Braking Subsystem Braking on Effect desired above occurs for Braking level desired under is Braking Two stage relay valve holds off holds valve relay stage Two level for trainset. for level the trainset. the level for the trainset. the for level more friction braking than it than braking friction more level. braking Fails indicating Fails No signal for signal No much too for Signal little too for Signal Failure Mode Failure much too for Signal little too for Signal rheostatic braking rheostatic effort. braking when braking requested. braking braking braking. for signal No requested. braking braking braking. higher than actual than higher braking when braking Intercity 225 (Great Britain) Britain) (Great 225 Intercity 11 of 1 Page Unit BCU) Unit Component (electrically signals (electrically Control Unit Control Brake Control Brake (Includes Unit2 valves, pressure electropneumatic relay valves, transducers, DVT. Driver’s Brake Driver’s BCU One valve) Controller Rheostatic Brake Rheostatic per locomotive or locomotive per the Brake Control Brake the 3 - 9 1 D S A3 B3 B3 B3 FS Y N N N N Y f t Y N Y Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT- = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT- Braking effort is too high resulting in resulting high too is HowDetected/Rcsponse effort Braking Assume driver can isolate system and system isolate can driver Assume rapid speed decrease. Reduce level of level Reduce decrease. speed rapid continue at reduced speed or line speed line or speed reduced at continue braking requested. braking Wheelslide indicated to driver. to indicated Wheelslide failure. of degree on depending of indication 10 receives within operator are Assume wheelsets all that so lower braking effort than requested. than applied effort brakes and braking out lower locked WSPis will be too low. Driver can try to effort try can braking Driver km/hr low. 201 < V too Once be will brakes. emergency increase braking level, possibly via possibly level, braking increase too high resulting in excessive wear on wear excessive and in Inspection resulting high brakes. too friction When V > 201 km/hr, braking rate is rate braking km/hr, 201 > V When km/hr of each other. each of km/hr maintenance indicates wear. indicates maintenance Effect on Overall Braking System Braking than Overall higher on is Effect braking Friction required. Wheelset Slip Protection Slip Wheelset required. 10 seconds results in WSPlockout, in results seconds 10 wheelset causing wheel slide for the for slide wheel causing wheelset may be overworked as a result. a as overworked be may Over application of brakes on one on brakes of application Over below is wheelset to applied Braking wheelset. desired braking level resulting in resulting the level failed for the braking braking with no desired or associated reduced wheelset control. Continuous venting beyond venting until of Continuous km/hr application 10 control. brake within are gradual then if wheelsets truck all other. the each for O.K. is 201 V< duty once but Braking km/hr, V>201 km/hr, braking duty will be too low too be will duty braking truck. km/hr, the for Braking duty is O.K. for the track if track the for O.K. is duty Braking track. the for V< 201 km/hr, but if V > 201 > V if but km/hr, 201 V< km/hr, braking duty will be too high too be will duty braking km/hr, Table 3-12. Intercity 225 F225 M Intercity Table3-12. E A(cont.) Effect on Braking Subsystem Braking on Effect applied for the actual rheostatic actual the for applied wheelset to applied Braking slip. Two stage relay valve does not does valve relay stage Two friction for overheating and/or given the actual lheostatic actual the given is above desired braking level This braking slip. desired wheel above in is resulting brake level, not alleviating wheel alleviating not level, brake much friction braking being braking wear friction much Excessive level. braking is wheelset to applied Braking braking level. This results in too in results This level. braking hold off enough friction braking friction enough off hold causes excessive wear on wheels on wear excessive causes rails. and Results in maintaining current maintaining in Results brake components. brake braking level no or braking reduced in desired below resulting in WSP lockout, then gradual then WSPlockout, in Braking duty is O.K. for the tiuck the for O.K. is duty Braking for the wheelset associated with associated wheelset the for the failed control. Continuous control. failed the venting beyond 10 seconds results seconds 10 beyond venting brake application until all until application brake wheelsets are within 10 km/hr of km/hr 10 within are wheelsets other. each km/hr, braking duty will be too be will duty braking truck. the km/hr, for low if V>201 km/hr, but once V< 201 V< once but km/hr, V>201 if truck the for O.K. is duty Braking if V< 201 km/hr, but if V > 201 > V too if be but will km/hr, duty 201 V< if braking km/hr, high for the track. the for high Failure Mode Failure indicating Fails lower than actual braking than lower rheostatic effort. Fails with output with modulate to Fails cylinder failing brake the output with to brake Fails pressure requesting cylinder open. Fails to high speed high to Fails pressure. thus vented, be keeping the valve the keeping level. speed low to Fails level. Component Intercity 225 (Great Britain) Britain) (Great 225 Intercity 11 of 2 Page speed sensor) speed Rheostatic Brake Rheostatic Unit Control Operates on Operates braking speed Control (includes Control Protection3, WSP, Protection3, wheelsets Valve (high or low Relay or Stage Two (high Valve Wheelset Slip Wheelset individual level) 3 - 9 2 S D D D A2 D C FS Y Y N Y Y Y 1 f t Y Y Y N Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT HowDetected/Response battery on indicators has driver Assume status. Repair at first maintenance first at Repair status. opportunity. catenary and battery status. Battery status. battery and catenary speed. Assume driver has indicators on indicators if has operate driver to Assume brake allows power friction more allowing by braking needed. braking. line or speed lower and continue and cab indicate low pressure. low indicate cab Speed reduction. Pressure gauges in gauges Pressure reduction. Speed Relay valve reacts to lower rheostatic lower to reacts valve Relay of wheelset the Failure isolate driver. by can WSPmonitored driver motor, rheostatic lower to friction reacts more valve allowing Relay by braking braking. rheostatic braking is still available. still is braking rheostatic be to system. effort braking the requested for slide wheel Unintentional All brakes applied to degree of low of degree to applied brakes All Effect on Overall Braking System Braking Overall on Effect and power supplies Battery for brake is backup no rheostatic except the for effect, No available braking. friction slide. wheel be alleviate to effort braking braking. requested friction the track with the failed battery failed the of with all track or more the allow will valve Relay to WSPattempts of track. all motor or more allow will valve Relay pressure failure. pressure Table 3-12. Intercity 225 F225 M Intercity Table3-12. E A(cont.) available for the rheostatic brake is backup no rheostatic except the for effect, No available rheostatic in track. decrease motor or the of Loss for the braking for slide wheel Unintentional Effect on Braking Subsystem Braking on Effect Loss of or decrease in rheostatic in decrease or of Loss applied. brakes Friction for the track with the failed the with track the system. for battery slide. wheel alleviate track. motor the for braking Battery back up power initiates. power up back Battery motor track. WSP attempts to WSPattempts track. motor Inability to dissipate to Inability energy/heat brake entire (Effects system) Loss of battery of Loss produce dissipate not to Does resistor in current current axle grids. failure, Bearing seizes. Fails with Low with Fails power or decrease in decrease or power power. battery Failure Mode Failure decrease in power. in decrease Pressure Loss of power or power of Loss Motor Truck5 Motor Pipe Brake Air (ABP) Batteiy (Assume a (Assume Batteiy available for each for available Resistor Grids Resistor Traction Motor (2 Motor Traction Intercity 225 (Great Britain) Britain) (Great 225 Intercity Component is system battery truck) 11 of 3 Page friction Braking friction per truck) per Motor Truck Motor Power Catenary fiiieuiitiitfc Braking* fiiieuiitiitfc 3 - 9 3 S A3 B3 B2 C A3 B3 N FS N N Y N N N Y FT Y N N Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT How Detected/Response How Braking effort is too high resulting in If resulting high possible, too If requested. is braking decrease. effort of speed level Braking rapid reduce emergency brakes if failure is extreme. is utilizing of failure if Possibility brakes enough. emergency Truck does not brake sufficiently. brake increased not be does must Truck effort Must Braking quickly. too slows Locomotive WSP is locked out and distributor and out speed. locked speed. is line WSP reduced at reduced Continue failure. of degree on depending speed isolated, operator can continue at continue can operator isolated, track’s brake and continuing at a at continuing and brake speed. track’s reduced because the train does not slow quickly slow not does for this of train the requested isolation because braking via of level possibly truck, decrease the requested. than effort braking Lower requested. Driver could isolate system line or isolate speed could reduced Driver at continue requested. and May have to operate at reduced speed reduced at operate to have May Potentially, speed reduction when not when reduction speed of degree Potentially, on depending speed line or failure. Truck with failed distributor brakes System Braking distributor Overall on the failed for Effect with low Truck too is effort Braking too much, overworks WSP for the for WSP occur may overworks lockout much, WSP too truck. Potentially lower braking level than level braking lower be may Potentially braking is applied friction Unneeded constantly effort Brake desired for the locomotive. Friction a low, failure locomotive. this in this the truck. is for only so regime mph desired 30 speed locomotive. below the small for applied possibly isolating the distributor. the isolating possibly 3 braking from lost effort equivalent to are applied, not these equivalent axle, effort 1 or Brake capability discs equivalent to effort from 3 discs or 1 or discs braking 3 in from discs, on effort equivalent wear to are these Excessive equivalent axle, effort. braking is only blended at speeds at blended only is braking problem. possible. wheels even and calipers, in braking effort. braking in Table 3-12. InterCity 225 F225 M InterCity Table3-12. E A(cont.) Braking is under desired level for level desired under is Braking Effect oh Braking Subsystem desired Braking above oh occurs Effect Braking wheelslide. Excessive wear Excessive wheelslide. should compensate to avoid to compensate slip. should wheel the truck affected including no including affected truck the is applied constantly effort Brake If current level of rheostatic of level current applied be If may braking Friction level for the truck. Wheelslide truck. the for level protection (WSP) prevents (WSP) protection and/or overheating on brake on overheating possible. and/or components braking is needed, not enough not needed, is control locomotive. slip braking the wheel for The required. braking is sufficient, there is no is there applied be sufficient, not will is is it braking braking when discs friction 3 locomotive from the for effort to lost applied, equivalent not effort Brake braking. iri equivalent ■ of are these overheating axle, or 1 or brakes on effort. effort from 3 discs or 1 axle, 1 or discs 3 from effort problem. If it is not and friction and not is it If problem. braking effort. Excessive wear Excessive effort. braking in braking equivalent are these brakes. braking capability equivalent to equivalent capability braking or no braking, fails braking, no or on brakes discs Fail Indicates higher than higher Indicates Failure Mode braking level, for Failure desired open. Signal above fails actual rheostatic actual closed. off brakes disc Fail Signal for too little too for Signal than lower Signals actual rheostatic actual braking braking. Disc Brake per one Disc Actuators (Assume Intercity 225 (Great Britain) Britain) (Great 225 Intercity Component Distributor 11 of 4 Page Valve (Blending of (Blending Valve axle) Two Stage Relay and brakes) Stage Two friction rheostatic 3 - 9 4 S A3 B3 A3 B3 D C N N N FS N Y Y N Y FT Y N Y N S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; =Y Safe; Fail = FS Tolerant; Fault =FT and continue at reduced speed or line or failure. speed of reduced degree at on continue depending and speed or line speed depending on degree of degree on depending speed line or May have to operate at reduced speed reduced at operate to have speed May reduced at operate to have May Potentially, speed reduction when not when reduction speed requested. Detected/Response than How Potentially, line effort or braking failure. speed of Lower requested. reduced degree at than on effort continue depending and speed braking Lower requested. Driver could isolate system isolate could Driver system requested. isolate could Driver requested. or line speed depending on degree of degree failure. on depending speed line or Gauges in cab indicate high pressure. high indicate cab in Gauges Potentially, speed reduction when not when reduction speed Potentially, of overpressure. of also. cab senses can in indicator pressure indicator and valve has low If has cab operation in Safety driver driver indicate Assume compressors. cab Assume compressor operation the in of Gauges one compressor reservoir. of brakes. operate emergency failure. necessary, assume operator must apply must operator assume necessary, Brake effort constantly applied is System disc. applied one Braking from braking from Overall constantly lost on effort effort to to Effect effort to applied, Brake not applied equivalent equivalent one effort brake on Brake lost constantly disc. capability effort one to effort applied, wheelset. Brake not one equivalent effort Brake capability enough has compressor second None. Safety valve on main on if valve or, wheelset. second of Safety brakes the duty None. as the friction over effect no no takes Either capacity, compressor reservoir acts to vent the reservoir to reservoir the vent to acts reservoir the correct pressure. correct the compressor. failed the Table 3-12. Intercity 225 F225 M Intercity Table3-12. E A(cont.) Brake effort constantly applied is applied Subsystem Braking constantly on Effect effort Brake system operating. system May not be able to energize, to able able be be may not May compressor second Brake effort constantly applied to on applied wear constantly lost Excessive effort applied, wheelset. Brake not one effort Brake Brake effort not applied, lost applied, not effort Brake equivalent to effort from one disc. one from effort to brakes. of equivalent overheating Excessive wear on brakes or brakes on wear Excessive required pressure to keep the keep to pressure required the friction brakes are brakes friction the brake capability equivalent to equivalent wheelset. one capability on brake effort brakes or overheating of brakes. of overheating or brakes beyond continues and reservoir braking capability equivalent to equivalent disc. one capability from braking effort to provide enough air at the at air enough provide to brake system. The result is that is result the The However, system. brake unavailable. Pressure builds in the main the in excess builds vents Pressure reservoir main normal levels. Safety valve on valve Safety levels. normal pressure. Fail on Fail Fail brakes cm brakes Fail Fails off Fails Fail off Fail on Fails Failure Mode Failure off brakes Fail Compressor (2) Compressor (Acts Intercity 225 (Great Britain) Britain) (Great 225 Intercity (Disc Component Brakes Disc 11 of 5 Page and MRS governor MRS and independently on Air each brake wheelset) for independently each applied cylinder or caliper, 3 discs 3 caliper, or Tread Brakes Tread unit per axle) per 3-95 D S C C D D FS Y Y Y Y Y Y FT N N Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; =Y Safe; Fail = FS Tolerant; Fault =FT Gauges in cab indicate high pressure. high indicate cab in Gauges How Detected/Response How Assume driver has indicator of also. can cab in and indicator cab has in operation driver Assume operation compressor compressor of Safety valve senses overpressure and overpressure of senses pressure valve low Safety indicate of cab in pressure Gauges low indicate cab in Gauges vents to 10 bar pressure in reservoir. in pressure bar indicator 10 has to vents driver compressors. Assume via indicator also. has pressure cab reservoir. in charge driver Assume operation compressor reservoir. of detect valve failure. Repair at first at Repair is failure. energy valve detect sufficient ensure to MRS Inspection and maintenance should of maintenance and pressure Inspection indicate cab in Gauges available to stop the train. Driver can Driver train. the stop to available maintenance opportunity. maintenance build up or safety valve relieves pressure valve relieve to safety or MRS/MRP up vent build pressure. Effect on Overall Braking System Braking main on Overall on valve released be Effect Safety not None. may brakes Friction the correct pressure. correct the Air is vented from main reservoir main from vented is Air or excessive running of compressors of running result. will excessive both or or reservoir acts to vent the reservoir to reservoir the vent to acts reservoir resulting in low pressure in main in brakes pressure result. low in will Friction both or resulting reservoir. compressors unavailable or excessive running of running second excessive a or requires unavailable This vent effect. should No valve safety MRS Hie failure for this failure to have any have to in failure this pressures for safe failure impact. maintain to air MRS. the the Table 3-12. Intercity 225 F225 M Intercity 3-12. Table E A(conk) Effect on Braking Subsystem Braking on Effect May not be able to re-energize to able be not May pressure reaches 10.7 bar to reservoir 10 once of bar main on 10.7 pressure pressure valve reaches excess Safety desired vents pressure maintain brake system. The result is that be is to cannot tiy result may The hard brakes system. Compressors running friction by brake the released. compensate reservoir. Friction brakes will both Friction or reservoir. compressors of resulting in low pressure in main in pressure low in resulting Air is vented from main reservoir main from vented is Air bar in reservoir. in bar trying to reach the desired 10 bar. 10 desired the reach to trying unavailable or excessive running excessive or unavailable result. safety valve failing closed occurs, closed failing valve safety No effect. If a combination of and combination a If effect. No overpressurization MRS there would be no relief for MRS relief in no up be build would levels. could there excessive Pressure to overpressurization. Fails low pressure low Fails Fails high pressure high Fails Failure Mode Failure Fails open Fails Fails open Fails closed Fails Intercity 225 (Great Britain) Britain) (Great 225 Intercity Component 11 of 6 Page Main Reservoir (MRS) Main Supply MRS Safety Valve Safety MRS Pressure Control Pressure Valve 3 - 9 6 c S D D D D of 11 of FS Y Y Y Y7 Y Page 7 Page N Y FT Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; =Y Safe; Fail = FS Tolerant; Fault =FT Gauges in cab indicate pressure of pressure train. indicate the cab checks. stop in to Gauges inspection available and Maintenance MRS to ensure sufficient energy is energy sufficient ensure to MRS How Dctected/Response How checks. inspection and of Maintenance can ABP pressure levels train. indicate the cab pressure stop in to Gauges indicate cab available in Gauges MRP to ensure sufficient energy is energy reservoir. sufficient supply ensure to brake MRP ABP. charge via reservoir to driver. Initial response is charge is response Initial driver. to supply. Effect on Overall Braking System be Braking if cannot loss Overall brakes on applied. pressure once Effect friction and The maintain leak released compensate and This air can supply valve air makeup air system. based drain the Potential air with in to open compressor mixes responses for moisture moisture brake of Condensate adding amount changing ABP. and the on the ABP. brake via the the distributor friction via distributor the the reservoir recharge reservoir supply remains, release cannot the reservoir, MRP to If pressure supply unable low recharges be If will no condensate is present. Assume present. is condensate components no on wear in pressure. so MRP in result may available not is Pressure the distributor recharges the brake the recharges distributor the truck. the for brakes Table 3-12. Intercity 225 F225 M Intercity Table3-12. E A(cont.) so that once the friction brakes friction the once that so responses based on the amount of brake amount the changing on and based components responses If MRP cannot recharge the brake the distributor the recharge cannot reservoir, MRP If supply Potential air leak and pressure and leak air supply air Potential with mixes Condensate ABP. are applied, they may not be able Subsystem be not Braking on may they present. Effect is applied, are condensate no system. if air loss to moisture adding This may result in wear on wear in supply. result air may the This in moisture so the distributor recharges the the recharges via the reservoir the via distributor to for the supply so unable reservoir brake brakes be the will friction recharges the distributor release tmck. to be reapplied because of the of because reapplied be to become may System corrosion. remains, pressure low If ABP. Pressure is not available to MRS to available not is Pressure to leading contaminated, Pressure is not available in MRP in available not is Pressure pressure deficiency in the MRP. the in deficiency pressure Fails with low with Fails Fails open Fails closed Fails Fails closed Fails Fails with low with Fails Failure Mode Failure pressure . pressure pressure Automatic Drain Automatic Intercity 225 (Great Britain) (Great 225 Intercity Brake Supply Brake Component Valves Reservoir Main Reservoir Main Valve Pipe6 Pressure Control Pressure 3-97 S B3 A3 A3 B3 D A3 N N FS N N Y N N FT Y N Y Y N S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; =Y Safe; Fail = FS Tolerant; Fault =FT Inspection and maintenance are the are the maintenance of and Detected/Response aware How be only Inspection will Operator situation if the braking response is response braking the if situation means of detection. If the braking the If detection. of means in resulting high too is effort Braking level is incorrect, the operator will operator the incorrect, is compensate. to level have obviously different from what was the what If maintenance from and detection. different of Inspection means obviously the desired. are will have to compensate. to have will reduce level of braking requested. If possible, If requested. braking decrease. of speed level rapid reduce braking level is incorrect, the operator the incorrect, is level braking reservoir via ABP. via reservoir Coach does not brake sufficiently. brake not does Coach isolated, operator can continue at continue can operator speed. speed. line reduced isolated, at reduced Continue Braking effort is too high resulting in resulting high too is effort Braking Gauges in cab indicate pressure levels pressure