Challenge H: For an even safer and more secure railway

General Track Inspection by Commercial Railway Vehicles of Kyushu Shinkansen

Mamoru Tsutaka, Kyushu Railway Company, JPN Hirokatsu Moritaka, Kyushu Railway Company, JPN Masafumi Yoshida, Kyushu Railway Company, JPN Takashi Matsumoto, Kyushu Railway Company, JPN Eiji Yazawa, Railway Technical Research Institute, JPN

1. Introduction JR Kyushu has succeeded in technical development to add inspection devices to Shinkansen commercial railway vehicles that were introduced in August 2009. These devices measure track irregularity, body vibration acceleration, and axle box vibration acceleration. General track inspection is now being conducted by remote control from PCs at the wayside1). In the period of about one year until July 2010 these Kyushu Shinkansen commercial railway vehicles had traveled around 500,000 km in operation, and inspections were made concurrently for around 25,000 km of that distance. Since general track inspection was carried out with no major breakdowns occurring during this period and it was demonstrated that there were no problems with regard to functionality and durability, this system was put into official operation from December 1, 2010. This paper provides an overall report on the general track inspection system using commercial railway vehicles of Kyushu Shinkansen.

2. Overview of the Kyushu Shinkansen 2.1 The Kyushu Shinkansen Network The Kyushu Shinkansen Kagoshima route links Hakata and Kagoshima-Chuo and is a line conforming to Shinkansen standards (maximum speed 260 km/h, track length 256.8 km, gauge 1,435 mm, voltage 25,000V-60Hz, maximum gradient 35‰, minimum curve radius 400m). The section between Shin-Yatsushiro and Kagoshima-Chuo came into operation on March 13, 2004 with the entire route coming into operation on March 12, 2011 when through-service operations with the Sanyo Shinkansen were launched (Fig. 1). With fastest traveling times of 3 hours 45 minutes between Shin-Osaka and Kagoshima-Chuo, 2 hours 59 minutes between Shin-Osaka and Kumamoto, and 1 hour 19 minutes between Hakata and Kagoshima-Chuo, the new Shinkansen network has the potential to increase the number of visitors from Honshu (the main island of Japan) and Asia and to become a starting point for regional vitalization. Major economic benefits are expected from it, in combination with the opening of JR Hakata City (Hakata Station Building). JR Kyushu has ten sets of N700 series R trains, mainly for Sanyo Shinkansen and Kyushu Shinkansen through-service operations, and nine sets of 800 series U trains, which mainly run on the island of Kyushu. This Shinkansen rolling stock is operated under the names of “Mizuho”, “Sakura” and “Tsubame” and forms a new network that is organically linked with the Sanyo Shinkansen and conventional lines. Challenge H: For an even safer and more secure railway

（800 series U set） Sanyo Shinkansen ・6-car train set Opened 03.12.2011 ・Passenger capacity: 392 Hakata to ・MT ratio: 6M Shin-Yatsushiro

Opened 03.13.2004

Shin-Yatsushiro to （N700 series R set） Kagoshima-Chuo ・8-car train set ・Passenger capacity: 546 ・MT ratio: 8M

Fig.1 The Kyushu Shinkansen Network

2.2 The 800 series U sets The first track inspection system that has been developed this time is always mounted on the 800 series U7 set, whose interior and exterior were redesigned in 2009. The distinctive features of the 800 series are its long streamlined nose, energetic pure-white body, red and gold stripes replete with Kyushu passion and pride, and black and vermilion “swallow roof” (Fig. 2). The brightly individual appearance and smart design of these trains, which run through a landscape that is bright green even in winter, are emblematic of Kyushu. The new rolling stock with inspection devices actively continues to watch tracks as the 800-1000 series. A second track inspection system was later fitted to the U9 set introduced in 2010, and the current set-up is of these two train sets to monitor the condition of the tracks on a daily basis.

