65 New Developments in Railcar Trucks
WILLLU1 W. DICKHART III
ABSTRACT
In this paper the results of the develop ment of the ASDP truck for heavy rail tran sit applications are discussed. The ASDP truck has a truck-frame-hung monomotor and a very soft secondary air suspension. Also, DloC a number of options that have been devel BRA.KE oped for the basic Budd P-III railcar truck, of which some 10,000 have been built for transit, commuter, and main-line ser MOTOR A.'5'5'{ vice, are discussed. The modifications or 1'2.00 options that have been developed include a soft primary suspension, a steerable truck, a simplified secondary suspension, and a tilt truck for high-speed corridor operation.
In this paper the results of the development of the ASDP truck for heavy rail transit applications are discussed. Also discussed are a number of options that have been developed for the basic Budd P-III railcar truck.
ASDP TRUCK
The ASDP truck (Figure 1) is a monomotor truck wi tt. a very soft secondary suspension that was developed FIGURE 1 Monomotor truck. under an UMTA subcontract. The monomotor gearbox assembly is supported from the truck frame, thereby reducing the unsprung weight. The primary suspension uses a chevron-style rubber sandwich design in an tain, three-piece truck. Approximately 10,000 trucks outside bearing configuration. Two primary suspen have been built for transit, commuter, and main-line sion spring rate sandwiches were used to investigate service, even for the super-speed linear induction the effect on wayside vibration during tests. The motor research vehicle (LIMRV) , which established secondary suspension is very soft around the operat the world's speed record of 256 mph in 1972. The ing height: however, the rate increa\.es with travel P-III truck has a stiff primary suspension with a from the mean position, which prevents overshoot. spring rate of approximately 150,000 lb/in. The development of the ASDP truck, including In general, the secondary suspension is soft ver static and fatigue tests, has been documented (1:_) • tically and laterally. A number of options have been Subsequently, one car set of trucks was fabricated, developed recently for this basic P-III truck. These applied to one of the state-of-the-art cars (SOACs) , options retain the basic softer primary suspension and tested by the Budd Company at Pueblo, Colorado, or steering. under an UMTA contract. The ride data (Figure 2) indicated reduced vertical accelerations compared with the standard truck, as was forecasted in the SOFT PRIMARY TRUCK computer simulations. Wayside data (Figure 3) also revealed the reduction in accelerations with the Data from the ASDP test and computer results from softer 60, 000 lb/in. primary springs compared with the Budd Company vehicle dynamics and right-of-way the 180, 000 lb/in. primary springs, as was fore interaction simulations have indicated that small casted by the Budd wayside/vehicle interaction com reductions in primary spring rate can result in puter simulation. This truck could be equipped with large reductions in both rail forces and truck frame a Simotrac propulsion package. accelerations. One modification developed for the P-III truck is the soft primary P-III truck. The journal end of the truck frame has been redesigned P-III TRUCK (Figures 6 and 7) to accommodate a horseshoe-shaped elastomeric sandwich, which results in primary The P-III truck (Figures 4 and 5) was developed by spring rates of approximately 25, 000 lb/in. verti the Budd Company more than 25 years ago. It was the cally and 60,000 lb/in. longitudinally. This ar first application of air springs for railcar trucks. rangement provides controlled longitudinal motion of The P-III truck features a direct load path from the the wheels and can allow some steering in large car body through the air springs to the bolster and radii curves. Prototype trucks were tested in a side bearers to the truck frame and wheels. The bol joint program with the National Passenger Railroad ster rests on the twin side frames, which also serve Corporation (Amtrak). Measurements of a train pass as equalizers. The result is a simple, easy-to-main- ing at 100 mph verified that the wayside accelera- 66 Transportation Research Record 953
-- ASOP TRAILlllG HARO PRIMARY .... --- SOAC TRAILING ~ 60 MPH <.:> STATION 6 10 OF UMTA TEST LOOP WELDED RAIL WOODEN TIES i.ll SO AC..,A EFFECTIVE BAND WIDTH • .16Z Ha. ~ >- I\ t: II VJ 11 Z .01 LlJ ~ 0 (\ 1'I __J I I
10 15 20 FREQUENCY- Hz FIGURE 2 Comparison of ASDP to SOAC midcar vertical acceleration levels.