indicate cab in Gauges WSP is locked out and distributor and out locked is WSP to driver. Initial response is charge is response Initial driver. to braking requested. WSP may lockout, may WSP requested. braking coach. rapid speed decrease. Reduce level of level Reduce decrease. speed rapid may need to isolate brakes on this on brakes isolate to need may system if the drain valves cannot valves drain the if system May potentially freeze up a valve or antifreeze. valve a excess up the of freeze dispose potentially May Effect on Overall Braking System the Braking are contaminate Overall on brakes the Effect potentially that May so line control not applied to the desired level. desired the to brakes applied not distributor failed with Coach too much, overworks WSP for the for WSP overworks much, too Braking effort is too low for the for the low for too is available effort not Braking brakes Friction truck. WSP lockout may occur may lockout WSP truck. coach. Decrease in speed beyond level beyond speed in Decrease desired. possibly isolating the distributor. the isolating possibly coach. Table 3-12. Intercity 225 F225 M Intercity 3-12. Table E A(cont.) system if the drain valves cannot valves a drain is the there if system weather colder In dispose of the excess antifreeze. excess the of dispose May potentially contaminate the contaminate potentially May freezing in a valve or air line. air or valve a in freezing Braking occurs above desired above occurs Braking Effect on Braking Subsystem Braking on Effect potential of moisture in the air the in moisture of potential Wheelslide coach. wear brake the on for Excessive level overheating possible. wheelslide. and/or components ABP. If low pressure remains, pressure low If ABP. the coach effected including no including effected coach the protection (WSP) prevents (WSP) protection distributor the the the via recharge reservoir reservoir, cannot the MRP If desired auxiliary above recharges occurs Braking distributor will be unable to apply to unable be will distributor compensate to avoid wheel slip. wheel avoid to compensate braking. the friction brakes for the coach. the for brakes friction the level for the coach. WSP should WSP coach. the for level Braking is under desired level for level desired under is Braking Insufficient amount antifreeze Insufficient of Failure Mode antifreeze Failure much Too Signal for too little fails too for braking, low no Signal or with closed. Fails Signal for braking level, for desired open. Signal above fails Signal for too much too coach. for the Signal for exists pressure indicates than load braking, higher (Winter only) (Winter Intercity 225 (Great Britain) Britain) (Great 225 the Intercity into Component System Antifreeze Air 11 of 8 Page Distributor Addition of Addition Auxiliary coach) each Trailer Coach Trailer Relay Valve (1 for Load (1 Valve Variable Relay Reservoir8 Stage Two 3 -9 8 B3 B3 S A3 C A3 B3 N Y FS N N N N Y N Y N FT N Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT speed depending on degree of failure. of degree on depending speed applies brakes. applies speed depending on degree of failure. of degree on depending speed and continue at reduced speed or line or speed reduced at continue and requested. Driver could isolate system isolate could Driver system requested. isolate could Driver requested. Train does not slow quickly enough. braking quickly of slow not level Detected/Response does How increase Train Must speed requested. than reduced at effort operate braking to have Lower speed requested. May than reduced at effort operate automatically braking to Lower have signal, May loses system If requested. For no indication of load, of indication no For of requested. degree on depending speed of line or degree on depending speed line or speed limit of 161 km/hr is imposed. is km/hr 161 of limit speed and continue at reduced speed or line or speed reduced at continue and Potentially, speed reduction when not when reduction speed not when Potentially, reduction speed failure. Potentially, failure. Full brakes applied by system from system by applied brakes Full Effect on Overall Braking System increasing Braking low, too Overall is on disc. effort 1 Effect distance. from braking from Braking stopping lost effort effort to to is applied, disc. not equivalent applied one equivalent from effort braking from Brake constantly lost disc. effort capability effort to one to effort applied, Brake not equivalent equivalent effort (DVT). Brake disc. capability one Trailer Van Driving the Excessive wear on discs, calipers, discs, on possible. wear wheels even Excessive and Brake effort constantly applied is applied constantly effort Brake Table 3-12. InterCity 225 F225 M InterCity 3-12. Table E A(cont.) (DVT). Excessive wear on brakes and/or brakes on wear disc. Excessive one system from by effort applied brakes Full Brake effort not applied, lost applied, not effort Brake Braking is under desired level for level desired under is Braking equivalent to effort from 1 disc. 1 from effort to disc. equivalent one disc. one from from effort to effort equivalent Trailer Van Driving the from Brake effort constantly applied is applied effected. coach and/or the lost constantly brakes on effort is wear applied, Brake not applied Excessive effort to Brake constantly effort equivalent Brake capability braking Effect on Braking Subsystem Braking on Effect possibly overheating of brakes. of overheating possibly braking capability equivalent to equivalent capability braking possibly overheating of brakes. of overheating possibly signal transmitted to transmitted signal DVT. Loss of braking of Loss Fail discs brakes on brakes discs off Fail brakes disc Fail on brakes Fail off brakes Fail Signal for too little too for Signal exists. lighter or no load for Mode load indicates no Failure really or than braking, coach lighter the Driving Van Driving same signal as sent as signal same Trailer (normal Trailer Communication to TDM transmits Communication operation from Driver’s Controller) from Brake Driving Van Trailer9 Van Driving or caliper, 3 discs 3 caliper, or Intercity 225 (Great Britain) Britain) (Great 225 Intercity Component 11 of 9 Page per axle) per Disc Brakes (Disc Brakes Disc Variable Load Variable (One Brake Disc Actuators Two Stage Two coach) each Relay Valve (1 for (1 Valve Relay disc) per 3-99 S A3 B3 A3 D D D D N N FS N Y Y Y Y FT N Y N Y Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Braking effort is too high resulting in of resulting level high too Reduce is decrease. Detected/Response effort How speed Braking rapid braking requested. braking Train does not slow quickly enough. braking quickly of slow not level does increase Train Must requested. Train does not slow down. Must down. slow not does applied. Train is braking Emergency utilize emergency brake. emergency utilize Emergency braking is applied. is braking Emergency Assume some fault is noted so that on that so noted is fault some Assume Inspection and maintenance should plunger. the of maintenance and failure any Inspection correct next available maintenance opportunity maintenance fixed. be available can next fault Effect on Overall Braking System Braking increasing Overall on low, too Effect is effort distance. Braking stopping Rapid decrease in speed beyond speed in decrease all. at Rapid occur not does Braking level desired level Emergency braking is applied. is braking Emergency Emergency braking is applied. is braking Emergency Emergency braking is applied. is braking Emergency No effect. Emergency brakes are brakes Emergency effect. No controller. Plunger is a backup. a is Plunger controller. normally applied via brake via applied normally Table 3-12. Intercity 225 F225 M Intercity 3-12. Table E A(cont.) Effect on Braking Subsystem desired Braking above on tmck. occurs the Effect for Braking sliding Braking does not occur at all for all at occur not does Braking level. May result in some wheel for some in level result desired May under level. is Braking the truck effected. truck signal, the electric to addition In the affected tmck. affected the controller directly vents the ABP the vents position. directly emergency the in controller applied. when still Therefore, emergency braking is braking emergency Therefore, Emergency braking is applied via applied is braking Emergency controller directly vents the ABP signal, the vents electric position. to directly emergency addition the In in controller applied. when still emergency braking is still is braking emergency Therefore, emergency braking is braking emergency Therefore, applied. a backup. a the electric signal. Therefore, are signal. is brakes electric plunger the Emergency Emergency effect. No controller. normally applied via brake via applied normally No signal for signal No Signal for too much Mode too for Failure little too Signal braking for Signal braking when requested. braking braking braking. Signal for too little too for Signal for signal No Venting does not does Venting ABP. vent not Does braking. braking when requested. braking braking occur with controller with emergency occur in position. Intercity 225 (Great Britain) Britain) (Great 225 Intercity Load Component Variable truck) each 11 of 10 Page Relay Valve (1 for (1 Stage Two Valve Relay Driver’s Brake Driver’s Controller Emergency Plunger 3 - 1 0 0 A2 C S C N Y FS Y N N N FT S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S IT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; =Y Safe; Fail = FS Tolerant; Fault =IT required. Emergency brake not initiated. Driver to initiated. action not take Detected/Response brake to How Emergency seconds 3 has Driver cancel the hom or the ABP is ABP the or hom the cancel receives notification of valve operation if valve of braking emergency notification select can receives and ABP is automatically vented initiating vented automatically is ABP automatically vented. braking. automatically emergency Driver receives notification of valve System of Braking emergency initiated. Overall action not notification on select take brake can to Effect and receives Emergency seconds Driver 3 operation has Driver to cancel the hom or the ABP is ABP the required. or if hom vented vented. the braking. braking cancel emergency to automatically automatically is ABP initiating Table 3-12. Intercity 225 F225 M Intercity Table3-12. E A(cont.) emergency braking if required. if braking emergency ABP is automatically vented automatically is ABP Driver receives notification of Subsystem initiated. Braking not notification on take brake to Effect receives vented. Emergency seconds Driver 3 has automatically Driver is ABP valve operation and can select can and operation valve initiating emergency braking. emergency initiating action to cancel the hom or the or hom the cancel to action Driver does not does 60 Driver every once seconds. ABP not vented not not ABP signal Lineside activate foot pedal foot activate Failure Mode Failure when operated. when sounds. hom green, Automatic Safety Driver Device Intercity 225 (Great Britain) Britain) (Great 225 Intercity Component Vent Emergency Valves 11 of 11 Page Warning System Warning Passenger 10. This section only includes modes of triggering emergency braking because the actual application of the emergency brakes is done via the systems described above. described systems the via done is brakes emergency the of application actual the because braking emergency triggering of modes includes only section This 10. 1. Even though this failure results in the friction brakes being applied, this failure may not be failsafe if it occurs at high speeds. high at occurs it if failsafe be not may failure this applied, being brakes friction the in results failure this though Even 1. 8. Auxiliary reservoir always recharged before air supplied to air suspension. air to supplied air before recharged always reservoir Auxiliary 8. 3. WSP control locks out dump valve if continuously dumping for 10 secs and applies full brakes until train stopped or all wheelsets within 10 km/hr of each other. each of km/hr 10 within wheelsets all or stopped train until brakes full applies and secs 10 for dumping continuously if valve dump out locks control WSP 3. 9. Same as trailer coach except as noted. as except coach trailer as Same 9. 5. Typically friction braking on a motor tiuck is only used for speeds below 30 mph, unless the iheostatic brake fails. brake iheostatic the brakes. unless mph, 30 friction train. below using stop speeds to braking for used available only rheostatic is pressure without tiuck motor safely a sufficient on stopped ensure be braking to still can monitored friction Train 4. Typically continuously 5. MRP 6. 2. BCU recharges ABP at a rate much less than the rate of air loss from safety system activation. system safety from loss air of rate the than less much rate a at ABP recharges BCU 2. 7. Failsafe if distributor automatically recharges brake supply reservoir via ABP when MRP has low pressure. low has MRP when ABP via reservoir supply brake recharges automatically distributor if Failsafe 7. 3-101 3.7 SHINKANSEN TRAINS 3.7.1 Description of Trainsets Since the inauguration of service on the N e w Tokaido Line in 1964, the Tokaido Shinkansen h as carried over 2.5 billion passengers. T o this original line b e t w e e n T o k y o a n d O s a k a , three other lines have been added: the Sanyo line, Osaka to Hakata (Kyushu); the Joetsu to Niigata; and the Tohoku line to Morioka and eventually to Sapporo (Hokkaido). Three different series of trainsets are used in service. T h e 100 series trains consist of 12 motor cars (all axles powered b y dc traction motors) and four trailer cars with a trainset weight of 925 metric tons. These are run in service at 220 km/h (137 mph) m a x i m u m speed, however, newer cars in current use on the Tokaido line are run at 240 k m/h (150 mph). A 2 0 0 series in 12-car trainsets h as all axles p o w e r e d b y slightly m o r e p o w e r f u l m o t o r s (230 k W vs. 185 k W ) than the 100 series to cope with steeper gradients on other lines. Finally, the newest 300 series in the “N o z o m i ” service has increased the top speed from 220 to 270 k m / h (168 mph). This trainset consists of 12 motored cars (all axles powered by ac cage a s y n c h r o n o u s traction motors) a n d four trailer cars. B y use o f a l u m i n u m car structures, the trainset weight has been reduced to 7 10 metric tons. 3.7.2 Braking System Design T h e three S h i n k a n s e n trainset series app ly s o m e w h a t different braking s y s t e m design philosophies. These differences are noted in Table 3-13 (Ref. 22). T h e newer 200 series cars m a y have incorporated s o m e of the features of the 300 series brake design. Prior to 1978, the electric cars in S h i n k a n s e n service w e r e e q u i p p e d w it h a straight air pipe s y s t e m of air brakes. Since 1978, a n all-electric c o m m a n d b r a k e control s y s t e m has b e e n used, starting with the 1 0 0 series cars. B r a k e sys te m s of all three series (100-300) are ba s e d mechanically on a pneumatic/hydraulic conversion disc brake, supplemented by dynamic (rheostatic or regenerative) braking on powered axles and eddy current brakes on non- powered trailer car axles. Cars carry two wheel cheek-mounted discs per axle. T h e electro p n e u m a t i c c h a n g e o v e r valve receives a n electric current c o m m a n d , converting this to a n air pressure c o m m a n d , which is amplified by the relay valve. In the air-hydraulic booster, air pressure is converted into pressurized oil. T h e mechanical friction brake calipers are then actuated b y a n hydraulic cylinder. T hi s s e q u e n c e is illustrated in the schematic diagram, Figure 3-9, for the 2 00 series cars (Ref. 23). 3.7.3 Brake System Performance T h e specified train deceleration rates for the 2 0 0 a n d 3 0 0 series trainsets cor respond to given speed-adhesion characteristics to account for decreasing wheelset adhesion above a speed of about 80 km/h. Nominal braking rates for these trainsets are compared in Table 3-14. Speed versus deceleration characteristic curves for the Series 3 00 trainset are s h o w n in Figure 3-10 (Ref. 24). 3-102 Figure 3-9. Schematic Diagram of Series 200 Trainset Brake System (Ref. 23) 3-103 Table 3-13. Braking System Design Overview for Shinkansen Trainsets T r a i n s e t Brake System Design Attributes 1 0 0 • Rheostatic (dynamic) braking • Electrically-controlled air brake system • Eddy current brake system on trailer cars • Continuous control along adhesion pattern 2 0 0 • Rheostatic (dynamic) braking • Electro-magnetic straight air brake system • Continuous control to, A T C speed step 3 0 0 • A.C. regenerative (dynamic) braking • Electrically-controlled air brake system • Eddy current brake system on trailer cars with load response device • Continuous control along adhesion pattern Table 3-14. Nominal Braking Rates for Shinkansen Trainsets Series 2 0 0 Series 300 (Nozomi) Condition Below 70 km/h, At 220 km/h, B e l o w 8 0 km / h , At 270 km/h, km/h/s (mph/s) km/h/s (mph/s) km/h/s (mph/s) k m / h / s (mph/s) Full Service 2.6 (1.6) 1.3 (0.8) 2.6 (1.6) 1.3 (0.8) E m e r g e n c y 3.9 (2.4) 2.0 (1.2) 3.6 (2.2) 1.8 (1.1) U r g e n c y 2.8 (1.7) 2.8 (1.7) 2.9 (1.8) 2.2 (1.4) 3.7.4 Braking System Operation. Control and Safety Features Operation and Control T h e brake system for the Series 200 cars is controlled by electric c o m m a n d s over eight c o m m a n d levels carried over the train b u s (Figure 3-9). C o m m a n d s for braking effort ra n g e in se v e n steps ( I N to 7 N ) u p to full service braking, using a grey c o d e (three-wire) system. A separate line c o m m a n d s the eighth ( e m e r g e n c y ) level. A separate “ u r g e n c y ” brake circuit controls the brakes of a car in abnormal conditions, such as train separation, electric p o w e r loss, or a shortage of brake force. T h e seven service brake levels are energized in sequence as c o m m a n d e d by the driver’s brake controller or by the automatic train control (ATC). The emergency brake line is normally energized and is deenergized w h e n emergency braking is commanded. Braking force in emergency is 50 percent higher than in full service (7N) braking. The urgency brake is also c o m m a n d e d from a normally energized line. 3-104 Deceleration (km/h/s) F i g u r e 3-10. S p e e d vs. Deceleration Characteristics Deceleration vs. d e e p S 3-10. e r u g i F for t he Series 3 0 0 ( N o z o m i ) T r a i n s e t (Ref. 24) (Ref. t e s n i a r T ) i m o z o N ( 0 0 3 Series he t for pe (km/h) Speed 3-105 T h e braking c o m m a n d line signals are interpreted by the brake pattern generator which, in conjunction with the signal from a tachometer-generator ( S G in Figure 3-9) and the locally- stored speed-adhesion characteristic, sends a s pe ed -modified signal to the c h o p p e r control equipment. This controls the electric brake unit and the electro-pneumatic changeover valve amplifier. Priority blending of brakes uses the d y n a m i c (electric) braking to its m a x i m u m level to reduce wear on friction brake components. Speed-adhesion characteristics and anti skid control modulate the braking force to avoid sliding the wheels. T he urgency brake is applied from its normally-energized c o m m a n d line by a one-step control at any speed and the speed pattern control is not applied. Urgency braking is applied only to the car in abnormal operation, while emergency braking is applied to all other cars with the corresponding speed-adhesion a n d antislip controls. A n auxiliary bra ke is available to enable the train to b e ru n at ve r y s l o w speeds in the event that service a n d e m e r g e n c y b ra ke s y s t e m s are inoperable. This is a simple four-step control in the 200 series. A s n o w brake is used to prevent s n o w and ice sticking and freezing on the brake shoes in the winter season. In the Series 3 0 0 cars, both the service a n d e m e r g e n c y bra ke levels are des ig n ed to control the braking force according to load condition and individual car weight condition, in addition to the speed-adhesion characteristics (Ref. 2 4 ) . T he urgency brake uses a two-step control to compensate for lower adhesion at higher train speeds. T h e service brake usually applies the electrical (regenerative d y n a m i c ) brakes with the pneumatic/hydraulic p o w e r e d friction brakes taking over in the lower speed range. Emergency braking force is 40 percent higher than the full service ( 7 N ) braking level. C o m m a n d of the service and emergency braking is applied b y the driver’s brake controller or the A T C s y s t e m as illustrated in Figure 3-11. T hi s figure implies a seven-wire service br a k e train line, energized in a progressive sequence. Again, the emergency brake line is normally energized, a n d deenergized to c o m m a n d e m e r g e n c y braking (a fail-safe approach). T h e s e c o m m a n d s are directed to the brake output controller of each car. Both service and emergency brakes employ a variable load controller which detects the car suspension air spring pressures at the four locations o n each car. T h e auxiliary brake on the 300 series cars allows low-speed operation w h e n service and emergency brakes are inoperable. This brake uses a three-step (two-wire) control of braking force. Leading cars of the Series 300 and older Series 0 cars have brake interface equipment so that they can operate in a “rescue” mode. 3 . 7 . 5 Braking System Effects on Vehicle. Guidewav, and Infrastructure T h e S h i n k a n s e n trainsets d o not use track brakes s u c h as the electro-magnetic or linear e d d y current emergency brake systems used on s om e high-speed trains. Although the trainsets use eddy current disc brakes o n trailer car axles, no detailed description of these brakes has been found in the literature. Possible problems with electro-magnetic (EMI) or radio frequency (RFI) interference have not been mentioned. 