Fig.2 The 800 series U set (http://www.jrkyushu.co.jp/shinkansen/syaryo_info/index.jsp) Challenge H: For an even safer and more secure railway

3. The Structure of the Kyushu Shinkansen Track Inspection System The image of the track inspection system mounted onto Kyushu Shinkansen commercial railway vehicles is as shown in Fig. 3. This track inspection system can be generally classified as a composition of five pieces of equipment: a track inspection device, a body vibration accelerometer, an axle box vibration accelerometer, a location identifier and a control PC. The track inspection system is mounted on the lead cars at both ends (Car No. 1 and Car No. 6). Technical development of each piece of equipment was launched in 2005 while gaining the consensus of the rolling sock related departments on the following points: that the equipment should take high-precision measurements, not impair the running performance and safety of the truck and not reduce cabin space2) 3) 4) 5).

Control PC

Rail Rail Body vibration accelerometer Location identifier

Axle box vibration accelerometer Track inspection device

Fig.3 Image of the System Mounted on Shinkansen Rolling Stock

3.1 Technical Development of the Track Inspection Device Kyushu Shinkansen rolling stock is all motor cars, and taking into account its contribution to our operations, large-scale remodelling of the vehicle bodies themselves is not possible. It was therefore decided to base the new track inspection system around the inertial mid-chord offset method, which can take the necessary track measurements (longitudinal level, alignment, cross level and gauge) in a cross-section, rather than around track inspection equipment that measures multiple points on the rails as in existing inspection methods (the versine method and the eccentric chord offset method). Furthermore, it was decided to construct a new track inspection system that would simultaneously record body vibration acceleration and axle box vibration acceleration, and thus not impair the basic functions of the operational rolling stock or reduce cabin space. A truck-mounted style was used for the track inspection device so that high precision inspection waveforms could be measured. The inertial method is not good at dealing with the low speed range so it was decided to install the two inspection trucks separated by more than a specified distance and have them take simultaneous recordings that would supplement one another. It was decided to constantly install these inspection Challenge H: For an even safer and more secure railway systems in commercial vehicles of Kyushu Shinkansen and record data by remote control, thereby making it unnecessary to operate rolling stock solely for inspection purposes. Technical development based around these concepts was launched in 2005. In the first two years we built an inertial mid-chord offset prototype track inspection system that was mounted on the confirming car and resolved the problem points that had been clarified by previous research and development, and we tested its accuracy and durability. In the three years from 2007, with track inspection by commercial Kyushu Shinkansen railway vehicles as our basic premise, we investigated the best method of mounting the equipment on the trucks and the specific placement in which the equipment would be deployed on the cars.

3.1.1 Design of the Kyushu Shinkansen Track Inspection Device The track inspection device is of a multi-layer construction consisting of a steel outer box and two types of sensors (two-axis rail displacement sensor, optical fiber gyroscope and servo accelerometer) on a base protected from vibration by a liquid-ring mount. The outer box has the strength required of a truck component, and sensors are arranged inside the box on a precisely composed aluminum base to form a track inspection device with high performance in terms of weight, strength, and accuracy.

Track inspection device Track inspection device

Laser beam spots

Fig.4 Track Inspection Device Challenge H: For an even safer and more secure railway

It weighs about 270 kg and its dimensions are W 2000mm / H 225mm/ D 490mm. It is possible to measure waveforms of longitudinal level, alignment, gauge and cross level with this track inspection device. As shown in Fig. 4, stable running performance is ensured by slide-mounting the track inspection device sideways into an attachment base at the center of the truck frame. Track inspection devices are mounted to the rear trucks of the lead cars at both ends (cars No. 1 and 6) to compensate for sections that cannot be measured at low speed; this also takes into consideration axle load balance and workability in the pit line at the depot.