40 MPH HARD PRIMARY I- 0 . 2. s t't:-1
40 MPH SOFT PRIMARY
60 MPH HARO PRIMARY
,0 MPH SOFT PRIMARY
70 MPH HARD PRIMARY
70 MPH SOFT PRIMARY
7G NP H HARO PR IMARY
76 M P ll SOFT PRIMARY
LEAD AXLE OF '0.7 FT FROM OUTSIDE RAIL TRAILING TRUCK WELDED RAIL CONCRETE TIES PASSING WAYSIDE SCALE = 0.1 G/IN LOCATION PAPER SPEED= 5 IN/SEC DATA FILTERED AT 5 0 H.,, FIGURE 3 Effect of primaries on ASDP wayside vibrations, ASDP trailing truck data.
tions were indeed reduced by the softer primary sus A powered truck version of the soft primary was pension (Figure 8) • developed for the self-propelled M-1 Long Island Data from the road tests with instrumented cars - . . . Railroad (LIRR) cars. Initial tests also indicated Cl.JIU, Ll.Ul.:~::i ..LJlU..L\..:ct i... ~ ct Lt:=UUC..:LJ.VII J.Il Ll.Ul.:I'\. l.Ldlll~ a<.,;- that the accelerations of the frame were signifi celerations with the softer primary, as was also cantly reduced. This car has been in revenue service forecasted (Figure 9). Currently, the prototype trucks have accumulated more than 350, 000 miles in for more than 1.5 years and has accumulated approxi the several years of revenue service. This design mately 100,000 miles, with essentially no flange is now the standard truck f or the Amfleet II cars. wear. Dickhart 67
SHOCK SO:CONDARY TRUCK l.BSOR BER AIR SP'11t!G EOLSTER
BODY ANC HOR BRAKE THI RD RAIL SIGNAL PRll.iARY ROD ASSEMBLY COLLECTOR PICK OP 1iPAING FIGURE 4 PATCO P-III truck (side).
THIRD RAil lRuCI\ BOLSTER ------...'....J .W .~~~~~~~~~~~~-~COLLECTOR
SICiNAI.. PICK OP
TRUCK SIDE FRAME RICHT SIDE
1.10TOR ANO CEAA BOX
MOTOR •NO GEAR BOX ' \
I ,,' -1--·, I TRUCK StDE •I ---< ~r - - -r '1- t-..:::::=::_,.~- F'RAl. FIGURE 5 PATCO P-III truck (plan). SOFT BUSHING TRUCK Corporation (PATCO) for more than a year. The verti cal spring rate is 70,000 lb/in. and the longitudi Another modification reduces the primary stiffness nal rate is 40,000 lb/in. The modification has both vertically and longitudinally without modifying resulted in reduced wheel wear, especially on the the truck frame. This is accomplished by substitut face of the flange (Figure 10) when compared with ing a sculpted bonded bushing in place of the con the married car with the standard bushing (Figure ventional hard primary bushing. The soft bushing 11). modification, as it is called, had been tested in a This same principle has also been applied to the cooperative effort with the Port Authority Transit trucks on Washington Metro, alth~ugh the trucks were 68 TRUCK FRAME crn6"'TIJTllj!'[ I FIGURE 7 Primary suspension and journal assembly. FIGURE 6 Soft primary. l_ 10 I l I l I §_J 1§1 1U 1li AXLE AXLE AXLE AXLE zli._D 21i.P 21i.P 2 t.!P zl:!il AXLE AXLE AXLE AXLE AXLE Dickhart 69 SOf"T fRIMAl'.1' .-,. ::· ... · . : A~lf... a_.~··1.•1\\\l'tfl.l ~""'.._J~,1:,\,.._·~-J.-.~'•. .;,-~::;<'.l',\.- . ., --r----..--...... CAR.A SllFF PRIMARY ....,j .. \/ ' '~_/\./' CAR 9 SOFi PR.IMAP-.'1' -~ ...... ~~-- ·-:.. ~'"~.,,--.--~::..::.;,,,.--. • ..:--. -~· .-~ "TltU 16,358 MILES 9-17·82 33,896 MILES 2·1·83 CN PROFILE BUDD SOFT BUSHING JOURNAL SUSPENSION CAR NO. 284 SCALE 2X FIGURE 10 Wheel profile wear-soft bushing. 16,358 MILES 9-17-82 33,886 MILES 2·1·83 AAR 1: 20 PROFILE STD. PID JOURNAL RUBBER CAR NO . 