3-106 Braka control* Figure 3-11. Schematic Diagram of Series 300 (Nozomi) Trainset Brake System (Ref. 24) 3-107 S c B3 B3 A2 B3 D A2 C D Page 1 of 5 of 1 Page Y 1)N FS N N 2)N Y N Y Y N 1)N FT Y Y 2)Y Y N N Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; =Y Safe; Fail = FS Tolerant; Fault =FT Signal in cab? Driver realizes Driver Detected/Response How cab? in Signal train not slowing at proper rate. proper rate. at realizes proper slowing at Driver not cab? slowing in train not cab? Signal in train Signal By inspection? By Loss of braking. Signal in cab. in Signal braking. of Loss Signal in cab? in Signal applied. Auxiliaty the that Emergency-brakes assumed is It Signal in cab. ATC in or operator. Signal Unit the Command signal Brake will 1) Possible overbraking and slip at high at slip and overbraking Possible 1) Driver must increase braking effort to effort to braking effort braking increase must increase Driver must Driver device fails. If Anti-Skid device fails, compensate. to device compensate. wheels to Anti-Skid other for wheels If higher. Device other fails. device Anti-Skid See substantially 2) speed. Effect on Overall Braking System Braking Overall on Effect probability of locking wheels is Anti-Skid wheel wheels unless locking of Negligible effects. probability possible other The effect should be negligible at high at be may braking negligible be train the should Urgent-brake Electrodynamic and however, where effect normal-service The Emergency used; speeds lose is the cars apply more or One All brakes applied to comfortably stop comfortably to the Service applied activate brakes may Emergency All unit ATC The forced to decelerate more quickly or quickly more decelerate to speeds. forced lower at emergency brake if it senses that the distance. that braking senses minimum it in if decelerating. brake train not is emergency train braking including Electrodynamic including braking braking. Emergency/Urgent-brakes braking. need to be applied to slow/stop train. slow/stop to applied be to need Table 3-15. Shinkansen3-15. TableF200 M E AWorksheet 1) Sends incorrect "no slip" signal to signal slip" "no incorrect Sends 1) Effect on Braking Subsystem Braking on Effect speed. Anti-skid Valve should Valve Anti-skid speed. Brake power reduced to counter slip. counter to reduced power Brake Braking level not adjusted for train for adjusted not Circuit level Braking Generating Pattern Adhesion Wheel begins/continues to slide with slide to power. brake begins/continues of Wheel loss prevent wheel slip. wheel in prevent lost is deceleration of degree A slip. 2) Causes Anti-Skid device to device Anti-Skid (See Anti-Skid slip Causes detect 2) slip. improperly Device). Loss of normal service braking. service emergency normal of causing Loss wire Deenergizes applied. not Brakes possibly resulting in overbraking at overbraking in resulting either possibly requiring cars all or some higher speeds and possible wheel possible and speeds higher under- or over-braking. or under- brakes to apply. to brakes Fails to detect slip detect to detects Fails Incorrectly slip Fails to send signal send to Fails signai/Improper Failure Mode Failure All three lines fail lines three All calibration to fails line One Fails to carry to signal Fails send signal to Fails Sends incorrect Sends signal carry Braking Control Braking Shinkansen 200 (Japan) 200 Shinkansen Component Brake Controller Brake (Anti-skid) Device (Anti-skid) Emergency-brake Bus (3 wires) Electrical (3 Bus Tachometer- Signal) Wheel-slip Generator (Speed Generator Wiring/Train Data Wiring/Train Wire 3 - 1 0 8 D A2 D B3 A2 S D C N N Y N Y Y Y FS Y N Y N Y Y N FT S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; =Y Safe; Fail = FS Tolerant; Fault =FT signals will be activated in the in warning the that activated in be warning assumed will is that activated It be signals assumed will is It signals cab. cab. Signal in cab? Loss of brake of Loss cab? in Signal Brake Command Unit or ATC or Unit Command Brake deceleration. train Unusual Signal in cab? Loss of brake of Loss cab? in Signal power. It is assumed that the Auxiliary the that operator. Detected/Response assumed the How is It signal will cab? to Signal power. Friction brakes are sufficient to stop to activated. be sufficient must are brakes brakes Friction Friction speeds. Operator may need to engage Brakes to need may Electric stop Operator activate to to activated. speeds. be signal sufficient must are since brakes brakes Friction Friction the train. train. < the Disproportionate braking. Auxiliary braking Service: braking. Emergency Service: Regenerative which ineffective. Emergency braking. at Disproportionate braking are of Service: speeds auxiliary systems loss of Emergency total Loss in Urgent-/Emergency-brakes. result May train. the Braking is disproportionately applied. emergency detected, may is disproportionately is Operator low failure at a Braking braking. If of travel to loss low train at Possible allow only ineffective brakes brakes unit. this Regenerative through pass must be required to manually apply brakes. apply manually to required be Effect on Overall Braking System Braking Overall on applied. be Effect will braking Table 3-15. ShinkansenTable3-15. F200 M E AWorksheet (cont.) Loss of dynamic braking. dynamic of Loss Braking level not changed. May changed. not level Braking braking. dynamic of Loss result in lack of brake application or application brake of release. lack in brake of result lack when the Brake Controller has failed, has or over- Controller in valve, applied. Brake not the resulting are changeover when applied brakes friction Electro-pneumatic and ATC may still activate brakes. activate still disproportionately may be ATC will brakes Since this controller only operates only controller this to on Since passed not under-braking. Signal It is assumed that some correction some that assumed is It None, unless Brake Controller has failed, have Controller systems Brake both unless If None, failed. Effect on Braking Subsystem Braking on Effect will be made by the brake pattern brake the by made be will generator to account for speed and speed for account to generator adhesion. Brakes may be may Brakes adhesion. over-/under-applied. signal Off Fail failure, seizes. Bearing axle Fails to process to Fails signal process to Fails Sends incorrect Sends signal incoming Fails to send signal send to Fails Sends incorrect Sends signal Failure Mode Failure Resistive (Dynamic) Brakes (Power Cars) (Power Brakes (Dynamic) Resistive Motor/Generator) Change Circuit Change Brake (Traction Resistive System Brake Notch Brake Auxiliary Brake Auxiliary Car) Receiving Unit (per Unit Receiving Auxiliary Brake Unit Auxiliary Command Shinkansen 200 (Japan) (Japan) 200 Shinkansen Component Controller Brake 5 of 2 Page 3 - 1 0 9 S B3 B3 B3 D D B3 C N FS N Y N Y N Y Y1 FT Y Y1 Y Y Y N S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No =N Yes; =Y Safe; Fail = FS Tolerant; Fault =FT Unusual braking performance. Detected/Response How braking Unusual Signal in cab? in Signal Unusual braking performance. braking Unusual Signal in cab? in cab? Signal in Signal Signal in cab? in Signal Signal in cab? Inspection? cab? Valve? in Transfer Signal and Valve Pressure sensor between Relay between sensor Inspection? Pressure cab? in Signal Effect on Overall Braking System Braking requires Overall on situation Effect the If optimized. Regenerative brakes should already be already should brakes Regenerative applied. be must used be brakes must Emergency Emergency/Urgent-brake friction braking, feedback will increase will deceleration is be proper feedback must braking until more brakes braking, If effort emergency friction achieved. braking is required, applied. Regenerative braking slows train from train slows braking Regenerative Emergency/Urgent-brake may have to have may Emergency/Urgent-brake Friction brakes on effected car cannot car effected on brakes Friction Regenerative braking slows train from more speed. train low but at slows speed, train braking under-amplified, high stop If to speed. Regenerative high None. car. Electrodynamic brakes unaffected. brakes Electrodynamic Regenerative braking will slow train at slow brakes will of Loss braking speed. high Regenerative from friction-brake force must be applied. be speed. must low at force train stop to friction-brake used be be released once applied. once released be Table 3-15. Shinkansen3-15. TableF200 M E AWorksheet (cont.) Effect on Braking Subsystem Braking on under-applied. Effect are Brakes Electric signal not converted to air to car. at converted to not braking due of signal Loss under-applied Electric or over- Brakes pressure. Loss of braking at car. at braking of Loss pressure. amplification. improper Air pressure not sent to Transfer to be sent not cannot car None. pressure Air effected on Brakes Changeover Valve. Changeover acts as check valve to prevent back prevent to valve check as acts Valve. Friction brakes not applied. not Valve brakes Relay Friction applied. Valve. once released pressure to Electro-pneumatic to pressure Fails to amplify to Fails Fails as Open as Fails Circuit Failure Mode Failure Fails Open Fails Fails Off Fails Improper Calibration Fails Closed Fails Open Fails EledtrO-pHeumattc/Tricliim (rawer Cars) (rawer EledtrO-pHeumattc/Tricliim Electro-pneumatic Shinkansen 200 (Japan) (Japan) 200 Shinkansen Component 5 of 3 Page Amplifier for Amplifier Changeover Valve Changeover Relay Valve Relay Changeover Valve Electro-pneumatic Changeover Transfer Valve/Vent Transfer 3 - 1 1 0 B3 S B3 B3 D A3 B3 A2 B3 B3 N N FS N Y N N N N N Y Y Y FT Y Y Y N N Y2 S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT Lack of braking. Oil pressure Oil is braking. of situation Lack This sensor? Inspection? Inspection. cab? in Signal Oil pressure sensor? Detected/Response How pressure Oil Inspection? cab? in Signal Thermocouple at discs? Warning discs? at Thermocouple light? cab? in Signal cab? in Signal probably unnoticeable. probably compensate with Friction braking to braking Friction with train. compensate stop negligible. be should In severe case, friction braking could braking friction case, severe In Effect on Overall Braking System Braking Overall on to Effect braking effect Friction of with compensate, number does train. on compensate stop feedback depends If caliper/disc to of effected. reduction damage of number discs on cause of May depends number on of reduction depends number of on effected. reduction depends of discs reduction of Regenerative braking will slow train slow must will cars train Other braking slow must will speed. cars high Regenerative Other braking from speed. Amount high Regenerative power. from braking in Amount Reduction power. Amount braking power. in Amount braking effected. Reduction power. in discs braking Reduction in effected. Reduction discs resulting in reduction of brake power. brake of reduction in resulting be lost on that car. that on lost be Table 3-15. Shinkansen3-15. TableF200 M E AWorksheet (cont.) Increases wear to calipers. Possible calipers. to wear Increases Friction brakes not applied at applied not brakes discs. Friction compensates affected Feedback the at spots braking Over-brakes. flat of Loss develop may wheels speed, Calipers modulated, reducing or valves modulated, in Calipers failure cause May effected car. effected pressure? air causing high at possibly lessening by up, locks-up heat axle will If fire. Disc damage. catch or power. braking available Air pressure not converted to Subsystem car. converted Braking not on effected at Effect pressure Air braking friction No braking power. braking Axle locks-up, providing limited providing locks-up, Axle hydraulic-oil pressure at Booster. at pressure hydraulic-oil disc. that at braking of loss car. that in braking friction pneumatic lines resulting in loss of loss in resulting lines pneumatic Incorrectly senses Incorrectly slip Fail to apply Over-amplifies/too to open) Fail (stuck Fails to sense loss Fracture sense to traction Fails of regulate to pressure Fails (limit) much oil pressure oil much release to closed) Fail (stuck Fails Closed Fails to Fails oil pressure amplify/produce oil Failure Mode Failure (Traction Control) (Traction Valve Brake Discs Brake Disc Brake Calipers Brake Disc Shinkansen 200 (Japan) (Japan) 200 Shinkansen 5 of 4 Page Generating Circuit Generating Regulating Pressure Adhesion Pattern Adhesion Booster Component Transfer Valve/Vent Transfer 3-1 11 C S B3 B3 B3 B3 B3 B3 C Y FS N N N Y N N N. N Y FT Y Y Y N Y Y S = Failure Mode Severity, described in Section 2.2 Section in described ModeSeverity, Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No N= Yes; Y= Safe; Fail = FS Tolerant; Fault =FT How Detected/Response How Signal in cab (or lack of signal) of cab lack in (or Signal cab in Signal cab? in Signal Pressure gauge in cab7 in gauge Pressure Inspection Inspection Inspection Inspection Train begins to brake. Signal in Signal brake. to begins Inspection. Train cab. Pressure gauge in cab? in gauge cab? Pressure in cab? gauge in gauge Pressure Pressure Effect on Overall. Braking System Braking be should Overall. on in brakes Service: Effect reduction Emergency 8% be Service Electrodynamic must Emergency Approximately Service Emergency Emergency/Urgent-brake available friction braking. Other cars wear. Other minimize braking. to applied friction train. increased available stop cars to increased Service other cars applied in Emergency other effort in Braking effort Braking Train brakes regardless of condition of condition of regardless in braking. in brakes equipment service result Train may increased damaged normal This or compensate. cars increased to in lines other compensate. cars in to equipment raptured other effort in over-pressurization. damaged or Braking effort lines Braking ruptured over-pressurization. must compensate. must the effected car due to due car in effected result the may to This due compensate. to car compensate. to effected the Table 3-15. Table Shinkansen3-15. F200 M E AWorksheet (cont.) Friction brakes applied on car. on applied brakes unusable. Friction Urgent-brake one or more cars. more or one Disables auxiliaty friction braking on braking friction emergency auxiliaty the causing in wire Disables braking Deenergizes friction of Loss Effect on Braking Subsystem Braking on Effect affected car. affected brakes to apply. to brakes the in the braking in braking friction of Loss friction of Loss Loss of friction braking in the in braking car. friction car. affected of Loss affected car. affected Fails to cany to Fails cany signal to Fails signal (clog) Closed Fail Fails Open Fails Closed Fails Fail Open (leak) Open (clog) Fail Closed Fail Fail Open (leak) Open Fail Failure Mode Failure Hydraulic Lines Hydraulic Urgent-brake Wire Urgent-brake Urgent Brake Component Urgent Magnet Valve Magnet Auxiliary-brake Shinkansen 200 (Japan) (Japan) 200 Shinkansen 5 of 5 Page Wire Lines Pneumatic 1. If only one car fails. car one only If 1. 2. As long as remaining brakes are functional. are brakes remaining as long As 2. 3 - 1 1 2 C D B2 B2 A2 A2 B3 A2 S Y Y N N N N FS N N N N Y Y Y N Y N FT S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode = S Failure FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No Y = Yes; = Safe; Fail FS Tolerant; FT = Fault Emergency brakes applied brakes Emergency Inspection? cab? in Signal Signal in cab? in Signal (Saturation) cab in Signal performance. train in cab. Change in Signal HowDetected/Response performance. irregular Slightly Signal in cab? in Signal Operator can still apply brakes. Brake brakes. apply still can Operator damage. effected. Friction brakes could be used be could brakes Friction to effected. applied disengaged be be should should Motor brake Emergency train. stop ATC unit activates Emergency brake. Emergency activates brakes unit ATCof deceleration. proper modulation or provide to Blending adjusted brakes. apply still can and Operator Friction between blending brakes of Loss Electrodynamic Effect on Overall Braking System Braking Overall on Effect from wheel/axle to prevent further prevent to wheel/axle from Negligible unless many axles are axles many unless Negligible performance is not effected. not is performance. performance irregular Slightly braking. braking. supplemental for Possible total loss of normal service normal of loss total Possible Table 3-16. Table3-16. ShinkansenF300 M E AWorksheet (resulting in total loss of normal of loss car). total effected in the on brakes (resulting service deceleration. This situation probably situation This all of deceleration. control automatic of Loss Unit Control Command Brake Minor. compensate some to provide near provide to some compensate on braking Electrodynamic of Loss on braking Electrodynamic of Loss available to activate Emergency brake. Emergency activate to available proper provide to error. compensate operator from results should Generator Speed on and based adjust not characteristics would load Adhesion and speed question. in axle question. in axle Effect on Braking Subsystem Braking on Effect ATCunit control. brake of Loss should Generator Speed and Unit brakes. apply normal deceleration. normal both or brakes, friction brakes, Possible loss of Electrodynamic of loss Possible brakes. Operator can still manually still can Operator brakes. slip. wheel Negligible. Brake Command Control Command Brake Negligible. braking level, possibly permitting possibly level, braking signal signal signal failure, Beating Fails to send to Fails to Fails accept/produce charge seizes. axle Fails to send to Fails incorrect Sends process to Fails data signal signal Failure Mode Failure send to Fails Sends incorrect Sends Generator (rotor) Generator Brake Command Unit Brake Control Shinkansen 300 (Japan) (Japan) 300 Shinkansen Component 5 of 1 Page ATCUnit Controller Operator’s Brake Operator’s 3-113 S B2 B3 D B3 D D D C C C N FS N Y N Y Y Y Y Y Y Y FT Y Y Y Y Y Y N N N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode = S Failure FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No Y = Yes; = Safe; Fail FS Tolerant; FT = Fault Indication in cab. Loss of Loss cab. HowDetected/Response in Indication Signal in cab? in Signal Should be unnoticeable unless unnoticeable be significant. Should is error motive power. motive Signal in cab? Inspection? cab? in Signal Inspection? cab? in Signal Inspection? cab? in Signal Signal in cab? Inspection? cab? in Signal brakes Emergency cab. in Signal applied. Signal in cab. Emergency brakes Emergency cab. in Signal applied. Pressure sensor. Emergency sensor. Pressure applied. brakes Effect on Overall Braking System Braking Overall on Effect Friction brakes required to stop train. stop to required brakes Friction Service Emergency Auxiliary brakes on other cars must cars other on brakes must Auxiliary cars compensate. remaining Service on smooth Emergency systems produce to Braking compensate deceleration. Negligible. Other cars will compensate. will cars Other compensate. will Negligible. cars Other Negligible. compensate. will cars Other Negligible. cars. other to applied brakes Emergency Emergency brakes applied on other cars. other be on should applied brakes urgent-braking Emergency of Level Negligible. Other cars will compensate. will cars Other Negligible. If Urgent-brake is applied, Emergency applied, is Service: Emergency Urgent-brake If cars. other relatively unimportant. on relatively applied automatically are brakes Table 3-16. Shinkansen3-16. TableF300 M E A(cont) Effect on Braking Subsystem brake. Braking on Effect dynamic/regenerative on of Loss braking friction auxiliary of Loss car in question. in car Adhesion characteristic improperly characteristic by Adhesion automatically applied brake Urgent Over- or Under-braking on effected on Under-braking or Over- modified car. not characteristic improperly Adhesion characteristic modified Adhesion not characteristic Adhesion for speed. Wheel slip possible. slip Wheel speed. for for load. Wheel slip possible. slip Wheel load. for modified for load. Wheel slip Wheel load. for modified system. of deenergization possible. modified for speed. Wheel slip Wheel speed. for modified Urgent brake over- or under- applied. under- or over- brake Urgent Magnet Valve or pneumatic lines, pneumatic or Valve Magnet possible. May allow damage to Changeover application. to damage allow Urgent-brake May in resulting Fails to accept to Fails process to Fails Failure Mode Failure power generated signal data/send Sends incorrect Sends signal detect to signal Fails speed/send detect to Fails signal/out of signal/out calibration signal/out of incorrect Sends signal/out to calibration Off/Fails Fails signal send load/send signal load/send signal/Out of signal/Out Calibration Sends incorrect Sends regulate to Fails Sends incorrect Sends pressure KlectrO-pneumatic (Power Cabs) (Power KlectrO-pneumatic Component Auxiliary Brake Auxiliary Shinkansen 300 (Japan) (Japan) 300 Shinkansen Catenary 5 of 2 Page (High Pressure) (High Unit Electro-pneumatic Variable Load Variable Magnet Valve (by Changeover Valve Magnet Pattern Generator Pattern Generator Speed Regulating Valve Regulating Speed Signal) Speed Pressure 3-114 D B3 S B3 D C C B3 D D B3 Y FS N Y Y 1 N Y2 N Y Y N Y Y. Y Y N Y FT N Y Y Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode = S Failure FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No Y = Yes; Safe; = Fail FS Tolerant; FT = Fault HowDetected/Response Urgent-brakes and Emergency- situation. apply. Brakes apply. brakes Emergency Pressure sensor. Emergency sensor. Pressure applied. brakes cab. in Signal applied. Inspection. braking. Train cab? in Signal Signal in cab? Minor loss of loss Minor cab? emergency in in Signal performance brake cab. in Signal cab. in Signal sensor Pressure Other cars must compensate. must cars Other None difference. the for compensate Effect on Overall Braking System Braking Overall on Effect and applicable. brakes still Electrodynamic Urgent-brake Negligible. applied. brake Urgent in unaffected. compensate Service: braking must Emergency and Service apply. can Normal car situation. cars Other emergency braking single on to emergency brakes switch should Friction cars Other to train. apply train stop or should allow slow brakes will Emergency system brake significantly Auxiliary None Negligible. Braking on other cars will cars other on Braking Negligible. braking to step train and limit damage limit and train step car. to braking malfunctioning to speed. low at continue to Table 3-16. ShinkansenTable3-16. F300 M E A(cont.) car. Loss of friction braking on effected on braking friction of Loss cab in cab in Indicator On" "Brakes applied. Indicator be Off' cannot "Brakes brakes Friction due to compensation from other cars. other from compensation to due the to applied be cannot Urgent-brake pressure Air check-valve. a longer No Effect on Braking Subsystem Braking on Friction Effect pressure. brake of Loss brakes. to applied. released not brakes pressure No over-braking. Friction or negligible be under- will for effect correct Otherwise, question. in car brakes. friction and Cylinder Effects only one car. It is assumed is It car. one only Effects Relay Valve and Pressure Switch may Switch Pressure and Valve Relay friction of application in Results Booster activate to free reservoir from braking power slightly reduced. slightly power braking brakes. escaping through reservoir. through escaping valving is such to prevent all air from air all prevent to such is valving Fails Closed Fails signal/Out of signal/Out Open Fails Fails to regulate to Fails to Off/Fails Fails signal send Fails On Fails Off FaUs hold to Fails Sends incorrect Sends Calibration Closed Fails Open Fails pressure Failure Mode Failure pressure Air Reservoir Air (Low Pressure) (Low check valve check Pressure Switch Pressure Urgency Brake Urgency Valve Magnet Electro-pneumatic Valve Changeover Shinkansen 300 (Japan) (Japan) 300 Shinkansen Component 5 of 3 Page Relay Valve (with Valve Relay function) Regulating Valve Pressure Regulating 3-115 D S D D C C D C C B3 Y FS Y Y Y Y Y Y Y N FT Y Y Y N N Y N N Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode = S Failure FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No Y = Yes; Safe; = Fail FS Tolerant; FT = Fault HowDetected/Rcsponse Inspection? Inspection? Emergency brakes applied. brakes Emergency Signal in cab. in Signal Signal in cab. in Signal Train brakes in emergency. in brakes Train Signal in cab? in Signal applied. brakes Emergency Signal in cab? in Signal sensor? Pressure compensate for the difference.