MAGLEV GUIDEWAY ON THE YAMANASHI TEST LINE

Abstract

Connecting Tokyo and Osaka in one hour requires a speed of 500 km/h. The speed of 500 km/h is difficult by conventional railway utilizing adhesion between the wheels and rails. A super-high-speed transport system with a non-adhesive drive mechanism which is independent of wheel-and-rail frictional forces has been a long-standing dream of railway engineers. The magnetically levitated transport system (Maglev), a combination of superconducting magnets and linear motor technology, realizes super-high-speed running, safety, low environmental impact, and minimum maintenance. In overcoming the limitations of the facilities at the Miyazaki Test Track, a new Maglev test line was awaited. In 1990, the Ministry of Transport (MOT) authorized the construction of the Yamanashi Maglev Test Line as a national project, and officially nominated Railway Technical Research Institute (RTRI), Central Japan Railway Company, and the Japan Railway Construction Public Corporation as the three bodies responsible for the execution of the project. The Yamanashi Maglev Test Line is located about 100 km west of Tokyo. The test line is designed with a minimum radius of curvature of 8,000 m and a maximum gradient of 4%. Two train sets will be operated on the line to test a 550km/h maximum run. A certain section of the test line will be a double track where it will be possible to study the dynamics of trains passing each other at a relative speed of 1,000 km/h. Being an experimental facility, the Yamanashi Test Line will comprise different systems laid out in parallel for comparisons of function, cost, and reliability. In this paper, the basic configuration of the guideway for the Yamanashi Test Line is discussed. There are three kinds of structures for the sidewalls on which the ground coils are fixed. They are the beam-type, the panel-type, and the direct-attachment-type sidewalls. All of the ground coils have been manufactured and are now being installed on the guideway. In the summer of 1995, a three-car train set was delivered, and in autumn the substations began to be supplied with electricity. Thus the construction entered the final stage. Running tests will commence on the Yamanashi Test Line in the spring of 1997. Based on the published test data and analyses of Maglev, international research collaboration and cooperation regarding high speed vehicle behavior is possible. After three years of testing, in the year 2000, the prospects of Maglev commercialization will be made clear.

1. INTRODUCTION

The examination of the development of a new system of super-high-speed railways was begun two years before the 1964 inauguration of the Tokaido Shinkansen. Before the completion of the connection of Tokyo and Osaka by three hours of travel time, the engineers and researchers of the Japanese National Railways began to set a new goal of one hour travel time between the two cities.
Connecting Tokyo and Osaka in one hour requires a speed of 500 km/h. The speed of 500 km/h is difficult by conventional railway utilizing adhesion between the wheels and rails. A super-high-speed transport system with a non-adhesive drive mechanism which is independent of wheel-and-rail frictional forces has been a long-standing dream of railway engineers. The magnetically-levitated transport system (Maglev), a combination of superconducting magnets and linear motor technology, realizes super-high-speed running, safety, low environmental impact, and minimum maintenance.
The research and development of Maglev adopting superconducting technology has been underway at the Railway Technical Research Institute (RTRI) since 1970. After fundamental laboratory tests to verify the feasibility of high-speed running, the test runs of the experimental vehicle ML100 with on-board superconductive magnets was opened to the public at the RTRI Kunitachi institute in October 1972, which was also the railway centennial in Japan. After this demonstration, the construction of a 7-km test track began in Miyazaki Prefecture in 1975. Test runs of ML-500 on the inverted-T-shaped guideway started in 1977. The unmanned ML-500 attained a speed record of 517 km/h in 1979. The guideway was then modified to the U-shaped guideway. Experiments using MLU001 was started in 1980. Government subsidies to Maglev development were introduced after these experiments. The manned two-car vehicle MLU001 registered a speed of 400.8 km/h in 1987. Following the privatization and division of the Japanese National Railways, the test vehicle MLU002N debuted in 1993. MLU002N achieved a speed record of 431 km/h on the Miyazaki Maglev Test Track in 1994, and a manned-test-run record of 411 km/h in January of 1995.