283 SCALE 2X FIGURE 11 Wheel profile wear-standard car. not produced by the Budd Company. In tests sponsored be parallel, which results in wheel wear, rail wear, by UMTA Cll , Budd soft bushings tested on Washington and noise in sharp curves. Allowing longitudinal Metropolitan Area Transit Authority (WMATA) trucks compliance in the primary suspension, as in the soft reduced the lateral track forces in curves up to 75 primary of soft bushing truck, alleviates this con percent (Figure 12). The soft bushings have been in dition somewhat . However, only with a steerable revenue service at WMATA for more than 12 months truck can the axles assume a radial position with with about 60,000 miles. One of the significant dif respect to the truck in the tight curves. ferences between the standard bushings and the re The steerable truck, by reducing the angle of at placement is lack of settlement (Figure 13). In the tack between the wheel and the rail, eliminates the past year the settlement of the standard bushings on noise and reduces track and 'wheel wear. A steerable the married car has been continuing and is close to the condemning limit. version (Figure 14) of the P-III truck has been de veloped and extensively tested over the past few years. This program was a joint effort of UMTA, STEERABLE TRUCK PATCO, and Budd. To accommodate tight curves, the axles, motors, and brakes are mounted on arms (Fig In conventional trucks the axles are constrained to ure 15) that steer beneath the main truck frame 70 Transportation Research Record 953 - ' I ,I ', I I I \. STIFF, CYLIND~ICAL \. ' 1\. J /, ~ I STIFF, "20 TAPER 7 \ I I I~ ~-- ( // ----'1/ r-- son. CYLINDRICAL if' I I r.---- SOFT, "20 TAPCR _,,,,,.... .{v ._. __ ... ir---~ r-' "-....., p--- 2500 115() 1100 1000 800 m !CURVE NO.I 11571 1.tti 01 Oii 1 1~;1 iili CURVE RADIUS In! FIGURE 12 Results from WMATA truck tests (for balanced speed conditions). real-world nonlinear characteristics such as springs, sliders, wheel contours, and creep rates. It calculates forces and motions of all the compo nents. The program was used to predict pertormance of the steerable truck, and, in subsequent testing, the predictions were confirmed (Figure 19). SIMPLIFIED SECONDARY TRUCK 40 50 In high-speed applications of the P-III truck, a FIGURE 13 WMATA hushing coil spring has been used in series with the air settlement. spring so that a safe and relatively comfortable passenger ride would be maintained in the event of unlikely failure of the air spring. Another modifi cation developed in a joint prQ (Figure 16). The movement of the arms is controlled by the swivel of the bolster. The steerable trucks TILT TRUCK were tested extensively on the PATCO system and then placed in revenue service. A worn wheel contour is Another option for the P-III truck, which does not used with those tracks. There was essentially no have transit or commuter car application, is the flange wear in 50,000 miles (Figure 17). tilt truck. This option allows higher speeds around The development of the steerable truck was based curves by tilting the car body. It is intended for on nonlinear computer modeling (Figure 18) • The high-speed corridor operation. The tilt truck uses unique dynamic simulation program allows the use of a programmable roll bar to position the car body 71 SHEAR PAO ASS1Y TRACK FIGURE 15 Steering arms (truck on radius track). SIDE BEARER " ~r==__ _ -=----:;;:-~~-==--1;:n SHEAR PAD INTERFACE BOLSTER CE NI ER PIVOT AXLE FIGURE 16 Steerable truck frame. 0 MILES 10-28-6 I 41;686 MILES 12-16-82 CN-A PROFILE STEERING TRUCK CAR N0.114 WHEEL L4 114 SCALE 2X FIG URE 17 Wheel profile wear-steering truck. 72 Transportation Research Record 953 FIGURE 18 Steerable truck model. ,. . t·· 4 TEST· DATA STEERING o• 15° 30° CURVATURE FIGURE 19 Calculated angle of attack. (Figures 22-24). A pneumatic cylinder indexes the The tilt body system was developed by the Budd roll bar. The system has a simple on/off control Company and demonstrated under a contract with the actuated by lateral accelerometers. As the car en U.S. Department of Transportation with the coopera ters a curve and the acceleration exceeds a prede tion of Amtrak. Two series of tests were conducted, termined limit, the tilt system is actuated. As the and the system has been evaluated at both design and nvPr-"P""d conditions. Fiqure 25 shows the typical as the acceleration drops below another preset reduction in car body lateral acceleration from 0 .1 level. The time required to ti1t the car to the f ull .9. in the control car to O. 04 .9. in ·the tilt body car position is determined by constricting the flow of during a 2- and 1. 