- the for compensate Effect on Overall Braking System will Braking cars Overall on other on Effect Braking Negligible. ATC automatically applies Emergency None. applies ATCautomatically All normal service braking lost. Train lost. braking. braking service braking. high normal at Emergency All to minimize goes activated and Service: brakes train Emergency slow help Electrodynamic to speed wear. Friction brakes take over at over take brakes train. stop to Friction wear. speeds slower braking. Service: Emergency Electronic no normal both with that will speed braking improbable Service: very Emergency is auxiliary and It service Depending on speed regime, appropriate regime, Service: speed Emergency on with Depending compensate must cars Other None. Train restricted to very low very to restricted Train None. applied. brake systems applied to stop train. stop to applied systems brake braking. increased be lost. Emergency brakes will be will brakes Emergency lost. be ShinkansenF300 M E A(cont) 3 -1 6 . Table Effect on Braking Subsystem Braking on Effect Braking levels are lost since each wire each since lost are levels Braking Reservoir takes longer to fill or does or fill to longer takes car. that Reservoir at power braking decreasing pressure. limit commands an increasing amount of amount increasing an commands brake pressure may be lower, slightly lower, be may pressure brake braking. train. Service stop Normal to of Loss applied brakes Friction not fill to maximum pressure. Applied pressure. maximum to will fill valve not relief Pressure Negligible. Loss of auxiliary friction braking. friction auxiliary of Loss braking effort. braking Emergency braking applied. braking power Emergency brake and pressure air of Loss Auxiliary friction braking limited to limited braking friction Auxiliary one level of brake force. brake of level one in affected car. affected in Fails to supply to Fails One or more (but more or One Failure Mode Failure signal All lines fail lines All cany to Fails pressure too Supplies pressure much signal Both fail to carry to fail Both not all) wires fail wires all) not to fails wire One carry signal carry Fails to carry to Fails signal (leak) Open Fail Component Compressor Air Electrical Shinkansen 300 (Japan) (Japan) 300 Shinkansen 5 of 4 Page Bus (7 wires) (7 Bus Auxiliary-brake Emergency-brake Wiring/Train Data Wiring/Train Pneumatic Lines Pneumatic Urgent-brake Wire Urgent-brake Wires (2 wires) (2 Wires Wire 3-116 B3 S C B3 B3 B3 B3 B3 C B3 C Page 5 of 5 of 5 Page 1)N 1)N 2)Y N N N Y N FS 2)Y N 1)Y 1)Y 2)N3 Y Y Y N Y FT 2)N Y S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode = S Failure FT = Fault Tolerant; FS = Fail Safe; Y = Yes; = N No Y = Yes; Safe; = Fail FS Tolerant; FT = Fault HowDetected/Response Inspection. Inspection. Inspection. Inspection. Pressure sensor? Pressure sensor? Pressure sensor? Pressure Inspection? 1) Other cars must compensate with compensate must cars Other 1) emergency to prevent excessive damage. excessive prevent to compensate. emergency must cars Other damage. excessive many unless compensate will cars Other compensate. increased braking. 2) train brakes in brakes train 2) braking. increased prevent to emergency in brakes Train compensate will cars affected. Other are compensate axles will many Negligible. cars unless Other Negligible. have affected. and are stop to calipers forced reset. be may manually Train should calipers cars Other Negligible. unless many calipers are affected. are calipers many unless .Effect on Overall Braking System Braking Overall on .Effect Table 3-16. ShinkansenTable3-16. F300 M E A(cont.) Loss of friction braking power at power pads. or braking to damage disc cause Mayfriction of disc. Loss effected Brakes 1) cannot be applied or applied be position. cannot applied 1) in Brakes locked affected 2) the at braking friction of Loss axle. excessive caliper. cause may affected disc on Friction Effect on Braking Subsystem Braking on Effect power. brake and pressure of Loss brake pads or calipers. or pads brake Some or complete loss of friction at caliper. of force loss affected braking at complete or Some force friction braking of loss to Total either damage with stress thermal This failure could either 1) prevent in 1) brakes either lock could 2) or failure This application position. brake applied Fails to activate to Fails open) (stuck closed) (stuck Excessive wear. Excessive Fail Closed (clog) Closed Fail calipers Fracture apply to Fail release to Fail Fail Open (leak) Open Fail Fail Closed (clog) Closed Fail Failure Mode Failure Brake discs Brake Booster Cylinder Booster Brake Disc Calipers Shinkansen 300 (Japan) 300 Shinkansen Component Hydraulic Lines Hydraulic Pneumatic Lines Pneumatic lflectm-piieumatic (Power and Trailer ('are) Trailer and (Power lflectm-piieumatic 1. Considered fail safe at lower speeds. Train may derail if brakes are suddenly applied at high speed. high at applied suddenly are brakes if derail may Train speeds. lower at safe fail Considered 1. 2. As long as all cars brake. result. may cars equipment all to as damage long or As 2. fire Since 3. 3-117 3 . 8 E T R 4 5 0 3.8.1 Description of Trainset The Italian ETR450 trainsets have been in revenue service on the main lines of the Italian State Railways (FS) since early in 1990. Derived from the ETR401 passive tilting “Pendolino” trains, the ETR450 trains incorporate an aluminum body and an active tilting system based on accelerometers and gyroscopic sensors that control each car’s hydraulic actuators. The bogie design includes radial steering trucks, flange lubricators, and anti-skid devices. Each bogie is powered by a 312.5 kW traction motor mounted longitudinally on the car body, driving through a U-joint drive shaft, bevel gear final drive and Cardan shafts. Trainset pantographs are carried on bogie-supported frames to allow the cars to tilt up to a maximum allowed eight degrees without interfering with power pickup from the catenary. ETR450 trainsets are currently run in formations of eight powered cars (four sets of “married pairs”) and one trailer car. With each powered car of 50 metric tons and a trailer car of 30 metric tons nominal weight, the total train weighs 430 metric tons (474 tons) with an overall length of 242 meters. The design maximum speed of 250 km/h (155 mph) is realized on the Rome-Florence Direttissima line. On other lines, train speed is limited to a maximum of 200 km/h (125 mph). These other lines include service between Rome-Naples-Salemo, Bologna- Padua-Venice, and Bologna-Milan-Turin. 3.8.2 Braking System Design The ETR450 train braking system includes both air-activated friction brakes and rheostatic (resistive dynamic) braking. Traction motors are used to generate a maximum of 1900 kW braking power at speeds above 80 km/h (50 mph), which is dissipated as heat in resistor banks. A maximum 7800 kW braking power is achieved with both friction and dynamic braking. Disc-type air brakes are used for the friction brake system. Each axle is equipped with two ventilated cast iron brake discs with synthetic brake pads on the brake calipers. Each bogie has four brake cylinders (one per disc) with automatic slack adjustment. The air brake system main line charge/discharge solenoid valves are triggered electrically to speed the brake command propagation along the length of the train. In electrodynamic braking, traction motor armature current is controlled by a shunt-chopper system. Generated power is dissipated in self-ventilated resistor grids on the car body roof. Anti-skid/anti-slip devices are included on each bogie to prevent wheel slip during traction or braking and to optimize wheelset adhesion under adverse rail conditions. 3.8.3 Brake System Perform ance An ETR450 trainset traveling down an 0.8 percent (8 in 1000) grade at an initial speed of 250 km/h (155 mph) can be stopped in approximately 3400 meters, according to the 3-118 manufacturer’s brochure (Ref. 25). No other conditions (dry rail, etc.) are cited for this example. 3.8.4 Braking System Operation, Control and Safety Features Operation and Control ETR450 trainset performance is controlled from an ergonomically designed driver’s cab, which provides instrumentation, control and monitoring equipment in an aircraft-style display. The brake valve includes an electronic device controlling the individual charge/discharge solenoid valves along the train. In the event of an emergency, continuous pneumatic braking control is automatically actuated. Braking systems are blended in five successive stages: the first is fully electrodynamic braking, which is used preferentially to reduce wear on friction brake components and to maintain train speeds, for example, on long downgrades. Subsequent command levels act in conjunction with the friction brakes within the speed range from 250 to 80 km/h. Below 80 km/h, only the friction brakes are active. 3.8.5 Braking System Effects on Vehicle, Guideway, and Infrastructure The ETR450 trainset does not use track brakes such as the electromagnetic or linear eddy v current emergency brake systems used on some high-speed trains. No unusual effects on vehicle, guideway, or infrastructure are anticipated with this type of train design. 3.9 TRANSRAPID TR07 3.9.1 General Description The Transrapid TR07 maglev system is an electromagnetically-levitated transportation system designed for cruising speeds of 400 to 500 km/h (250 to 312 mph). It is being developed by a consortium of German companies with funding from the German Ministry of Research & Technology (BMFT). Testing of various (Transrapid 06/07) system operational aspects has been underway at the Emsland Test Track (TVE) in Germany since 1985. To date, there are no revenue service applications of the system. The TR07 "train" consists of individual cars or vehicle sections, each having a length of 25.5 m, a width of 3.7 m, a height of 3.95 m, and a payload capability of eight metric tons or approximately 100 passengers. Multiple car trains can be configured for bidirectional operation with an operator’s control station at each end. The primary vehicle suspension system is based upon a "wrap around" design in which each vehicle section effectively encloses and captures the T-shaped guideway. Axial flux support magnets, mounted on the vehicle’s undercarriage and powered by DC storage batteries, are oriented to produce the necessary vertical attractive force (to the laminated steel stator packs) for levitating the vehicle. An air gap of approximately 8 mm to 10 mm is maintained between the vehicle and the underside of the guideway. The secondary suspension system consists of pneumatic springs mounted between the coach body and levitation frame. 3-119 Guidance is provided by separate transverse flux electromagnets (also on the vehicle’s undercarriage and powered by the same on-board storage batteries) which produce a lateral attractive force to non-laminated ferromagnetic rails on the side of the guideway structure. Propulsion is provided by a long stator iron core linear synchronous motor, with the three phase windings mounted in a laminated stator under both sides of the guideway structure. The traveling magnetic wave in the stator reacts with the axial flux levitation magnets on the vehicle (acting as the rotor portion of the motor) thereby producing an attractive force for propelling the vehicle. Long stator motor sections (portions of the guideway) are energized as the vehicle approaches a given guideway section and de-energized as the vehicle leaves the section. 3.9.2 Braking System Design The braking strategy of the TR07 is based upon the following key aspects: • Normal dynamic braking via the long stator motor, controlled by wayside equipment. • Emergency braking via an on-board eddy current braking system in conjunction with skids mounted on the vehicle’s undercarriage; the latter involves deactivation of the levitation function; such braking is controlled by on-board equipment; (Note: the long stator motor is the primary emergency braking system if it is operational). • Existence of safe stopping areas (specific locations along the guideway where the vehicle is permitted to come to a stop); this requires maintaining levitation and precisely controlling eddy current braking if guideway power is lost. • Communications via a radio link between safety critical wayside and on-board equipment to determine and/or indicate that emergency braking is needed. Major Braking Components The three major braking components of the TR07 are described below. Linear Synchronous Motor. The linear synchronous motor provides propulsion as well as braking for the TR07. Substations convert 3-phase utility power into variable voltage, variable frequency (WVF) power for the long stator sections in the guideway. Power is fed to the long stator sections via transformers, rectifiers, inverters and feeder cables. In the propulsion mode, the 3-phase AC currents in the long stator sections create an attractive force with the battery-powered levitation magnets on-board the vehicle, thereby essentially pulling the vehicle down the guideway. 3-120 Dynamic braking is accomplished via wayside/central equipment by reversing the polarity of the magnetic fields in the long stator windings. Since, in this mode, the long stator motor acts as a generator, electrical energy is fed back to the substation where it is dissipated in resistor networks. Each long stator motor section on both sides of the guideway is fed from both ends by two pairs of power inverters. This arrangement increases the availability of the propulsion and braking functions carried out by the long stator sections. Eddy Current Brakes. Each vehicle section is equipped with a non-contact eddy current brake system which consists of four brake circuits and two 16-pole longitudinal axial flux magnets (one located on each side of the vehicle). Each longitudinal magnet is divided into four magnet groups, and each brake circuit controls two magnet groups--one on each side of the vehicle. More specifically, each of two choppers within a brake circuit controls one magnet group. The brake circuits in a given vehicle section and their relationship to the brake magnet groups are shown in Figure 3-12. The four brake circuits are powered by separate and independent 440 volt on-board storage batteries. These batteries receive their charging power from on-board linear generators which, in turn, receive their power from the long stator motor in the guideway as long as the long ? stator sections are operational and the vehicle is moving. Charging starts at 60 km/hr and is at full capacity once 120 km/hr is reached. When eddy current braking is deemed necessary (either by the on-board or wayside electronics), the choppers in the brake circuits excite the various magnet groups within the longitudinal magnets on the moving vehicle. This causes magnetic fields in the non-laminated steel guidance rails on the sides of the guideway. The magnetic fields create eddy currents in the steel guidance rail and result in a braking force on the vehicle itself in 4! the direction of travel. A force in the vertical direction on the guidance rail is also generated in this braking process. It impacts the support of the guidance rail itself and is addressed in more detail later. The braking force generated by the eddy currents is dependent upon the air gap, the velocity of the vehicle and the braking current fed to the magnet groups. The braking force in the direction of travel for a given air gap and brake current stays relatively constant from higher speeds down to about 100 to 120 km/h, at which point the force decreases rapidly. Thus, eddy current braking loses its effectiveness as speed decreases below 100 to 120 km/h. This is the reason for the incorporation of brake skids as described in the next section. In emergency braking operations (controlled by on-board equipment), the eddy current brake is used in conjunction with the brake skids to provide the necessary braking. A modification to make the eddy current brakes effective down to 10 km/hr is planned for future revenue service. Brass plates are positioned on the longitudinal magnets to ensure a minimum air gap between the magnets and the guidance rail. During normal operation, no contact occurs between these brass plates and the guidance rail. 3-121 poles of brake magnet grout) 1R Source: Reference No. 3 Figure 3-12. Brake Circuits and Control of Brake M agnets (Ref. 26) 3-122 As discussed above, there are four brake circuits for each vehicle section, giving eight such circuits for a two-section TR07 train (the smallest consist that can be utilized). At least six of the eight brake circuits must be operational for normal travel to be permitted. This matter is discussed in more detail later. Brake Skids. Braking (support) skids, positioned on the lower portions of the vehicle sections (just above the guideway surface), are utilized in emergency braking operations. They come in contact with slightly elevated and parallel gliding surfaces on the guideway structure when levitation is removed during the emergency braking process. Due to irregularities in the guideway surface, the levitation frame of each vehicle section (wrapping around the guideway and providing support for the levitation and guidance magnets) is hinged at several points. There are, in fact, eight hinge points on each side of a vehicle section, making 16 hinge points per section and 32 hinge points for a minimum two-car TR07 train. Each hinge point is equipped with a brake skid (located as described above). Thus, there are 16 brake skids per vehicle section and 32 skids for a two-car train. Each skid, covered with a special material, actually consists of two parallel "bars" (one located on each side of the vehicle), running longitudinally with respect to the direction of travel. Because of the arrangement and mounting of the skids with respect to the levitation frame, and the independent control of the levitation magnets themselves at the various hinge points of the frame, the "touchdown" of each skid is independent from one another. Braking Control Components The portion of the TR07 system that is responsible for the safety, control and supervision of vehicle operations (including braking) is referred to as the Operations Control System (OCS). The system is comprised of on-board, wayside and central elements, each of which performs various train control and braking functions (primarily the former two elements). A simplified functional block diagram of the OCS is provided in Figure 3-13. As can be observed from the figure, the OCS is based on a decentralized philosophy in which each wayside (decentralized) element is assigned to one substation area and is responsible (among other things) for controlling the braking/propulsion of the vehicle in its assigned area or block via the power inverters and long stator motor sections. The primary safety functions including those pertaining to braking are handled by the wayside and on-board elements. The central element (traffic control center) is responsible for the overall supervision and monitoring of system operations. Wayside OCS. The wayside elements assign power inverters to the vehicles and determine the propulsion and braking values required to achieve given speed profiles and/or to comply with specific operating conditions (e.g., position of preceding vehicles, position of switches, occupancy of nearby stations, location of next station). These values are then transmitted to the appropriate guideway long stator sections to control propulsion/braking accordingly. In order to perform these functions, the wayside equipment receives safety critical vehicle 3-123 emergency internal Drake control Figure 3-13. Sim plified Block Diagram of TR07 O CS (Ref. 27) 3-124 location, speed and direction information from the vehicles in its governing area via radio links. It also receives safety critical route integrity information (e.g., location of other vehicles, position of switches) and information regarding status of vehicles in stations from other nearby wayside elements. A given wayside element can initiate dynamic braking via the long stator motor sections or can indicate to a given vehicle that emergency braking must be initiated on-board. The latter requires removal of propulsion power from the guideway. The computer based wayside elements performing these propulsion/braking control functions are often referred to as BLDs. They are implemented with two sets of computers (for availability) arranged in a triple channel computer configuration (for safety). Vehicle OCS. The vehicle portion of the OCS with primary responsibility for controlling the on-board eddy current brakes and levitation magnets (for set-down when landing on the brake skids) is referred to as the vehicle operation control system or BLF. It continuously monitors vehicle location, speed, direction, location of the next safe stopping area and status of certain vehicle equipment, and receives other information from the wayside elements (e.g., status of linear synchronous motor) so as to permit stopping the vehicle at the next safe stopping location independent of the wayside propulsion/braking equipment This is especially necessary in case of loss of communications with the wayside elements. Information regarding the status of certain vehicle equipment (e.g., status of on-board storage batteries or location determination equipment) is transferred to the wayside elements as appropriate via the radio links. This is necessary because certain abnormal conditions of on-board equipment require removal of propulsion power and/or braking via the wayside long stator motor. The on-board BLF equipment is configured in a similar manner as the wayside computer equipment—two sets of computers (for availability), each arranged in a triple channel configuration (for safety). Brake Circuit. The four brake circuits on each vehicle section control the current supplied to the eddy current brakes. As indicated earlier, there are two choppers in each brake circuit, one for each of two 4-pole brake magnet groups. Thus, the four brake circuits on a vehicle section control brake current to the two 16-pole longitudinal eddy current magnets (one on each side of the vehicle). A block diagram of a single brake circuit is shown in Figure 3-14. The normal activation of each brake circuit is controlled by the BLF, and in particular, via the BSE signal shown in Figure 3-14. This signal essentially turns on the brake circuit. Actual braking current for the magnet groups is provided by the choppers, and is a function of vehicle velocity. Vehicles with high velocity require a higher braking current. Current is supplied to the eddy current brakes as appropriate until the set-down speed is reached, at which time the braking current is removed and levitation is deactivated (causing set down on the skids). 