3.1.2 The Mounting of the Track Inspection Device and the Various Tests Performed The track inspection device was built in 2009 and the tests listed below were performed before it was put into operation. The static load test and rotation test were performed in the laboratory, and dynamic strain and truck vibration acceleration were measured in tests on actual vehicles using the Kyushu Shinkansen U7 set. ・ Static load test (to check the strength of the inspection truck equipment mounting) ・ Rotation test (to check the critical velocity of the inspection truck’s hunting as well as its running stability) ・ Dynamic strain measurement (to check the circumstances in which stress occurs to the actual inspection truck) ・ Truck vibration acceleration measurement (to check the vibration characteristics of each part of a standard truck and an inspection truck) Based on the results of FEM analysis, the static load test confirmed that, under each kind of static load conditions, the circumstances in which stress occurs to the inspection system mounting fall within the design conditions. The rotation test confirmed that the inspection truck maintains sufficient running stability at speeds of more than 350 km/h under normal conditions and up to a speed of 265 km/h even when two of the yaw dampers on the rotation test stand were in failure status. After confirming basic performance in these laboratory tests, dynamic strain and truck vibration acceleration were measured in tests on actual vehicles using the Kyushu Shinkansen U7 set. It was confirmed that even at a maximum speed of 260 km/h the inspection unit mounting had a sufficient margin for allowable stress of truck frame, and also that the inspection truck and standard truck had the same running stability. In addition, stable operation was also confirmed in verification test runs held over a period of one month after the tests on actual vehicles.

3.2 The Body Vibration Accelerometer The body vibration accelerometer is mounted under the body floor near the centre of the front truck and detects acceleration in vertical and lateral vibrations.

3.3 The Axle Box Vibration Accelerometer The axle box vibration accelerometer is mounted on the underside of the axle box of both wheels of the front axle of the front truck (Fig. 5) and detects acceleration in vertical and lateral vibrations. Challenge H: For an even safer and more secure railway

3.4 The Location Identifier The location identifier is mounted on the underside of the front truck rear axle (Fig. 6). This device senses beacons that have been set every 500 m and detects positional data. This data is compared with 0.25m sampling pulses to appropriately adjust the location data included in the inspection data.

Axle Box Vibration Accelerometer Location identifier

Fig.5 Axle Box Vibration Fig.6 Location Identifier Accelerometer

3.5 Remote-controlled Inspection The control PC is mounted in the equipment room between the driver’s cab and the cabin. The components of this unit include an inspection controller, an acceleration controller, a power-supply controller and a data recorder. Miniaturization was imperative in order that the unit could fit in with other vehicle control equipment and, by making effective use of the available space, it was possible to install it in the existing equipment room without reducing the space of the cabin. Wayside notebook PCs and the onboard control PC are linked in a network to produce a system where remote control is possible of the switching on and off of the power source, the setting of initial conditions and the start and termination of inspections, the control of sensors, the setting of track irregularity threshold values, and the transmission of exceptionally large values. Its functions make it unnecessary to staff the train with an inspector or to operate rolling stock solely for inspection purposes. The system can also compensate for the inertial method’s weakness when it comes to low speeds by synchronizing inspections between cars No. 1 and 6.

＜Waysaide PC＞ ＜ ＞ Automatic Control U set

Transmission of exceptionally large values

Fig.7 Image of Inspection under Remote Control by Waysaide PC Challenge H: For an even safer and more secure railway

4. Comparison of Track Measurement Waveforms The greatest benefit of track inspection using trains in operation is the ability to take track measurements with a high degree of freedom, unhindered by constraints of time and organization. Two test train numbers were chosen at random in operation of U7 train sets making eight or nine round trips a day between Shin-Yatsushiro and Kagoshima-Chuo on the Kyushu Shinkansen, and Fig. 8 shows the measurement result gathered automatically by PCs at the wayside remotely controlling the track inspection devices. The section measured is a flame-shaped slab section within an R 4,000 and C 200 right circular curve including 15‰ downhill gradient and level section gradient change points. From the four measurement wave forms lined up in the legend, wave forms were found to match with a high degree of accuracy for both 10 m chord longitudinal level irregularity and 10 m chord alignment even at the maximum speed of Kyushu Shinkansen rolling stock of 260 km/h. Repeatability error with the track inspection device on the No. 1 car of test sample train 1 as the benchmark was σ= 0.09 to 0.14 mm (max difference 0.23 to 0.35 mm) for longitudinal level irregularity andσ= 0.10 to 0.14 mm (max difference 0.33 to 0.42mm) for alignment. As measured track measurement waveform has high repeatability, the mounting method was proved to be adequate.