5-degree curve negotiation. The air to the control cylinder. The actuation time is tilt system allows a 20 to 35 percent increase in optimized for comfort for the typical spiral. speed around curves. 73 O.lGI 30 mph ~l Second_~ Standard Car Lateral Iv~ .A'~ · ~,~J\- f'/t1" \If'\_ '.! t1u ,1 J'Jif ~ii 1fi'\u1 I 1!\, .:'i·1;f'.fi' ,i,V1v1f'~ ~~~' l~I\. • ·~v.i~r ' '''"'"' u,·Vr I ., v1 ;~t '11.~ ~~~ l ~~ • - ~--- - · - • Test Car Lateral \.'.f ~."~\-."\,~:~\ -1.11\ .JwJ/'vl'IJ, ~l'v\ 1Jt'1 ~~A 1 11A ·-M; .. · ···- =-----·~ ~::· WN1_' _ -- -~\Jl'.t - _---~- ____ !I ,\\~-~~ ·· ·- FIGURE 20 LIRR simplified secondary test. ~ 1 Sec.- . . >I FIGURE 21 LIRR simplified secondary test (no shocks). 74 AIR SPRING TILT AR~\ TILT ARM CYLINDER FIGURE 22 Tilt arm· ~ an d tors10 . n bar arrangP.mP.nt. TORSION .• BAR PLAN - TORSION BAR ARM TILT ARM FLOOR STRUCTURE OF fl . fl FIGURE 2:l Tilt truck me chanism. 75 SPRING PLANK FIGURE 25 Amtrak-FRA tilt test. 76 REFEN:.~CES MA-06-0025-83-1. UMTA, u.s. Department of l. D. Griffin. Urban Rapid Rail Vehicle and Sys Transportation, 1983. tems Program: Advanced Subsystem Development Program, Final Project Report. Report UMTA-IT- 06-0026-79-5. UMTA, u.s. Department of Transportation, 1979. Publication of this paper sponsored by Railway 2. P. Boyd. Wheel/Rail Force Measurement at WMATA, Systems Section. Computer-Assisted Technical Training for Railcar Maintenance Supervision G.E. SANSONE, M. TAYLOR, and M.L. WELCH ABSTRACT within available resources. In real terms the CMD is charged with the main tenance of 6,147 revenue cars, of which it must pro In order to upgrade its training program vide an average of 4, 937 each day to make up the for line supervisors (foremen), the Car trains that serve the riding public. The allocation Maintenance Department of the New York City of resources and all CMD activities are conditioned Transit Authority hired a consultant in by the requirement to meet daily service. When re 1981 to (a) conduct a comprehensive needs sources are limited, as they currently are, such analysis, (b) develop training materials resources are, and of necessity must be, allocated for those areas identified by the analysis, primarily to day-to-day activities that contribute and (c) develop an implementation plan. The directly to meeting daily service. This defines the project designed, developed, and imple basic, overriding constraint on all CMD operations mented a comprehensive curriculum of 15 (training included). technical background courses for line su Although the pressure of daily service is real pervisors. All courses are t:onducted by iJs and the shortage of financial and other resources ing an individualized, self-paced, mastery within the CMD during the past several years has based training methodology. Tn ;iililitinn t.o been """t", thP Department has nevertheless striven the courses, a complete training management to implement such long-range programs as it could to system has been designed and implemented. provide the operational support to day-to-day main This system permits the management of the tenance activities. Chief among these are the car individualized instruction program, with overhaul programs, which entail scheduled car over complete tracking and testing of each haul and special retrofit projects to increase the trainee, together with appropriate perma reliability and enhancement of the fleet. Scheduled nent record keeping. Reception has been ex mainten