3-125 BMG BMG 1R Figure 3-14. Block Diagram of Brake Circuit for Eddy Current Brake System (Ref. 26) 3-126 The BLF can interfere with the braking current by intermittently activating and deactivating the BSE signal. This allows the BLF to bring the vehicle to a more precise stopping location. The brake circuits also have output signals that are used for monitoring the status of the brake circuits. This monitoring takes place via the signals BSR and BSOK (shown in Figure 3-14) which are fed back to the BLF. Two types of monitoring takes place: self monitoring by the brake circuits themselves and monitoring via the BLF. In the first case, the duration of the on-time for each magnet group is monitored. Should excessive time be measured, indicating possible overheating, the BSR signal changes state. In the second case, the BLF sends a command to the brake circuit and looks for a given response in brake current. The proper response is indicated to the BLF via the BSOK signal. The combination of states of the BSR and BSOK signals indicate the status of the brake circuits. This monitoring is important in order to ensure the integrity of the eddy current magnets and brake circuits which allow for the emergency braking of the vehicle should the long stator motor braking be lost. The breakdown of a single brake circuit before a vehicle begins travel or during travel is tolerated. However, should a second brake circuit suffer a breakdown/failure during operation, emergency braking is performed (either via the long stator motor if it is operational or via the remaining eddy current brake circuits). If more than one brake circuit failure is detected before vehicle operation is initiated, travel is prohibited. Signal Safety Device. During the start-up phase of the BLF (vehicle operations control system) and other times in which the BLF is not active, a safety device referred to as the SSW ABI can be utilized under manual control. This device essentially takes the place of the BLF and can enable the eddy current brake circuits and rescind the levitation command at the proper set down speed. It is used only when the BLF is not available for automatic control. When the SSW ABI device is utilized for emergency braking, it can only initiate what is referred to as immediate emergency braking. In this case, maximum emergency braking occurs via the eddy current brakes and skids, and the vehicle comes to a stop (usually not at a safe stopping location). On the other hand, when the BLF is in control, a programmed emergency braking mode is available in which the BLF intermittently controls the eddy current brakes and then the set-down on the skids so as to position the vehicle at the next safe stopping point. Magnetic Regulation Electronics. As discussed earlier, there are a total of 16 hinge points per vehicle section, eight on each side of the vehicle. There are two magnetic regulation electronic (MRE) circuits for each hinge point which control the levitation magnets connected to those hinge points. When levitation is commanded, all MRE circuits are activated. When levitation is to be rescinded, such as during the final stages of emergency braking (when the vehicle lands on the skids), commands must be given to each MRE to rescind levitation at that point. The control to rescind levitation during the emergency braking process is provided primarily by the BLF, but can also be supplied by the SSW ABI safety device. In either case, each MRE only follows the set-down command when vehicle speed is judged to be less than the allowable set-down speed. Thus, each MRE circuit makes its own decision as to whether or not to remove levitation for a given portion of the vehicle. This arrangement makes the 3-127 levitation function extremely reliable which is important given the need to maintain levitation at all times (except during the final stages of emergency braking). Emergency Stop Key Switch. There is an emergency stop key switch on the vehicle console which, when activated, permits the operator to bring the vehicle to an emergency stop. Activating the switch activates the eddy current braking system via the brake circuits, which leads to a rescinding of the levitation command (when the proper set-down speed is reached), and signals the wayside equipment (via the radio link) to remove propulsion from the long stator sections in the guideway. The resulting braking is of the immediate type-the vehicle is stopped at a random location on the guideway. It should be emphasized, however, that levitation is maintained until the proper set-down speed of approximately 120 km/h is reached. For revenue service in Germany, such a stop switch may be modified to only allow stopping at the next "safe stopping area." 3.9.3 Brake System Operation Braking of the TR07 can be categorized into two major types: normal and emergency. These are discussed separately below. Normal Braking Normal (dynamic) Braking of the TR07 takes place via the long stator motor sections, which are under control of the wayside elements. Each wayside control element has propulsion and braking responsibility for a given number of guideway sections or blocks. These blocks may have different lengths, and may have different assigned maximum speeds. There is always a target point (i.e., station or other safe stopping location) associated with the end of each block. The wayside control elements receive information (e.g. speed, location, direction, equipment status) from a vehicle in a given block, and based upon this and other information from adjacent wayside elements (e.g., other vehicle locations/speeds, switch positions, etc.), can automatically reverse the magnetic field in the long stator motor sections and bring the vehicle to a stop. Braking in this manner follows a programmed deceleration curve, and occurs automatically when stopping at designated stations upon requests from the central control element of the OCS and/or when vehicle speed exceeds the maximum safe speed. Emergency Braking Emergency braking occurs under different circumstances (e.g., failure conditions) and is initiated/controlled by either the on-board or wayside elements, depending upon the nature of the condition. This is made possible by the exchange of safety critical information via the radio link between the vehicles and wayside elements. 3-128 Emergency Braking By the Wayside Elements. A wayside OCS element initiates emergency braking under certain circumstances and, when doing so, brings the vehicle to a stop at a safe stopping location through a programmed deceleration curve. In this mode, the on-board element monitors vehicle movement and can supplement the braking process by activating the eddy current brakes and/or skids as appropriate. Examples of conditions that can cause emergency braking via the long stator motor sections are as follows: • Failure of one on-board power supply network (i.e., DC storage battery that acts as a power source for a given eddy current brake circuit) • Failure of two or more of the on-board vehicle location systems • Failure of a "doors closed" signal. Emergency Braking By the On-board Element. The most common emergency braking operation is initiated/controlled by vehicle equipment. Braking of this nature occurs under certain conditions such as the following: • Failure of the radio communication link between the vehicle and a wayside element • Failure of the linear synchronous motor • Violation of the maximum design (safe) speed profile. As indicated earlier, certain information such as the status of the linear motor and location of the next safe stopping point is "continually" transmitted to the vehicle so that decisions can be made by the vehicle OCS (BLF) as to whether to initiate an emergency stop. This information is especially critical, given that in the case of a loss of the communication link 3-; and/or guideway power, on-board equipment must be able to keep the vehicle levitated and bring the vehicle to a stop at a precise location. The emergency braking initiated/controlled by the vehicle equipment is conducted in two phases. Initially, the eddy current brakes are utilized to reduce the vehicle’s velocity to about 120 km/h. Then, the levitation command is rescinded from all magnetic reduction electronic (MRE) units, thereby causing the vehicle to lower on the skids (but only if each MRE unit determines that speed has been sufficiently reduced). The eddy current brakes are switched off after set-down has been accomplished. There is only a brief period of time during which the two braking actions overlap. There are actually two types of emergency braking that can be initiated by the on-board equipment: immediate and programmed. In the immediate mode, the eddy current brakes are activated, followed by the landing on the skids. However, the stop occurs at a random location on the guideway (and not necessarily at a safe stopping point). This is obviously not the most desirable mode of braking, but it does lead to the most rapid stop of the vehicle. It can be controlled automatically by the on-board BLF or manually via the SSW ABI unit as discussed earlier. In either case, the vehicle does not land on the skids until the set-down speed of approximately 120 km/h is reached (as determined by the MRE units). Manual 3-129 triggering of emergency braking via the Emergency Stop Key Switch on the operator’s console also leads to an immediate (as opposed to programmed) braking action. In the programmed emergency braking mode, the most common and desirable emergency braking mode, the vehicle is brought to a stop at the next safe stopping location according to a programmed deceleration curve. Again, the eddy current brakes are utilized to reduce speed to about 120 km/h, at which time the levitation command is rescinded from the MRE units, and the vehicle lands on the skids. The on-board BLF intermittently switches the various brake circuits (of the eddy current brakes) on and off to comply with the programmed braking curve and reach the desired location. 3.9.4 Brake System Perform ance Technical Specifications Practically all detailed information available for this program regarding the characteristics of braking of the TR07 pertains to emergency braking via the eddy current system and skids. In this braking mode, and more specifically, in the programmed emergency braking mode, the braking characteristics follow a deceleration curve stored in the on-board BLF computers. Brake force generated in this mode is dependent upon the current supplied to the brake magnets, the vehicle velocity, and the air gap between the magnets and the guidance rail. The (horizontal) braking force per magnet (for different air gaps) as a function of vehicle speed for a constant brake current of 120 A is shown in Figure 3-15. As can be observed, brake force is relatively constant from higher speeds down to 100-120 km/h, and decreases rapidly below this speed. The actual current supplied to the magnets is provided by the choppers in the brake circuits, under higher control by the BLF computers. This current varies (decreases) as the speed decreases as can be observed in Figure 3-16. The actual deceleration of the vehicle varies with the number of available (operational) brake circuits. As indicated earlier, there are eight brake circuits per two-car train. With all eight operational, tests have shown that deceleration in the 200-400 km/h range is on the order of 1.0 to 1.4 m/s2. Deceleration (under the same conditions) below approximately 200 km/h decreases at a relatively constant rate down to about 0.5 m/s2 at 120 km/h (the set-down speed). Figure 3-17 shows measured deceleration of a two-car TR07 vehicle as a function of velocity for a different number of operational brake circuits. It also shows the planned deceleration curve. After the vehicle lands on the skids and the eddy current brakes are turned off, deceleration ranges from about 0.55 to 0.65 m/s2 until the vehicle is brought to a stop. Figure 3-18 shows a deceleration curve for the TR07 when landing on the braking skids, and with a partial overlap of eddy current braking (with six out of eight brake circuits operational). 3-130 ?. O ] Figure 3-15. Horizontal Brake Force as a Function of Vehicle Speed (Ref. 28) 3-131 i v_ab v_red j I 1 11 1 111 j B e r e i c h AREA. Figure 3-16. Brake Current as a Function of Vehicle Speed 3-132 K e y - 1. 8 out of 8 2 . 7 out of 8 3. 6 out of 8 4. Planned characteristic curve 6 out of 8 (from /l.5/). 5. Special case. Figure 3-17. Deceleration Curves for the TR07 in Eddy Current Braking Mode 3-133 Key 1 - Braking acceleration 2 - Eddy current brake + sliding brake 3 - Sliging braking from /1.8/. 4 - Set-down at 200 km/h. 5 - Braking process 6 - Velocity. Figure 3-18. Deceleration Curve; for TR07 on Braking Skids (Ref. 28) Diagnostics and Monitoring B r a k e Circuits. A s discussed earlier, the m i n i m u m number of brake circuits needed for proper and safe functioning of the eddy current brake system for a two-car train is six (i.e., 6 out of 8). Failure of o n e of the circuits is tolerated either before operation begins or dining actual operation. How e v e r , failure of a second brake circuit during operation results in programmed emergency braking. T he brake circuits are monitored in two ways. First, the current in each of the t w o (4-pole) m a gnet groups controlled b y a single brake circuit is self-monitored by the brake circuit itself. T h e resulting status of each m a g n e t group is fed to the on-board control system (BLF) via the B S O K signal (i.e., one B S O K signal for each of two 4-pole magnet groups). T h e anticipated current of each magnet group is a k n o w n function of vehicle speed, an admissible force of attraction between the magnets and guidance rails, and the status of the B S E control input signal itself (from the BLF). E a c h brake circuit is also put through a periodic functional test in w h i c h each brake circuit is separately activated by the B L F and the response monitored (via the B S R signals) by the BLF. T h e B L F automatically determines the need for emergency braking based upon the statiis of these signals (i.e., B S O K and B S R ) from the various brake circuits. If operation is under control of the S S W A BI, brake circuit status is checked manually. Brake M a g n e t Switch-On Time. Brake magnets for the eddy current system are not designed to be operated continuously. Thus, the switch-on times of the brake magnets are monitored and limited by the BLF. Should a m a x i m u m switch-on time be exceeded, the vehicle is brought to a stop so that maintenance can be performed. Braking Skids. T h e covers on the braking skids are monitored at regular intervals and/or after utilization to ensure the existence of adequate material o n the skids for a future • emergency brake application. Inspection and Test Requirements Available information suggests that all "appropriate means" must be used to ensure the integrity of the eddy current braking system and skids. This includes the performance of certain maintenance procedures at regular intervals (to be determined by the manufacturer and operator based on operational experiences), the inspection of the general condition of the equipment, test of the functional state of parts subject to w e a r (e.g., skid covers, brass sliding plates), and functional tests of the safety and monitoring devices. A maintenance handbook (Reference No. 29), prepared by Thyssen Henschel, suggests various maintenance measures and intervals for the T R 0 7 including components related to the braking system. These measures and intervals are associated with helping to ensure safety, availability and comfort. Various measures are given for inspection/maintenance on a daily, weekly, 14-day, quarterly, semi-annual, annual and "long term" basis. Specific maintenance- related regulations and/or documentation are also cited for the various components. 3-135 Various braking-related components addressed by the handbook include the following: • Levitation magnets, gap monitoring equipment and magnet control unit • Braking electronics and wiring • Brake magnets • On-board storage batteries and other on-board energy supply components • Brake skids • Guide skids • Brake structure • Levitation bogie and secondary suspension. A functional test is r e c o m m e n d e d (by the literature) following the conduct of repairs on the braking components. The handbook also recommends that all maintenance related checks and intervals be adjusted in accordance with operational experience. Braking System Effects on Vehicle, Guideway and Infrastructure There are a n u mber of possible effects on the vehicle and/or guideway associated with braking of the TR07; a few of them are discussed below. Braking Skids/Planes. O n e of the most significant effects of (emergency) braking involves the wear on the brake skid covers due to an emergency brake application. A certain m i n i m u m thickness of the various skid covers must be ensured to permit the proper friction should an emergency brake application be required. It is also possible for the gliding surface on the guideway on which the skids contact during braking to be adversely affected over a period of time. Force o n the Guidance Rail. E d d y current braking results in a braking force on the vehicle in the direction of travel (x direction). However, there is also a force exerted o n the guidance rail in the vertical (y direction) w h e n e d d y current braking is utilized. This force occurs in the air gap between the brake magnet and the guidance rail. T h e important aspect here is that this force increases with a decrease in vehicle speed (during braking) if brake current remains constant. For this reason, brake current m u s t be limited as speed decreases so as to not exceed the m a x i m u m permitted vertical force of approximately 52 k N on the guidance rail and brake magnet support structures. Heating of Brake Magnets. Brake magnets on the vehicle generate heat during eddy current braking. However, as discussed earlier, the switch-on time of the magnets is controlled to limit the a m o u n t of heat generated. Further, it appears f r o m literature that the eddy current brake magnets can withstand full current (without switch-off from the B L F on-board computers) during an immediate m o d e of emergency braking. 3-136 B3 D C C C D S C Y N Y Y Y Y Y FS Y N N N Y Y FT N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT sections. diagnostic. BLF Central control should recognize that recognize should control Central that recognize should control Central sections. effected on and wayside, control, Central section. the in loss power detect Unknown. diagnostic. BLF board equipment detect power loss. power detect equipment board equipment on-board and Wayside How Detected/Response How no braking occurs in the effected the in occurs braking no the in occurs braking premature It is unclear whether the on-board the whether is unclear It signal location last the use computers safe point. safe from the wayside to maneuver train to train maneuver to wayside the from if the or zone station/safety next the immediately. stops train subsequent wayside element. wayside subsequent element. wayside subsequent sections stator long few a or one Only point. safe next at stops on by initiated braking Emergency the in available are resistors Multiple on-board the whether is unclear It computers use the last location signal location last the use computers ifthe or zone station/safety next the Only one or a few long stator sections stator long few a or one Only occur can braking effected. Normal are the of control enters train when sections stator long few a or one Only occur can braking effected. ofthe Normal are control enters .train when braking train effected. Emergency are equipment, on-board by initiated overall on impact minimal networic, Effect on Overall Braking System Braking on Overall Effect braking. to train maneuver to wayside the from immediately. stops train board equipment, train stops at next at stops train equipment, board Table 3-17. Transrapid TR07 FMEA Worksheet signal breaks are tolerable and that if that and tolerable are breaks signal command rescinded once train slows train once rescinded command On-board OCS (BLF) applies (BLF) OCS On-board or static some that is assumed It given a for lost is signal a strong Long stator sections controlled by controlled sections stator Long no provides section stator Long dissipate not do resistors' Effected Current Eddy brakes. emergency energy, reducing braking force. braking reducing energy, to 120 km/hr. to 120 brakes activated and levitation and activated brakes if as respond will train the period, off. failed had link the Braking unexpectedly applied, or no or applied, unexpectedly Braking no provide element wayside the Long stator sections controlled by controlled sections stator Long propulsion or braking force. braking or propulsion propulsion or braking force. braking or propulsion Effect on Braking Subsystem Braking on Effect in minimum), (at occurs propulsion sections. failed the the wayside element continue in a in continue element wayside the propulsive or non-braking mode.1 non-braking or propulsive Fails Interference Off/Loses Contact Signal (braking Oveiheat, bum out bum Loss AC of Loss circuit Open reverses applied) power Fails to Fails sections Prematurely polarity Failure Mode Failure reverse stator long polarity in polarity Elements Long stator section stator Long Vehicle and Vehicle Control Wayside Resistors between Link Radio Transrapid TR07 (Germany) (Germany) TR07 Transrapid of3 1 Page Component element Wayside control Wayside 3-137 B3 S B3 C B3 B3 A3 N FS N Y N N N Y2 FT Y N Y3 Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT How Detected/Rcsponse How computers/BLF On-board On-board computers/BLF On-board Wayside diagnostics train. of diagnostics Wayside diagnostic. (BLF) computer On-board diagnostic. (BLF) computer On-board Preventative maintenance inspections. maintenance Preventative Effect on Overall Braking System Braking Overall on Effect levitation and applied braking Dynamic command rescinded (applied once train once (applied rescinded command be will Train km/hr). to 120 slows safe next to continue to allowed point. stopping Train km/hr). to 120 slows train once Electrodynamic braking applied and applied braking (applied Electrodynamic rescinded command levitation safe next to continue to allowed be will point. stopping fail (unlikely), computers both If Emergency braking must be achieved be must braking Emergency eventual to lead may generator of Loss slows to to 120km/hr. slows communication with the wayside OCS wayside the with communication the lost. trigger be will will with This train the stop to OCS safe wayside next the at braking dynamic point. • stopping wayside-controlled electrodynamic wayside-controlled Emergency braking will be achieved by achieved be will braking Emergency by Electrodynamic braking until train until braking Electrodynamic by Train will skid to a halt although halt a to skid will may Train frame levitation the to damage location of stopping Control result. loss of stored energy in batteries, in energy stored loss of circuit. brake failed a to leading braking. erratic. be may Table 3-17. Transrapid TR07 FMEA (cont.) Effect on Braking Subsystem on Braking Effect At least seven Brake Circuits must Circuits Brake seven least At fail circuits more or two of is total a If braking emergency enroute, while brake. dynamic using applied Loss of some or all Eddy Current Eddy all or of some Loss be operational to permit train to to stait. train permit to operational be by controlled are (Magnets braking. above) circuits 8 brake the Circuit and Eddy Current brake. Current Eddy and Circuit required. be may braking Emergency On-board vehicle control, including control, vehicle On-board No power fed to corresponding to fed power No loss of possible and Battery Storage brake. Current Eddy associated not will item ofthis Failure undercarriage its on skid will Vehicle the to damage possible causing braking, is is lost. braking, Brake corresponding to lost Power immediately or directly affect directly or immediately performance. braking frame. levitation Fail Off Fail Fail Off Fail Failure Mode Failure Fail Off Fail Off/Loss Fail of Power of Fail Off/No Fail Power Output Power Excessive Wear Component Rrafces Current Eddy Brake Circuits (8) Circuits Brake Transrapid TR07 (Germany) (Germany) TR07 Transrapid 2of 3 Page Batteries (8) Batteries Longitudinal Axial Longitudinal Magnets Flux (16 skids per skids (16 440 Volt Storage Volt 440 Generators Linear Landing Skids Landing Vehicle OCS (BLF) OCS Vehicle (2) Computers vehicle) 3-138 c S c D Y Y Y FS N N Y4 FT S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT How Detected/Response How train. of diagnostics Wayside diagnostic. vehicle BLF Wayside diagnostics train. of diagnostics Wayside signal an emergency stop at the next the at stop emergency an signal Effect on Overall Braking System Braking Overall on Effect the at stop emergency "programmed" may BLF the fails MRE one as As soon no is otherwise location. There safe system. braking the on effect electrodynamic braking and eventual and braking electrodynamic Wayside OCS will stop train through train will stop OCS Wayside neutralization of the guideway stator. guideway the of neutralization Wayside OCS brings train to a to train brings OCS Wayside track. the on location safe next Table 3-17. Transrapid TR07 FMEA (cont.) If the switch fails, manual activation manual fails, switch the If BLF is active or the SSW ABI is on. ABI SSW the or is active BLF unavailable. is braking of emergency no or is little there fails, MRE one If Effect on Braking Subsystem Braking on Effect is control train operation, in Once effect. Train cannot leave station until the until station leave cannot Train primarily from wayside OCS. wayside from primarily Fail Off Fail Off Fail Fail Off Fail Failure Mode Failure MREs per (2 MREs Emergency-Stop Switch Key module hinge) module Transrapid TR07 (Germany) (Germany) TR07 Transrapid 3 3 of Page Component Control SSW ABI Manual ABI SSW 1. Wayside control has two sets of computers arranged in a triple channel configuration. channel triple a in arranged of computers sets two has control 1. Wayside 2. If only one circuit fails. fails. no. 2. circuit one Otherwise, only If failure. circuit brake one only in results 3. failure If fails. 