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.