Car NO.1 (Test sample train 1) Vavg=257km/h Car No.1 (Test sample train 2) Vavg=260km/h Car No.6 (Test sample train 1) Vavg=257km/h Car No.6 (Test sample train 2) Vavg=260km/h

σ =0.09

σ =0.08

σ =0.14

10mchord longitudinal level

t

σ =0.10

ａｌｉｇｎｍｅｎ σ =0.12

σ =0.14

10mchord 2mm 20m

Fig.8 Repeatability of Track Inspecion Waveforms Measured by Shinkanse Rollingu Stock in Operation Challenge H: For an even safer and more secure railway

5. The Maintenance System In order to carry out constant and steady track measurement using commercial railway vehicles, it is essential that the track inspection system can be stably and swiftly mounted and dismounted during truck inspections, general inspections of the car and in emergencies. A jig (Fig. 9) was therefore built for the mounting/dismounting of the track inspection device on the pit line at the depot. This equipment consists of two jigs: one that fits within the gauge and one for use outside of the gauge. When the inspection unit is removed from the inspection truck it is supported on the inner jig and fed sideways in the direction of the sleeper and onto the outer jig. This process is reversed when the inspection unit is mounted. The outer jig is not only used when mounting or dismounting the track inspection system. It has a cover which makes it into a case that can be used to transport the inspection system unit. It is thus possible to take the unit on the jig to the depot for a prompt inspection.

Track inspection device

Mounting/Dismounting Equipment

Fig.9 Mounting/Dismounting Equipment

6. Conclusion Adding comprehensive track inspection devices to commercial railway vehicles of Kyushu Shinkansen has made high frequency monitoring possible and has led to improved safety. The introduction of this system not only rendered the track inspections that had been carried out at night by inspectors in maintenance vehicles unnecessary but also did away with the need for specialized inspection vehicles, thereby contributing greatly to a reduction in initial costs and running costs. In conjunction with the opening of the entire Kyushu Shinkansen Kagoshima route, JR Kyushu is combining the launch of new sightseeing limited expresses and the opening of new highway bus routes to build a new transport system centred on the Shinkansen. We will continue working to bring forth innovations that will further boost the safety and comfort of the Shinkansen, the core component of this network. Challenge H: For an even safer and more secure railway

Bibliography 1) Moritaka, Matsumoto, Yazawa: “Inspection Performance Evaluation of the Inertial Mid-Chord Offset Track Inspection System Installed in Commercial Railway Vehicles of Kyushu Shinkansen”, Japan Society of Civil Engineers 65th Annual Conference, 4-208, September 2010 2) Tsubokawa, Yazawa, Moritaka, Matsumoto: “Building an Inertial Mid-Chord Offset Track Inspection System for Long-Term Durability Tests for the Kyushu Shinkansen”, Japan Society of Civil Engineers 62nd Annual Conference, 4-285, September 2007 3) Moritaka, Matsumoto, Yazawa, Tsubokawa: “The Results of Durability Tests on the Inertial Mid-Chord Offset Track Inspection System for Installation in the Confirming Car”, Japan Society of Civil Engineers 62nd Annual Conference, 4-288, September 2007 4) Moritaka, Matsumoto, Yazawa, Tsubokawa: “A Performance Evaluation of the Inertial Mid-Chord Offset Track Inspection System and a Consideration of Measuring Methods at Low Speeds”, Japan Society of Civil Engineers 63rd Annual Conference, 4-37, September 2008 5) Tsubokawa, Yazawa, Moritaka: “Development of a High-Precision Reflector for a 2 Axle Rail Irregularity Detection System”, Japan Society of Civil Engineers 63rd Annual Conference, 4-38, September 2008 6) Yazawa, Okai: “Performance Upgrades Aimed at the Practical Use of an Inertial Mid-Chord Offset Track Inspection System”, Railway Technical Research Institute Reports, Vol. 18, pp35-40, March 2004