4. MRE one only If 3-139 3 . 1 0 H S S T 3.10.1 General Description The High Speed Surface Transport (HSST) maglev system has been under development and through various phases of testing since the 7 0 ’s. Initial designs (i.e., H S S T - 0 1 ) were created by Japan Air Lines (JAL) in 1975. Since then, the system has evolved under leadership of the H S S T Corporation through the HSST-02, -03, -04, and -05. The H S S T - 0 5 was the first two-car train in the series, and was designed for a m a x i m u m speed of 55 km/h. Various evaluation tests have since been conducted at a test track in N a g o y a City, Japan. In 1993, the H S S T Development Corporation was formed to market H S S T technology worldwide, and in particular, the sixth generation system referred to as the H S S T - 100. This system is very similar to the HSST-05, and is designed for a cruising speed of 110 km/h (with a m a x i m u m s p e e d o f 2 0 0 k m / h ) . It should be noted that the braking system description provided herein focuses on the H S S T - 0 5 since most available technical information applies to this version. K e y differences between the H S S T - 0 5 and -100 versions are cited where known. However, it is believed that the basic braking philosophy and key components of the two systems are very similar in n a t u r e . T h e H S S T - 0 5 "train" consists of two cars, each of which has a length, width and height of approximately 18 m, 3 m, and 3.6 m, respectively. Each car can carry about 80 passengers. T h e design is quite similar in s o m e respects to the Transrapid system in that the vehicle wraps around a T-shaped guideway and uses attractive levitation based upon on-board magnets and steel rails in the guideway. O n e major difference, however, is that the H S S T propulsion (and primary braking) system is based u p o n a short stator linear induction motor concept in which the motor primary is on the vehicle and a reaction plate in the guideway acts as the motor secondary or rotor. Electrical p o w e r for propulsion/braking is supplied to the vehicle from the wayside via p o w e r collectors. Primary suspension is provided by the on-board magnets which are used to maintain an air gap of approximately 9 m m (8 m m in the HSST-100). Each vehicle has eight suspension modules (three modules for the HSST-100), which are connected to the vehicle body through a secondary suspension system comprised of air springs (4 springs per module). Each module contains four levitation magnets and one linear motor primary. 3.10.2 Braking System Design T h e braking strategy of the H S S T - 0 5 is based upon the following key aspects: • Dynamic/regenerative braking under normal circumstances via the on-board short stator linear induction motor • A hydraulic/friction braking system to supplement and/or replace dynamic braking, a n d 3-140 Skids on the vehicle for use as a parking brake and, in s o m e instances, for emergency braking in case of loss of levitation. Major Braking Components Linear Induction Motor. The linear induction motor (LIM) is used for normal braking as well as propulsion. In the propulsion mode, three-phase variable voltage, variable frequency ( V W F ) power is provided to the primary side of the motor on-board the vehicle (one L I M per each suspension module). Voltage (i.e. 1500 volts D C ) is transferred to the vehicle via power collectors, located below the suspension modules. T h e magnetic flux generated by the A C current in the primary induces a current flow in the guideway-mounted reaction plates (two steel plates running in parallel with and on the guideway surface). This induced current, resulting magnetic flux and interaction with the primary-generated magnetic flux generates propulsion. In the braking mode, the phase of the A C current in the primary winding on-board the vehicle is reversed, causing an interaction between the magnetic fluxes in the primary and secondary windings, thereby generating a retarding force on the vehicle. P o w e r induced back into the primary winding as a result of the braking action is returned to the wayside via the po w e r collectors. Hydraulic Brakes. Each suspension module on a vehicle (eight modules for an HSST-05) is equipped with a hydraulic brake assembly, consisting of two friction caliper brake units (one on each side of the vehicle). Other associated equipment includes a hydraulic fluid source maintained at approximately 3,000 psi, two hydraulic brake control systems, a hydraulic p u m p control system, and a monitoring/warning system. W h e n braking is commanded, hydraulic fluid is p u m p e d to the brake units, thereby forcing the calipers and brake pads to m a k e -- contact with an extended portion of the guideway structure. A drawing of one hydraulic brake caliper assembly is sh o w n is s h o w n in Figure 3-19. B r a k e Skids. Each module on the vehicle is equipped with two brake skid pads, one on each side of the module. Each pad is located on the bottom of the module and parallel to the vehicle such that the pads m a k e contact with the top of the guideway surface w h e n the vehicle is delevitated. These brake pads are used as a parking brake, but also in the event that additional braking is needed in emergency situations beyond the dynamic and hydraulic friction brakes. Brake Control Components Braking is usually initiated by wayside equipment, but the primary control function occurs within on-board systems. Various control elements are discussed next. Wayside A T P System. Automatic Train Protection (ATP) equipment (some of which is computer based) at various wayside locations receive information from vehicles in its controlling area regarding location and speed. Based upon this and other information such as 3-141 Rail Brake Shoe Hydraulic Brake Assembly Figure 3-19. H S S T Hydraulic Brake Caliper Assembly 3-142 switch status and m o v e m e n t requests from central control, the wayside equipment sends speed and braking c o m m a n d s to a vehicle in a given block. C o m m a n d s are sent to the appropriate vehicle(s) via transponders and vehicle-mounted antenna. On-Board A T P System. Under normal circumstances, on-board A T P equipment receives and interprets speed and braking c o m m a n d s from the wayside, determines the type of braking to be provided (i.e., dynamic, hydraulic friction and/or skids) and determines the appropriate level of braking to be achieved by each brake system. Appropriate control signals are sent from the main A T P control equipment to the various braking control subsystems for further processing. Figure 3-20 shows a general block diagram of die vehicle control system and smaller subsystems. It can be seen from the figure that the major control system in the operator’s compartment interfaces with, a m o n g others, the levitation and brake control subsystems. Brake Control Subsystem. Each module is equipped with a brake control subsystem that receives signals from the main A T P system and interfaces with the W V F inverters and hydraulic braking system. This can be seen in Figure 3-20. In this manner, braking can be performed dynamically via the linear induction motors (LIMs) and/or mechanically via the hydraulic friction brakes. If friction braking is desired, the hydraulic p u m p s are c o m m a n d e d to provide hydraulic fluid to the caliper brake units which, in turn, force the brake shoes' against the guideway. T w o separate hydraulic supply systems are utilized to protect against leaks in o ne or the other hydraulic system. Levitation Control U n i t A s mentioned earlier, brake skids can be used as a means of braking the vehicle under certain circumstances (e.g., loss or ineffective d y n a m i c and friction braking). T h e control of these skids is performed by levitation control units (two for each of the eight vehicle modules) which activate the skids by reducing or removing levitation, thereby causing the skids to m a k e contact with the guideway surface. The amount of levitation is detected b y dedicated sensors. E a c h levitation unit controls t w o of the four magnets on each vehicle module. T h e levitation control unit is under control of the main A T P system in the operator’s compartment. A block diagram showing the configuration of the levitation control components is s h o w n in Figure 3-21. Master Control Lever. There is a Master Control Lever on the operator’s console for the manual control of propulsion as well as braking. This control lever has a position which can be used b y the operator to apply the emergency brakes (i.e., dynamic, friction and/or skids). However, even in the manual position, the A T P system monitors vehicle m o v e m e n t for unsafe conditions (e.g., excessive speed or insufficient braking) and c o m m a n d s braking as appropriate. A T P Disable Switch. T h e A T P disable switch has so m e applicability to braking (i.e., actually relative to releasing the brakes). If a failure occurs in the A T P or other vehicle system, and is detected, braking is initiated via the main A T P and brake control systems. Although the A T P system m a y not permit vehicle movement under these circumstances, activation of the A T P disable switch will allow the operator to release the brakes and m o v e the train to a safe location for passenger unloading. 3-143 orcxATOx** c o w M s a K r W T I I t C I CCMOOCIOCS Figure 3-20. Vehicle Control System and Subsystems 3-144 OCISOOV Figure 3-21. Block Diagram of Levitation Control System 3-145 3.10.3 Brake System Operation Normal Braking Under normal braking situations, the wayside element sends a brake c o m m a n d to the vehicle A T P equipment which initiates and controls braking dynamically via the LIMs. A s discussed earlier, this braking is generated b y reversing the phase of the A C current provided to the LIMs. The braking c o m m a n d is in the form of a deceleration profile. This m o d e of braking is used at speeds higher than eight km/h. B e l o w this speed, dynamic braking is supplemented by the friction brakes. W h e n friction braking is used in a normal braking mode, modulated/controlled brake pressure is provided to the hydraulic systems in only six of the eight modules on a vehicle. Emergency Braking E m e r g e n c y braking is initiated under different circumstances, and can incorporate all three braking m o d e s (i.e., dynamic, friction and skids). If the deceleration profile is not maintained by the dynamic brakes during a normal braking operation, additional braking at emergency rates is provided b y the friction brakes. A n y t i m e the friction brakes are used in an emergency mode, unmodulated pressure is applied to the hydraulic systems in all eight of the vehicle modules (as opposed to only six that are used in normal braking). Should the dynamic brake system fail or the dynamic brake signal be lost, emergency braking is accomplished b y the friction brakes. Emergency braking can also be directed by the wayside or on-board A T P equipment or by the manual application of the emergency position on the Master Control Lever. In these instances, the dynamic and friction brakes are used concurrently. In the event of insufficient emergency braking by the dynamic and friction brakes, levitation will be reduced or removed so that additional braking is provided in a controlled man n e r via the brake skids. This, however, is not a desired condition of operation. 3.10.4 Brake System Performance Technical Specifications Technical specifications for the braking system of the H S S T are limited, but documentation suggests a deceleration capability of 0.07 G for the H S ST-05. Normal and emergency deceleration rates for the next generation H S S T - 1 0 0 A are listed as 2.5 and 3.5 km/h/s, respectively. Diagnostics and Monitoring Although specifics regarding brake system diagnostics and monitoring are not identified in documentation available for this project, it is k n o w n that s o m e monitoring of the brake subsystems does take place. 3-146 Control System Monitoring. It can be seen from Figure 3-20 of this report that a data acquisition system and vehicle system monitor interface with the various vehicle subsystems and the master vehicle system monitor in the operator’s compartment. Annunciations as to certain malfunctions are given in the operator’s console. Further, s o m e of this diagnostic information is inductively transmitted to the central control facility. The main on-board A T P equipment in the operator’s compartment is also monitored. A defect detected in this equipment causes a signal to be fed to the brake control device for the purpose of applying brakes to stop the vehicle. The A T P disable switch can be used to disable the A T P , release the brakes, and m o v e the vehicle to a m o r e convenient location. Brake Performance Monitoring. A s discussed earlier, braking performance is continuously monitored by the A T P system. Should a given braking m o d e (e.g., dynamic, friction) not be providing adequate braking (i.e., actual deceleration not staying within the deceleration profile), additional braking via the friction breaks and/or skids is c o m m a n d e d as necessary to maintain the required braking rate. A s indicated, use of the skids requires delevitation of the v e h i c l e . Inspection and Test Requirements N o specific inspection and test requirements were identified in available literature other than an indication that vehicles are or will be "inspected o n a daily basis prior to their release for operation." It is assumed that this will involve the braking systems to s o m e extent It is also assumed that regular inspections will be needed for various braking system aspects such as the quality/thickness of pads for the hydraulic friction brakes and the brake skids. Portions of the guideway will also need inspection such as the surfaces which interact with the brake shoes and skid pads. Braking System Effects on Vehicles, Guideway and Infrastructure S o m e possible braking-related effects on the H S S T vehicles and/or guideway are discussed b e l o w . Friction Brakes. U s e of the hydraulic friction brakes, which occurs at all times below 8 k m / h and periodically above that speed, will result in wear of the brake shoe pads and s o m e lesser wear on the guideway surface with which they interact. B r a k e Skids. Although it is assumed that the brake skids will be used sparingly for actual braking purposes, such use will result in significant wear on the pads as well as s o m e wear on the guideway surface itself. 3-147 S B3 B3 C D C A2 C N FS N Y Y Y N Y Y FT Y N Y N N N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT On-board diagnostic and diagnostic On-board How Detected/Response How wayside with communication system. ATP On-board ATP in ATP On-board wayside with communication elements. ATP On-board ATP in ATP On-board wayside with communication ATP elements. ATP On-board diagnostics. On-board diagnostics. Wayside and on-board and Wayside diagnostics. in control subsystem Brake system. ATP with conjunction Wayside and on-board and Wayside speed. Friction brakes applied at S km/hr to km/hr S at applied brakes speed. Friction Remaining LIMs available to reduce vehicle reduce to available LIMs Remaining train. stop available. also brakes speed. Friction Effect on Overall Braking System Braking Overall on Effect Remaining LIMs available to reduce vehicle reduce to available LIMs Remaining speed. Friction brakes also available. also brakes speed. Friction Remaining LIMs available to reduce vehicle reduce to available LIMs Remaining Negligible. backup. battery via maintained Levitation emergency for available brakes Hydraulic Vehicle slows due to lack propulsion. of lack to due slows Vehicle application. backup. battery via maintained emergency for Levitation available brakes Hydraulic Train brakes in emergency with dynamic with emergency in brakes Train braking. application. Table 3-18. HSST FMEA Worksheet Effect on Braking Subsystem Braking on Effect dynamic and propulsion of Loss Loss of dynamic braking at effected at braking of dynamic Loss Dynamic braking at effected motors. effected at braking Dynamic braking at affected motor(s). affected at braking ofthe force propulsive the affected, If only some LIMs are effected, the effected, are LIMs some only If motors. If only some LIMs are LIMs some motors. only If for backup battery no (assumes Negligible, if an individual collector. individual ifan Negligible, malfunctioning LIMs may negate the negate may LIMs malfunctioning the negate may LIMs propulsive LIMs. compensate. braking force of the remaining LIMs. remaining ofthe force braking Assume loss of dynamic braking ofloss dynamic Assume Collectors on other modules will modules other on Collectors LIMs using braking No dynamic braking force of the malfunctioning ofthe force braking braking putposes). no putposes). Also braking failed caliper, possibly causing possibly caliper, failed using LIMs. using the at propulsion during brakes Train rail. or pads brake to damage propulsion. Fail Off Fail Failure Mode Failure reverse to Fails Mode) polarity (remains polarity Propulsion in applied) (braking Prematurely polarity reverses off Fails Fails to accept to Fails Fail Off or fail to fail or Off Fail power collect regenerative On Fail power. HSST—High Speed Surface Transport (Japan) (Japan) Transport Surface Speed HSST—High Component of3 1 Page Linear Induction Linear (LIM)(16 Motors Short Stator Short per two-car train) two-car per (16 per train) per (16 Calipers Power Collectors Power Power Wayside Source Hydr«rti<$'r(cttott ftrakos Hydr«rti<$'r(cttott 3-148 S B3 A3 C C B3 B3 c FS N N Y Y N N Y FT Y N N N Y1 Y N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT Inspection. On-board sensors. Levitation How Detected/Response How in ATP On-board wayside with communication elements. ATP diagnostic. subsystem diagnostic. subsystem Braking ATP in communication with communication in ATP elements. ATP wayside On-board sensors. Levitation with communication in ATP elements. ATP wayside On-board sensors. Levitation with communication in ATP elements. ATP wayside Pressure sensors/Braking Pressure Effect on Overall Braking System Braking Overall on Effect either can ATP the enough, decelerating train. set-down to safe train will slow brakes Dynamic for down train set then will speed. ATP skid-braking. stop. available braking friction and dynamic Full available braking friction and dynamic Full track with contact partial makes or down sets to stop train and reduce wear to to skids. wear reduce and train stop to Full dynamic and friction braking available braking friction and dynamic Full Trinset is traveling at or below km/hr 8 below or at is traveling service. Trinset normal in used brakes friction when is not train the that senses ATP the If or calipers remaining to pressure increase backup. for exists None. controller A second low very at used only are normally Skids noticeable. be not may complete to speeds. Effects train train bring can brakes Hydraulic to skids. wear reduce and train stop to Train to skids. wear reduce and train stop to , in order to stop. to , order in Table 3-18. HSST FMEA Worksheet (coni.) Less stopping power, possible power, stopping Less Effect on Braking Subsystem Braking on Effect remaining units to lower train. lower to units remaining (overbrakes). early down None. On-board ATP signals ATP None. On-board to set tries train of portion Effected prevent complete loss. complete prevent None. undercarriage. to damage ATP contact. make may skids Other in set-down to train command will Train underbrakes. calipers Other underbrakes. Train Wayside ATP may also neutralize also may ATP Wayside . puipose. same for track Possible loss of friction braking. loss of friction Possible to available systems supply Two emergency. must compensate. must Fail Off Fail Fails Off Fails (assumed Off Fail Incorrectly Fails Hold to Fails wear Excessive that fault circuit 2 or 1 effects Magnets Signals Delevitate to Fail Off Fail Pressure/Fluid magnets)2 Failure Mode Failure Control Units (2 Units Control HSST—High Speed Surface Transport (Japan) (Japan) Transport Surface Speed HSST—High 2 of3 Page Levitation (2) Levitation 2 controlling levitation Brake Skids (2 Skids Brake per (4 Magnets Component (2) per module, each module, per magnets) Hydraulic Brake Hydraulic System Control Hydraulic System Supply Calipers module) per module) per 3 - 1 4 9 D S A3 C C C C C Y FS N Y Y Y Y Y Y FT N N N N N N S = Failure Mode Severity, described in Section 2.2 Section in described Severity, Mode Failure = S FT = Fault Tolerant; FS = Fail Safe; Y = Yes; N = No = N Yes; = Y Safe; Fail = FS Tolerant; Fault = FT How Detected/Response How Levitation sensors. sensors. On-board Levitation with communication in ATP wayside ATP elements. ATP wayside Wayside elements? Wayside diagnostics? On-board On-board and wayside and On-board Diagnostic ATP and On-board diagnostic On-board and ATP Diagnostic On-board and wayside and On-board known. Not Effect on Overall Braking System Braking Overall on Effect stop to available brake speeds. Hydraulic Train is expected to be traveling at very low very at traveling be to is expected Train train. by compensate may Train increasing/decreasing dynamic and/or friction and/or dynamic increasing/decreasing effort. braking has train Once braking. friction and levitation offdynamic turn can ATP wayside stopped, Train goes into emergency braking with braking emergency into goes Train train stop to used systems braking Available otherwise be unaffected. be otherwise based on wayside instructions. wayside on based train. stop to used systems braking Available immobile. be will Train power to lower train. lower to power Wayside or on-board ATP will control will ATP on-board or Wayside will Brakes emergencies. in some brakes Table 3-18. HSST FMEA Worksheet (cont) Effected portion of train fails set to fails oftrain portion Effected slow/too fast and adjust accordingly. adjust and fast slow/too On-board computers determine will computers On-board Effect on Braking Subsystem Braking on Effect (underbrakes). expected when down Skids will wear excessively if the excessively will wear Skids that train is slowing down too down is slowing train that contact. make to continues train ATP switches to emergency braking. emergency to switches ATP On-board ATP commands emergency commands ATP On-board braking of the train. the of braking manual in train put cannot Operator braking of the train. the of braking brakes. release not Will will remain train mode. rest, at If brakes of control immobile. Manual lost. Wayside ATP commands emergency commands ATP Wayside Levitation Incorrectly Failure Mode Failure Incorrectly Magnets Signals Measures Air Measures Gap to Maintain to Fail Off Fail Fails Off Fails Off Fails Off Fails Fails Off Fails HSST—High Speed Surface Transport (Japan) (Japan) Transport Surface Speed HSST—High Component Levitation (2. Units Control 3 3 of Page controlling 2 controlling Levitation levitation ATP Disable ATP per module, each module, per per (2 Sensors module) Automatic Train Automatic Automatic Train Automatic magnets) Lever On-board Wayside Protection (ATP) Protection (ATP) Protection Switch Control Master ■OetfecaJ 1. System will tolerate loss of one supply system. supply one of loss tolerate will 1. System 2. Assumed that a simultaneous failure of all levitation magnets is very unlikely due to back-up systems. back-up to due unlikely is very magnets levitation all of failure simultaneous a that 2. Assumed 3 - 1 5 0 3.11 MLU-002N 3.11.1 General Description The MLU002N is a Japanese maglev system that is under development and is based upon electrodynamic levitation using superconducting magnets. It is the latest in a series of maglev systems being developed by the Railway Technical Research Institute (RTRI) and funded by the Japanese Ministry of Transport. Original development work for the system was initiated by the Japanese National Railways, but was taken over by the RTRI in 1987. The predecessor to the MLU002N was the MLU002, which was destroyed by fire in 1991. Speeds of up to 394 km/h were achieved with the MLU002 vehicle at the Miyazaki Test Track before the fire. Testing has been underway since January 1993 at Miyazaki test track using the MLU002N vehicle in order to assess the economical and technical feasibility of a 500 km/h commercial maglev system. Revenue service operation of the train is not expected to occur until about the year 2005. The MLU002N is a single-bodied vehicle that is designed to travel in both directions. Its total weight is about 20 tons and has a total length, width and height of 22 m, 3 m, and 3.7 m, respectively. It is expected that future trainsets will consist of 3-car or 5-car units with a car containing the operator’s control station on each end and passenger cars in the middle. Up to four different lightweight bodies have been developed for these applications using different materials and construction techniques. The MLU002N vehicle, which rides in a u-shaped guideway, incorporates repelling superconducting magnets (on the lower sides of the vehicle) which interact with electromagnets on the guideway walls to provide levitation, guidance, propulsion and electric braking. Propulsion as well as braking is provided through the use of a long stator linear synchronous motor. One unique characteristic of this electrodynamic system is that it incorporates wheels beneath the vehicle on which the vehicle rides until adequate levitation is achieved—since proper levitation does not occur via the superconducting magnets until an adequate vehicle speed is attained (which induces the proper magnetic forces). Thus, primary suspension of the vehicle is maintained by the wheels (at lower speeds) and the levitation system at higher speeds. A secondary suspension system based upon the use of air springs is also incorporated. 3.11.2 Braking System Design The braking system design of the MLU002N is based upon the use of electrical and mechanical brakes as well as an aerodynamic brake. These brakes are used under different conditions and in different speed ranges. The specific braking strategy as anticipated for the vehicle is shown in Table 3-19. It should be noted that the braking systems, and especially the disc brake system, are under development and have not been finalized. Additional details of these developments are discussed in later sections. 3-151 Table 3-19. Braking Strategy of the MLU002N Brake System Usage Speed Range Regenerative Brake (Electric) Normal Braking 0-500 km/h Emergency Braking Dynamic Brake (Electric) Failure of Regenerative Brake 0-500 km/h Failure of Substation Landing Skid Brake Failure of Electric Brakes 0-350 km/h (Mechanical) Disk Brake (Mechanical) Failure of Electric Brakes 0-500 km/h Aerodynamic Brake Failure of Electric Brakes 200-500 km/h Major Braking Components Linear Synchronous Motor (Electric Brake). The primary mode of braking, for the MLU002N is electric in nature and is provided by the long stator linear synchronous motor (LSM). In a propulsion mode, three-phase current is fed to the guideway-mounted electromagnets which react with the on-board superconducting magnets to produce a propulsive force. A traveling wave in the guideway propels the vehicle via both attractive and repulsive magnetic forces. The guideway-mounted electromagnets act as the armature of the motor, while the superconducting magnets act as the rotor. Electric braking is actually of two types: regenerative and dynamic. In regenerative braking, which is the type most often used, the phase of the current in the guideway coils is reversed, thereby inducing a brake force on the vehicle. Electrical power generated by this form of braking is returned to the substation for other usage. Dynamic braking is provided in essentially the same manner, but the generated power is dissipated in a resistor network on the wayside. This mode is used if, for some reason, electrical power cannot be returned to the substation. Disk Brake. Considerable attention is being directed by the designers of the MLU002N to a disk brake system that could be used as a backup should there be a failure of the electric brake. One problem has been that the downward force on the bogie wheels decreases as vehicle speed increases and levitation force increases because the wheel assemblies are raised and lowered as levitation force increases and decreases. This has resulted in a lower available braking force by the wheel disk brakes at higher speeds. Another problem has involved the development of a disk brake system that could be effective over the entire speed range of 0 to 500 km/h (and especially the higher speeds due to increased temperature generated during braking). At the present time, should electric braking not be available, the disk brake system is utilized at lower speeds and the aerodynamic brake at higher speeds (above 200 km/h or so). 3-152 Although details of the current disk brake system are not clearly identified in available literature, it is believed that the system is very similar (if not identical) to a newly developed disk brake system that is described in documentation. It is this system that is described below. It should be noted that documentation indicates this new disk brake system has been successfully tested up to speeds of 500 km/h (Ref. 30). The lower levitation forces at the new test track have resulted in sufficient train weight on the bogie wheels at higher speeds to permit sufficient braking force (via the wheel disks) at the higher speeds. Each bogie of the MLU002N is equipped with four wheel assemblies, one on each comer below the bogie frame. Each assembly is comprised of the following major components: • Support arm—Mechanical arm for raising and lowering the wheels and axle, based upon applied levitation force; the arm is gradually raised as vehicle speed increases • Wheel/axle assembly—Axle with two wheels that is attached to the support arm • Rubber tires—Two rubber tires which make contact with the guideway surface • Tire pressure monitor (TPIS)—Sensor for monitoring tire pressure • Wheel speed sensor—Sensor for measuring speed of the wheel/axle assembly; used for brake control • Disk brake assembly—Disk brake unit mounted on each wheel • Auxiliary wheel—Additional wheel on the wheel/axle assembly that can support a comer of the bogie should the tire(s) become deflated. A diagram of the disk brake system for a single bogie is shown in Figure 3-22. When braking is commanded by an electronic control unit (ECU), the hydraulic system furnishes fluid at the proper pressure to all disk brakes on the vehicle bogie (two disk brakes for each of the four wheel assemblies) to generate the required braking force. Aerodynamic Brake. The MLU002N is fitted with two sets of aerodynamic brake devices (Ref. 31). Each set consists of two panels mounted on the vehicle top, about 5 m from the end of the vehicle. The panels (in this test vehicle) are oriented in the same direction so that braking via these panels is accomplished as the vehicle travels in only one direction. The principle of the devices is based upon the proportional relationship between air resistance (for braking) and the front face area of the vehicle and its speed. Under normal operation (no braking) the panels are closed and flush with the vehicle’s surface. Should emergency braking be needed (electric brake not operable), the panels are opened to create increased air resistance. The panels are opened to about 45 degrees with the aid of a spring, after which the air resistance itself pulls the panels open even further until they are essentially perpendicular with the vehicle body. The effectiveness of the panels is greatest at higher 3-153 LVv\»vmvwAWAm!! Figure 3-22. Disk Brake System for MLU002N 3-154 speeds and decreases rapidly below about 200 km/h. This is why, at the present time, a combination of aerodynamic and friction braking (via the wheel assemblies) is used for emergency braking purposes. Major components of the aerodynamic brake system and their functions are as follows: • Brake panels—Two sets of slightly curved panels (curved in the direction of vehicle travel) which provide air resistance when activated (opened); each has a surface area of about 1.95 m2 • Stay dampers-Two dampers on each panel to perform four functions: 1) absorb the shock of the spring force when the panel is first opened, 2) absorb air pressure impact just before the panel is fully open, 3) provide viscous damping to control the opening speed, and 4) act as a "stopper" when the panel is fully open; (currently, panels must be closed manually after use). • Unit box—A special compartment on the top of the vehicle in which the panels and dampers are located; it seals out water from the vehicle interior • Locking device-A mechanical locking device (comprised of a hook, springs, magnets and other items) on each panel to keep the panel in the closed position when braking is not desired, and allow opening of the panel when braking is desired. Figures 3-23 and 3-24 show several different views of the aerodynamic brake and opened panels on the MLU002N vehicle, respectively. Landing Skids. Each bogie is equipped with four landing skids, two mounted underneath and on each end of the bogie. The bottom of the skids are fitted with metal shoes which can be commanded to come in contact with the guideway surface at lower speeds, when the wheel assembly is retracted, and when levitation is removed. Figure 3-25 shows the location of the skids on the new double bogie frame for the MLU002N. Indications are that the skids could be used for braking (if desired) at vehicle speeds below 350 km/h. However, should electric braking be lost, it is more desirable to use the wheel disk brakes in combination with the aerodynamic brake. Brake Control Components Operational Safety System. The operational safety system for the MLU002N is comprised of both wayside and on-board control elements as can be observed in Figure 3-26. One major element on the wayside that is highly involved in brake control is the safety control system which has the following responsibilities: • Generate maximum speed, route and brake commands (including emergency brake commands) to the wayside running control system (portion of the equipment responsible for sending propulsion and brake commands to the guideway mounted 3-155 1674 iue32. SeveralViews Aerodynamicof 3-23.Figure Brakes DN ID T C F S fi-B 3-156 W E I V C - C Figure 3-24. Opened Aerodynamic Brake Panels INTERMEDIATE BOGIE FRAME AIR-SPRING CONNECTING TO THE BODY AIR-SPRING FOR ELASTIC SUPPORTING OF SCM SCM SUPPORTING FRAME Figure 3-25. Double Bogie Frame With Landing Skids 3-158 Soot: conditions ------> Operation control systec Percissible speed. Safety control location systec <------— ^ 7 \ 7 \ Running speed Speed Unit Indication Indication Stop target Energency stop locz: ior. Control prohibition Indication of devices condition Running Location control systec i switching of Stitching signal information (Po*er converter) (Route control) Running speed (Brake control) Indication Location rrequency information Current Stitching instruction Conversion. Lock . Feeder line. Stitch. Coil Brake Train running, stoppage control selling stock Figure 3-26. Operational Safety System 3-159 linear synchronous motor coils); electric braking of the vehicle (either regeneratively or dynamically) is controlled in this manner • Generate and transmit brake control signal commands to the train itself; these signals form the high level control for the disk brakes, aerodynamic brakes and landing skids. Thus, the safety control system generates safe commanded speeds, detects overspeed conditions and controls propulsion and braking systems both on and off the vehicle. Disk Brake Control System. This on-board system, referred to as the anti-skid, auto-brake control system (ACS), controls application of the disk brakes on the wheel assemblies. It is comprised of an electronic control unit (ECU) and a hydraulic control valve module (HCM). These components and their interface with the wheel assemblies and disk brakes can be observed in Figure 3-22 (earlier in this report). The primary purpose of the ACS is to stop the vehicle within the designated deceleration profile while preventing wheel (tire) skid. The ECU monitors wheel speed of the various wheel assemblies and commands the HCM to apply the appropriate hydraulic pressure to increase and or decrease braking force on a given wheel. Other functions of the system are to eliminate tire burst (by releasing pressure when skid is detected), to eliminate torque unbalance between the different wheel assemblies, and apply a parking brake when the vehicle is at rest. Aerodynamic Brake Control Circuits. Four control circuits are used to control the aerodynamic brakes, one circuit for each brake panel. A diagram of the control circuit arrangement is shown in Figure 3-27. Each control circuit involves two magnet holders and two switches. When power is applied to the magnet holders, the brake panels are closed and locked. When power is removed via a command from the control system, the lock is released and the panels begin opening via a spring-assisted stay damper that helps absorb the shock of opening the panels and serves as a stopper when the panels are fully open. With no wind, the panels open to an angle of about 45 degrees with the vehicle roof. Wind resistance will pull the panels fully open shortly after the initial release. As mentioned earlier, the stay damper controls the opening speed. Panels must be manually closed after use by pulling the stay damper to the closed position. Landing Skid Control. Although details of the control aspects for the landing skids were not identified in available literature, it is assumed that the landing skids (and therefore the bogie) can be lowered in a controlled fashion to provide braking if so desired. However, it is also assumed that this is not a desirable braking mode, except for a parking brake. 3.11.3 Brake System Operation Braking of the MLU002N can be categorized into two major modes: normal and emergency, These are discussed next. 3-160 DC2 4 V±15% (0.3 8A± 10%) DC 2 4 V±1S% (0.36A±1 0%) sg-rfc.r—V. • 'll• 11 ”li « . 4 W ' » L ! ! 11 11 1 " ______... ; . 4 j ' J a . ------« . 4 W i i s . _____ ...... ______.._...... h..i.k.t.x;.ii.._...— — •— ------• ___ :-: j - ;■ \ ------______•— '.'.a.3I— I i ------______I_ J T i ii • i ______L-.:_J-4-i! ! I rtSit ^ . v u i w______. » ______. • .____j.j..i ___ _T, . 1 W U ______■ - - - — a i i DC2 4 V±15% (0.38A±1 0«) DC2 Figure 3-27. Control Circuits for Aerodynamic Brakes 3-161 Normal Braking Normal service braking of the vehicle is provided electrically in either a regenerative or dynamic manner via the linear synchronous motor. Regenerative braking in which power is returned to the substation is used when possible, otherwise dynamic braking is utilized. Emergency Braking Should an emergency situation arise and electric braking be unavailable, emergency braking can be accomplished either regeneratively or dynamically via the linear synchronous motor. However, should electric braking not be available, emergency braking can be accomplished in different ways dependent upon the speed of the vehicle. If the vehicle is traveling at high speeds, aerodynamic brakes are used to reduce the speed to a point (about 200 km/h) at which the disk brakes would be more effective. The disk brakes could then be used to bring the vehicle to a stop. It should be noted that, as discussed earlier, the disk brake (and levitation) systems are being developed so that disk brakes could be used up to 500 km/h in emergency situations. Another possibility for emergency braking involves the landing skids. These skids (and actually the bogies on which the skids are mounted) could be lowered such that the skid shoes come into contact with the guideway surface. According to literature, considerable developments are underway in the braking system for the MLU002N, and the braking components/strategy is still in a state of change. 3.11.4 Brake System Performance Technical Specifications Although no quantitative data on the electric braking system were identified in available literature, some general information regarding deceleration rates was found on the aerodynamic and disk brake systems. Aerodynamic Brakes. As described earlier, each aerodynamic brake panel (of which there are four on the MLU002N) has a projected area for braking of approximately 1.95 m2, giving a total available braking area of 3.9 m2 for one set of panels. The deceleration provided by one set of panels for an 18.5 ton vehicle traveling at 420 km/h is approximately 0.15 g. Deceleration with both sets of brake panels opened is slightly higher, but the braking force provided by the second (rear) set is lower than the front set due to turbulence created by the front panels. Tests confirmed that, although deceleration levels were lower, abnormal vehicle movement is not adversely affected with the utilization of only one of the two brake panels. Disk Brakes. Dynamometer tests have been conducted on the new disk brake system under development. Actual deceleration was measured under different simulated conditions (e.g., 3-162 emergency stopping, anti-skid), and the values ranged from approximately 0.2 g to 0.6 g. The maximum deceleration that could be achieved by the disk brakes at a (wheel) drum speed of 550 km/h was 0.6 g. Normal expected levels of deceleration are expected to be in the range of 0.2 g. Diagnostics and Monitoring Very limited information is available on the diagnostic and monitoring capabilities utilized in the MLU002N. However, it is known that the Central Control Unit on the wayside is the primary control and supervisory element of the system. This system does have the capability to monitor the deceleration profile, determine when electric braking is not available, and command on-board braking via the aerodynamic, disk and/or landing skid systems. Switches are incorporated within the aerodynamic brake system to detect when each panel is closed and opened. There are several known diagnostic/monitoring systems associated with the (disk) Brake Control System or ACS (as noted earlier) and its Electronic Control Unit (ECU). Wheel speed relative to the disk brake wheels is measured by an optical type sensor, which is: replacing an inductive device. Tire pressure as well as tire skid and wheel lock are measured for each of the wheel assemblies. Low pressure or other detected problem results in removal of the brake pressure applied to a given wheel assembly. Each wheel assembly is also monitored for torque unbalance in which case brake pressure is adjusted accordingly. Inspection and Test Requirements Again, there is very limited information here, but it is assumed that regular tests and inspections will be necessary to assure the integrity and proper operation of both the electric and backup braking systems (i.e., aerodynamic, disk and landing skids). Periodic inspections will certainly be needed of the tires, wheels, and disk brake and landing skid pads as well as the guideway surface with which the wheel assemblies and landing skid pads interact A brief operating test has been developed for the aerodynamic brakes. It involves the manual control of power to permit the inspection of the opening motion of the panels. As noted earlier, the system is currently designed such that the panels must be closed manually. An inspection port has been incorporated into the aerodynamic brake panel compartment (unit box) to allow a routine inspection of the brake panels from within the vehicle. Braking System Effects on Vehicle, Guideway and Infrastructure Several possible effects on the vehicle and/or guideway as a result of braking are discussed below. Disk Brakes. The disk brake pads, wheels and tires will experience wear with usage. A minimum thickness of material must be ensured on the pads to permit the proper friction 3-163 should emergency braking be necessary. It is also possible for the guideway surface with which the tires interact to experience some wear. Landing Skids. Landing skid pads and the associated portions of the guideway surface will experience some wear if the landing skids are used for braking purposes. Again, a minimum thickness of material will be needed on the pads. Guideway Integrity. Usage of superconducting magnets for propulsion, levitation and (electric) braking generates a strong force on the vehicle as well as on the coils mounted in the guideway walls. This requires the coils in the guideway walls to be installed accurately and with consideration of the expected forces (including vibrations) to be experienced. Also, the superconducting magnets and high speeds of the vehicle generate eddy currents and other magnetic forces in nearby conductive materials. Therefore, the guideway must be designed to minimize interaction with such magnetic fields. 3-164 4 3 3 B D D C D S C A C of 1 N Y Y Y N Y Y FS Y N Y Y Y N Y N N FT S = Failure M o d e Severity, described in Section 2.2 Section in Mdescribed o=S dFailure eSeverity, F T = Fault Tolerant; FS = Fail Safe; Y N=Yes; Safe; =No FS =Fail Tolerant; F T=Fault Assume on-board control control on-board Assume Assume on-board control control on-board Assume control wayside Assume Unknown. on-board Assume (TPIS). monitor Tire pressure Unknown. TPIStire. may detect of skidding overpressure How Detected/Response indication. control wayside Assume indication. control on-board Assume indication. indication. indication. . indication. . control Dynamic and aerodynamic brakes available available brakes aerodynamic and Dynamic overheat. could tire skidding If uncorrected, Other braking systems available. available. systems braking Other high at brakes disc and Aerodynamic lower speeds. at skids landing plus speeds, available. systems braking Other high at brakes disc and Aerodynamic speeds. lower at skids landing plus speeds, in unaffected usable brakes Dynamic sections. resistive using brake dynamic except None, for mode none. Normally, Principal in addition to remaining disc brakes. disc to remaining in addition available brakes aerodynamic and Dynamic Other braking systems available. available. systems braking Other high at brakes disc and Aerodynamic speeds. lower at skids landing plus speeds, mode. Important is regenerative. brake dynamic case in that fails; mode only if regenerative available. also modes braking other available brakes aerodynamic and Dynamic Effect on Effect on Overall Braking System in addition to remaining disc brakes to stop to stop brakes disc remaining to in addition train. in addition to remaining disc brakes. disc remaining to in addition MLU002NFM EWorksheet A 3-20. Table Ineffective disc braking at one one at braking disc Ineffective structure. supports No effect. No effect. braking Dynamic mode. resistive to switches available not are resistors Effected Guideway section provides no provides section Guideway One comer of bogie no will of bogie have comer One brake. Will disc on down likely set for braking. be sufficient should set. wheel Auxiliary wheel is ovetbraked, set wheel Effected No dynamic braking (assumes no (assumes braking No dynamic reducing energy, dissipate to Effect Effect on Braking Subsystem in failed braking No dynamic Propulsive sections. guideway landing skid. Other three discs discs skid. landing three Other of skidding causing potentially tires. rubber battery backup for braking braking for backup battery Also purposes). no propulsive resistive in the power braking mode. force may remain. force braking or dynamic propulsive force. power. Fails ro lower lower ro Fails or deflated Burst by indicating Fails speed wheel Fails to accept accept to Fails Fails to reverse reverse to Fails wheel assembly wheel high incorrect Fails off Fails power regenerative bum out Overheat, guideway circuit Open Failure Mode in polarity (4 N— Linear Motor Car Maglev (Japan) Page 002 Electronic Control Control Electronic Unit (ECU) Rubber tires Rubber MLU Resistors Arm Support source per bogie) per Wheel Assembly Assembly Wheel Long stator section Long stator Component Disc BrakeDisc Wayside power power Wayside Wayside control control Wayside element 3-165 3 4 3 S D A D C C D B of 2 Y FS N Y Y Y Y N Y FT N N N Y N Y S = Failure Mo d e Severity, described in Section 2.2 Section in described Mo =S dFailure eSeverity, F T = Fault Tolerant; FS = Fail Safe; YN Yes;= =NoSafe; FS =Fail Tolerant; F TFault = How Detected/Response Unknown. on-board Assume Unknown. in braking Change control indication. control control indication. control Unknown. Unknown. TPIStire. may detect of skidding overpressure force likely to be noticeable to to noticeable be to likely force operator. train Unknown. Assume on-board Unknown. on-board Assume Unknown. TPIS Assume and attempt ECUwould indication, Unknown. TPIS Assume and attempt ECUwould indication, to compensate. to compensate. to HCM/ECU indication. Effect on on Effect Overall Braking System Also, dynamic affected. set inwheel Only one available brakes aerodynamic and available. brakes aerodynamic and Dynamic addition to remaining disc brakes. brakes. Change disc remaining to addition minimal. be should distance in stopping If unconected, skidding tire could overheat. overheat. could tire skidding If unconected, available brakes aerodynamic and Dynamic in available brakes aerodynamic and brakes. Change disc remaining to addition in addition to remaining disc brakes to stop to stop brakes disc remaining to in addition train. Also, effected. dynamic set Onlywheel one minimal. be should distance in stopping overheat. could tire skidding Ifuncorrected, available brakes aerodynamic and Dynamic to stop brakes disc remaining to in addition Also, dynamic effected. set in Onlywheel one available brakes aerodynamic and brakes. Change disc remaining to addition train. minimal. be should distance in stopping available brakes aerodynamic and Dynamic in addition to' remaining disc brakes to stop to stop brakes disc remaining to' in addition train. MLU002NFM E AWorksheet(cont) 3-20. Table Table Effect Effect on Braking Subsystem underbraked. is set wheel Affected No braking or braking command command braking or No braking Affected wheel set is overbraked, is overbraked, set wheel Affected underbraked. is set wheel Affected for disc brakes. for disc Affected wheel set is underbraked. is set wheel Affected potentially causing skidding of skidding causing potentially tires. rubber is overbraked, set wheel Affected tires. rubber Disc braking lost for the affected affected the for lost Disc braking potentially causing skidding of skidding causing potentially bogie. bogie. of disc half Would one be brakes for a two-car train. two-car for a brakes Fails by indicating by indicating Fails Failure Mode low incorrect speed wheel ECU off fails Fails by indicating by indicating Fails Fails by providing by providing Fails wheel speed wheel speed wheel by providing Fails Leaks, fails to to fails Leaks, incorrect high high incorrect by indicating Fails low incorrect much too pressure hydraulic too little hydraulic hydraulic little too pressure maintain pressure maintain N— Linear Motor Car Maglev (Japan) Page 002 MLU Component Control Electronic Unit (ECU) Hydraulic Control Control Hydraulic (HCM)Module Hydraulic System System Hydraulic single (assume bogie) per system Wheel Speed Speed Wheel Sensor 3-166 4 3 3 3 3 B C B S B C A of 3 N N Y Y N FS N Y N Y N N Y FT .1 S = Failure Mo d e Severity, described in Section 2.2 Section in Modescribed =S dFailure e Severity, F T = Fault Tolerant; FS = Fail Safe; Y N=Yes; =Safe; No FS =Fail Tolerant; F T=Fault Associated panel control control panel Associated Associated panel control control panel Associated position. panel indicates circuit control panel Associated control panel Associated position. panel indicates circuit Unknown. How Detected/Response control panel Associated position. panel indicates circuit position. panel indicates circuit circuit indicates panel panel indicates circuit position Dynamic and disc brakes available to stop to stop available brakes disc and Dynamic to stop must train assume manually; stowed panel. stow be must brake. to to Panel Train begins stop must train assume manually; stowed panel. stow to stop available brakes disc and Dynamic Effect on Effect on Overall Braking System to stop available brakes disc and Dynamic train. be must brake. to Panel Train begins to stop available brakes disc and Dynamic train. train. train. MLU002NFM E(conL) AWorksheet 3-20. Table Table Brake panel deployed when no when deployed panel Brake reduction. If rear panel, less less panel, Ifreduction. rear deployed. no when deployed panel Brake deployed. Possible brake panel damage or loss loss or damage panel brake Possible Reduced deployment. on force. braking If front aerodynamic deployed. are Reduced aerodynamic braking braking aerodynamic Reduced significant force. panel, Iffront are panels if front important is requested. braking less panel, Ifreduction. rear are panels if front important deployed. Effect on on Effect Braking Subsystem braking is is requested. braking reduction. If rear significant panel, panels if front important less panel, Reduced aerodynamic braking braking aerodynamic Reduced significant force. panel, Iffront force. If front panel, significant significant force. panel, If front less panel, Ifreduction. rear are panels if front important Reduced aerodynamic braking braking aerodynamic Reduced Activates panel panel Activates damp to Fails forces opening Fails to unlock to Fails Unlocks activate to Fails prematurely prematurely panel Failure Mode deploy to Fails / (4 (4 N— Linear Motor Car Maglev (Japan) Page 002 Brake panel stay stay panel Brake panel) (per damper (each panel) (each Brake panel panel Brake MLU control circuit control Brake panel panel Brake device locking Component Brake panel panel Brake panels per car) per panels 3-167 4 3 S A C c C of 4 FS N Y Y Y FT N N N N S = Failure M o d e Severity, described in Section 2.2 Section in described M o=S dFailure eSeverity, F T = Fault Tolerant; FS = Fail Safe; Y NYes;= =NoSafe; FS =Fail Tolerant; F T =Fault How Detected/Response Inspection. On-board indication. On-board OSS. to Indication On-board indication. On-board (cont.) Effect on on OverallEffect Braking System brakes disc and aerodynamic, Dynamic, available to stop train. Disc brake can stop stop train. can brake Disc to stop available of on control under systems All braking train at low speed. at train of control under systems All braking (OSS). System Safety Operational wayside of on control under systems All braking board system. board board system. board MLU002NFM EWorksheet A 3-20. Table Effect Effect on Braking Subsystem and power braking Reduced Brake control reverts to on-board to on-board reverts control Brake system. possible damage to undercarriage. to damage possible Brake control reverts to wayside wayside to reverts control Brake system. to on-board reverts control Brake system. Excessive wear Excessive Fails to command command to Fails Failure Mode required Fails to command command to Fails off Fails braking when when braking braking when when braking required N— Linear Motor Car Maglev (Japan) Page 002 MLU Brake Brake Control Component Skid Pads Skid Safety Operational On-board Brake Brake On-board Control Wayside Control Communications Communications link between link between On and Wayside Control board . Indication appears to be separate from activation. from separate be to appears . Indication 1 3-168 APPENDIX A - BIBLIOGRAPHY General References 1. Kenneth G. Ellsworth, Ed., The Car and Locomotive Cyclopedia of American Practices, Simmons-Boardman, Fifth Edition, 1984. 2. D.F. Russell and A.J. Williams, “The Design and Development of a Brake Disc for High-Speed Trains,” Proc Instn Mech Engrs Vol 204, Part F: Journal of Rail and Rapid Transit, 1990, pp 133-139. 3. H.G.P. Burt and E. Saumweber, “Microprocessor Control of Wheel Slip,” 1985 IEEE/ASME Joint Railroad Conference, Pittsburg. 4. G. Gagarin, U. Kroger, and E. Saumweber, “Eddy-Current Magnetic Track Brakes for High Speed Trains,” 1987 IEEE/ASME Joint Railroad Conference, Toronto. 5. P. Lohmeier, “Advanced Braking Technology for High Speed Trains,” Proc Int Conf on Speedup Technology for Railway and Maglev Vehicles, Yokohama, Japan, Nov 1993, Vol 2, Paper C4-l-(2), pp 213-217. 6. Laplaiche, M., Freinage des trains a grandes vitesses, Collogue ore "Grand Vitesses," 1971. AMTRAK Metroliner—Northeast Corridor Service (USA) 1. Max Ephraim, Jr., “The AEM-7 - A New High Speed, Light Weight Electric Passenger Locomotive,” ASME Paper 82-RT-7, April 1982. 2. K.G. Ellsworth, Ed., “The Car and Locomotive Cyclopedia of American Practices,” 1984 edition, Simmons-Boardman. 3. Telephone conversation with Mr. Ed Lombardi, Engineer of Tests, Amtrak. ICE—InterCity Express (Germany) 1. T. Rahn, “Development of new high-speed motor train units to be operated on the German Federal Railway network,” Proc Instn Mech Engrs Vol 202, IMechE 1988, pp 125-137. 2. Klaus Becker-Lindhorst, “The ICE brake equipment,” ICE High-tech on Rails, Hestra Vertag (1990), pp 80-85. A -l 3. Anon., “ICE Braking System Strategy,” Knorr-Bremse AG Miinchen, January ’91. 4. Anon., “Questions and Answers on the ICE-Brake System,” Knorr-Bremse AG in response to visit by U.S. DOT/FRA delegation, Feb. 27, 1991. 5. Anon., “Safety Relevant Observations on the ICE High Speed Train,” DOT/FRA, July 1991. 6. T. Rahn and H.R. Kurz, “The Intercity Express - high-tech on rails,” Railway Tech. Review Special, Eurail ’92, pp 3-13. 7. A. Tayler, Hi-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. 8. C. Taylor, “Speed Survey — TGV heads Nozomi, as AVE speeds from behind,” Railway Gazette International October 1993, pp 675-680. 9. Knorr-Bremse AG, “Brakes: Abridged Description for ICE/USA,” Ref: TA 19691/43 (from Siemens Transportation Systems, Inc.), 14 May 1993. TGV Atlantique— Trains a Grande Vitesse (France) 1. H. Rollet, “The TGV Rolling Stbck-Its Evolution and Capabilities,” GEC Alsthom - Transportation Projects, Publ. No. AH-REB-06 (no date). 2. M. Boiteux and B. Christians, “Brake gear on future Atlantic TGV trainsets,” Revue Generate des Chemins de Fer (RGCF), Sept. 1987. 3. D.F. Russel and A.J. Williams, “The design and development of a brake disc for high speed trains,” Proc Instn Mech Engrs Vol 204, IMechE 1990, pp 133-139. 4. Anon., “Safety Relevant Observations on the TGV High Speed Train,” DOT/FRA, July 1991. 5. White Paper, “Braking System of the ’Train a Grande Vitesse’,” GEC Alsthom/Bombardier, Jan. 8, 1992 [proprietary]. 6. A. Tayler, Hi-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. X2000 Tilting Train (Sweden) 1. Anon., “Brake system, Project: X2000US,” ABB Traction Dok. No. 6141 033, Oct. 26, 1993. A-2 2. B.M. McLaughlin, “Brake System Overview for the USA High Speed Rail Demo Trains (X2000, ICE),” The Air Brake Association Annual Technical Conference, Chicago, Illinois, September 12-15, 1993. 3. S.P. Caliciotti, S.A. Costanzo, and G. Gagarin, “Demonstration of the X-2000 on Amtrak,” Amtrak document (1993, no specific date given). 4. M. Knochenhauer, “X2 — Safety Analysis of Brake System,” ABB Traction Inc. memo, Aug. 28, 1992. 5. R. Nilsson, “X2000 U.S. Demonstration Project — Summary of Test Results,” ABB Traction Inc. memo dated Sept. 21, 1993. 6. Anon., “Safety Relevant Observations on the X2000 Tilting Train,” DOT/FRA, March 1991. 7. L. O’Conner, “Tilting Train Smooths Out The Curves,” Mechanical Engineering, Feb 1993, pp 62-65. 8. A. Tayler, H i-T e c h Trains, Quinset Publishing Ltd., 1992, pp 10-21. 9. C. Taylor, “ Speed Survey — T G V heads Nozom i, as A V E speeds from behind,” Railway Gazette International October 1993, pp 675-680. 10. M . Fermier, “Brake discs for passenger trains - a theoretical and experimental comparison of temperatures and stresses in solid and ventilated discs,” Proc Instn Mech Engrs Vol 206, Part F: Journal of Rail and Rapid Transit, 1992, pp 37-46. Intercity 125 & 225 (Great Britain) 1. A . Tayler, Hi-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. 2. R. Barnett, “Working Paper 563: British Rail’s Intercity 125 and 225,” Institute o f Urban and Regional Development, University of California at Berkeley, June 1992. 3. O.S. Nock, “Two Miles a Minute: The Story Behind the Conception and Operation of Britain’s High Speed and Advanced Passenger Trains,” Foreword by Sir Peter Parker. Cambridge: P. Stephens (2nd Ed.), 1983. 4. Additional technical documentation supplied by British Rail. Shinkansen 200 and 300 (Japan) 1. A . Tayler, H i-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. A-3 2. C. Taylor, “ Speed Survey — T G V heads N ozom i, as A V E speeds from behind,” Railway Gazette International October 1993, pp 675-680. 3. Japanese Railway Information, “Railway Systems and Components,” No. 8, December 1980. 4. Japanese Railway Information, “Railway Systems and Components,” No. 54, October 1992. 5. P. Lohmeier, “Advanced Braking Technology for High Speed Trains,” Proc. InL Conf. on Speedup Technology for Railway and Maglev Vehicles, Nov. 22-26, 1993, Yokohama, Japan, Vol. 2, Paper C 4-l-(2), pp 213-217. ETR450 (Italy) 1. A . Tayler, Hi-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. 2. Fiat Ferroviaria, “The Future of Rail Transport is Already Way Down the Line,” manufacturer’s brochure, no date given. Transrapid TR07 (Germany) 1. Dorer, R.M and Hathaway, W .T., "Safety of High-Speed Magnetic Levitation Transportation Systems-Preliminary Safety Review of the Transrapid Maglev System," DOT/FRA/ ORD-90/09, U.S. Department of Transportation, Volpe National Transportation Systems Center, November 1990. 2. Heinrich, Dr.-Ing K. and Kretzschmar, Dipl.-Ing R., "Transrapid Maglev System," Hestra-Verlag Darmstadt, Circa 1988. 3. "Assessment of the Through Brake Concept (Eddy Current Brake) for the TR07," Report No. 947/B 88/146, Tiiv Rheinland, Germany, 7/26/1988. 4. "Eddy Current Brake System for the TR07 Vehicle," Technical Report, Document No. AS 900314 168, Thyssen Henschel, Circa 1989. 5. "Expert Comments on the Eddy Current Brake System of the TR07 Overall Function of the Emergency/Secondary Brakes," Document No. ZG 900911 - 0216, Tiiv Rheinland, 8/25/1990. 6. "Demands on the Eddy Current Brake (Non-Contact Through Brake) for Magnetic Levitation Vehicle TR07," Document No. ZS 900314 165, Tiiv Rheinland, 8/1/88. A-4 7. Henneberger, Dr.-Eng. G, "Final Report-Calculation of Braking and Acceleration Forces of the TR07 Eddy Current Brake," Institute for Electrical Machines, Aachen, Germany, 5/18/90. 8. Letter and enclosures on acceptance testing of the Signal Safety Device (SSW ABI) in the original process certification of the eddy current brake ("WSB") system, (Document No. GA 900314 0177), Tuv Rheinland, 3/13/90. 9. "Short Review of the Braking Philosophies of Transrapid," Tiiv Rheinland, 9/6/90. 10. "Determination of Intervals Between Stopping Places," Control No. 900918-0219, Thyssen Henschel, 8/6/90. 11. "Initial Commissioning of Support/Guidance System TR07 at the Emsland Test Facility," Document No. NTA/1486/05/90, 5/14/90. 12. "Maintenance Handbook-TR07 Vehicle Interval Planning," Document No. WR 930128-0331, Thyssen Henschel, December 1992. 13. Benedickt, C., Kunsel, T. and Stichel, S., "Technical Readiness Transrapid Magnetic High-Speed Railway Safety of Transrapid System," Institute for Bahntechnik, 9/7/90. 14. Luedeke, J., "Evaluation of Concepts for Safe Speed Enforcement," Final Report, Battelle, April 3, 1992. 15. A Comparison of U.S. and Foreign Safety Regulations for Potential Application to Maglev Systems, DOT/FRA, Volpe National Transportation Systems Center, October 1992. HSST— High Speed Surface Transport (Japan) 1. "Technical Description," HSST Corporation, August 1989. 2. Hashimoto, Fumio, "Signalling System of Maglevtype HSST," Railway Signal Division, Kyosan Electric Mfg. Company, Limited, Yokohama, Japan, Circa 1991. 3. "HSST-100A Specifications," HSST Development Corporation, June 11, 1993. 4. "HSST-100A Test Plan," HSST Development Corporation, June 11, 1993. 5. "HSST Development History," Source and Date Unknown. 6. "Urban Transport Type Magnetic Levitation Linear Motor Car Commercialization Research Study—An Overview of the Study Findings," Source and Date Unknown. A-5 7. Gordon, Jeff, "Trip Report-Meeting with M TI and HSST Development Corporation," U.S. Department of Transportation, Research and Special Programs Administration, June 21, 1993. 8. Luedeke, J., "Evaluation of Safe Speed Enforcement Concepts," Final Report, Battelle, April 3, 1992. MLU002N—Linear Motor Car Maglev (Japan) 1. Sasaki, T. and Tsuruga, H., "Vehicles for Superconductive Maglev System on Yamanashi Test Track," Railway Technical Research Institute (RTRI) and Central Japan Railway, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 2. Yoshimura, M. and Okamoto, H., "Development of Aerodynamic Brake System for MLU002N on Miyazaki Test Track," RTRI, Kawasaki Industries, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 3. Takizawa, H. and Hamada, K., "The Development of Disk Brake System for Maglev Train," RTRI, Sumitomo Precision Products, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 4. Igarashi, M ., Oshima, H., Sakamoto, H. and Takakura, T., "Carbon-Carbon Composite Brake System for Maglev Trains," Central Japan Railway, Sumitomo Metal Industries, Sumikin Design and Engineering Company, Ltd., Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 5. Ozeki, M ., "Current Status of Research and Development of Superconducting Maglev System in Japan," RTRI, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 6. Igarashi, M., Oshima, H., Sakamoto, H., Qi, K., and Salamat, B., "Digital Brake Control System for Maglev Trains," Central Japan Railway, Sumitomo Metal Industries, Sumitomo Metal Technology Inc., and Crane Co. Hydro-Aire Div., Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 7. "Linear Motor Car-Maglev," RTRI, Japan, circa 1993. A-6 REFERENCES 1. Kenneth G. Ellsworth, Ed., The Car and Locomotive Cyclopedia of American Practices, Simmons-Boardman, Fifth Edition, 1984. 2. Laplaiche, M ., Freinage des trains a grandes vitesses, Collogue ore "Grand Vitesses," 1971. 3. H.G.P. Burt and E. Saumweber, “Microprocessor Control of Wheel Slip,” 1985 IEEE/ASME Joint Railroad Conference, Pittsburg. 4. G. Gagarin, U. Kroger, and E. Saumweber, “Eddy-Current Magnetic Track Brakes for High Speed Trains,” 1987 IEEE/ASME Joint Railroad Conference, Toronto. 5. Max Ephraim, Jr., “The AEM-7 - A New High Speed, Light Weight Electric Passenger Locomotive,” ASME Paper 82-RT-7, April 1982. 6. Anon., “Brake system, Project: X2000US,” ABB Traction Dok. No. 6141 033, Oct. 26, 1993. 7. B.M. McLaughlin, “Brake System Overview for the USA High Speed Rail Demo Trains (X2000, ICE),” The Air Brake Association Annual Technical Conference, Chicago, Illinois, September 12-15, 1993. 8. S.P. Caliciotti, S.A. Costanzo, and G. Gagarin, “Demonstration of the X-2000 on Amtrak,” Amtrak document (1993, no specific date given). 9. M . Knochenhauer, “X2 — Safety Analysis of Brake System,” ABB Traction Inc. memo, Aug. 28, 1992. 10. R. Nilsson, “X2000 U.S. Demonstration Project — Summary of Test Results,” ABB Traction Inc. memo dated Sept. 21, 1993. 11. Anon., “Safety Relevant Observations on the X2000 Tilting Train,” DOT/FRA, March 1991. 12. Klaus Becker-Lindhorst, “The ICE brake equipment,” ICE High-tech on Rails, Hestra Vertag (1990), pp 80-85. 13. Anon., “ICE Braking System Strategy,” Knoir-Bremse AG Miinchen, January ’91. 14. T. Rahn and H.R. Kurz, “The InterCity Express - high-tech on rails,” Railway Tech. Review Special, Eurail ’92, pp 3-13. R -l 15. Anon., “Safety Relevant Observations on the ICE High Speed Train,” DOT/FRA, July 1991. 16. Knorr-Bremse AG, “Brakes: Abridged Description for ICE/USA,” Ref: TA 19691/43 (from Siemens Transportation Systems, Inc.), 14 May 1993. 17. H. Rollet, “The TGV Rolling Stock-Its Evolution and Capabilities,” GEC Alsthom - Transportation Projects, Publ. No. AH-REB-06 (no date). 18. M . Boiteux and B. Christians, “Brake gear on future Atlantic TGV trainsets,” Revue Generale des Chemins de Fer (RGCF), Sept. 1987. 19. D.F. Russel and A.J. Williams, “The design and development of a brake disc for high speed trains,” Proc Listn Mech Engrs Vol 204, IMechE 1990, pp 133-139. 20. Anon., “Safety Relevant Observations on the TGV High Speed Train,” DOT/FRA, July 1991. 21. White Paper, “Braking System of the ’Train a Grande Vitesse’,” GEC Alsthom/Bombardier, Jan. 8, 1992 [proprietary]. 22. A. Tayler, Hi-Tech Trains, Quinset Publishing Ltd., 1992, pp 10-21. 23. Japanese Railway Information, “Railway Systems and Components,” No. 8, December 1980. 24. Japanese Railway Information, “Railway Systems and Components,” No. 54, October 1992. 25. Fiat Ferroviaria, “The Future of Rail Transport is Already Way Down the Line,” manufacturer’s brochure, no date given. 26. "Assessment of the Through Brake Concept (Eddy Current Brake) for the TR07," Report No. 947/B 88/146, Tiiv Rheinland, Germany, 7/26/1988. 27. Luedeke, J., "Evaluation of Concepts for Safe Speed Enforcement," Final Report, Battelle, April 3, 1992. 28. "Expert Comments on the Eddy Current Brake System of the TR07 Overall Function of the Emergency/Secondary Brakes," Document No. ZG 900911 - 0216, Tiiv Rheinland, 8/25/1990. 29. "Maintenance Handbook-TR07 Vehicle Interval Planning," Document No. WR 930128-0331, Thyssen Henschel, December 1992. R-2 30. Takizawa, H. and Hamada, K., "The Development of Disk Brake System for Maglev Train," RTRI, Sumitomo Precision Products, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. 31. Yoshimura, M . and Okamoto, H., "Development of Aerodynamic Brake System for MLU002N on Miyazaki Test Track," RTRI, Kawasaki Industries, Japan, Proceedings of the International Conference on Speedup Technology for Railway and Maglev Vehicles, Yokohama, November 22-26, 1993. R -3/R -4