Figure1. Overview of Yamanashi Test Line

2. CONSTRUCTION OF THE YAMANASHI TEST LINE

In overcoming the limitations of the facilities at the Miyazaki Test Track, a new Maglev test line was awaited. An ad hoc committee within the Ministry of Transport (MOT) for the development of Maglev systems discussed and decided on Yamanashi Prefecture as the best candidate for the new test line. In 1990, MOT authorized the construction of a Yamanashi Maglev Test Line as a national project, and officially nominated RTRI, Central Japan Railway Company, and the Japan Railway Construction Public Corporation as the three bodies responsible for the execution of the project. This nomination established that the feasibility of Maglev operation will depend on the results of experiments on this line.
The Yamanashi Maglev Test Line is located about 100 km west of Tokyo. The test line is designed with a minimum radius of curvature of 8,000 m and a maximum gradient of 4%. Two train sets will be operated on the line to test a 550-km/h maximum run. A certain section of the test line, 12.8 km long, will be a double track where it will be possible to study the dynamics of trains passing each other at a relative speed of 1,000 km/h.
Being an experimental facility, the Yamanashi Test Line will comprise different systems laid out in parallel for comparisons of function, cost, and reliability. Equipped with computers and a high-speed fiber-optic communications network, the facilities of the test line are capable of rapidly processing tremendous volumes of data on the vehicle and wayside structures. In the original plan, the test line was designed to be 42 km long. But to gain a perspective on Maglev realization as early as possible and because of the difficulty of land purchase, an 18.4-km portion of the test line was designated as a priority section, and the work began on this section. In 1994 the tunnels were all bored, which account for 80% of the entire test line. In the summer of 1995, a three-car train set was delivered, and in autumn the substations began to be supplied with electricity. Thus the construction entered the final stage. Running tests will commence on the Yamanashi Test Line in the spring of 1997. After three years of testing, in the year 2000, the prospects of Maglev commercialization will be made clear.

Figure 2. Facilities on the Yamanashi Test Line

3. THEMES OF MAGLEV DEVELOPMENT

Maglev research at RTRI is widely diversified. Maglev represents a composition of a broad scope of available technologies. Even one bottleneck will deny its realization. The elemental technologies to be utilized on the Yamanashi Test Line have been basically established, and confirmed on the Miyazaki Test Track.
Firstly, the research focuses on the stability of the superconducting magnet at cryogenic temperatures, because all three forces of levitation, propulsion, and guidance would be lost if the magnet fails. The phenomena of the superconductive state collapsing suddenly (quenching) have been analyzed and tested from many aspects. Rigorous tests have been repeated under mechanical vibrations and electromagnetic disturbances. In consequence, the heat generation within the cryostat housing the superconducting coils has been quantified to establish countermeasures. Figure 3 shows an exterior view of the superconducting magnet installed on the test vehicle. Table 1 shows the main characteristics.

Meanwhile, the cryostat must be light and robust. At the same time the on-board refrigeration system to re-liquefy the helium gas vaporized within the cryostat must also be light and small. These objectives have been accomplished with high efficiency.

Figure 3. First train set with 3 cars

Figure 4. Superconducting magnet

4. MAGLEV GUIDEWAY

Figure 5 shows the basic configuration of the guideway for the Yamanashi Test Line. Guideway with coils correspond to the rails of conventional railways. Accuracy of the guideway setting directly affects riding confort of the vehicle. Requirement of high-precision of the guideway setting results in cost increase. However pursuing the riding comfort and cost effctiveness at the same time, cost increase is also attempted to be maintained at the same level. In an effort to reduce the cost of the guideway, three types of guideway are constructed on the Yamanashi Test Line. The first type is the beam-type. The beam type adopts a prestressed concrete (PC) box with coils. The PC box is made at an on-site factory and coils are attached to the box. The PC box beam is set onto concrete shoes on the guideway. The length of the beam is 12.6 m. Panel type consists of a concrete slab with coils. The length of the panel is also 12.6m. These panels are constructed at an on-site factory and where coils are attached to the panels. On the guideway, these panels are attached to the sidewalls. The third type of the guideway is direct-attachment type. The coils are directly attached to the sidewalls in the guideway.
During coil installation, a required accuracy of coil installation was plus minus 4mm both in the vertical and horizontal axes. The required accuracy of coil installation was applied to all types of guideway and decided from the point of riding comfort. The accuracy of coil installation was checked on the guideway in each case. Even though the method of installation was different in the three guideway types, the required accuracy was maintained sufficiently.
Two groups of power converters are installed on the Yamanashi Test Line, because two train sets will be operated concurrently according to the test plan. Each group of power converters consists of one converter and three inverters. A GTO inverter with PWM control is employed in both groups. Figure 6 shows an exterior view of the power converter station.

Figure 5. Basic configuration of the guideway

Figure 6. Power converter station

5. COLLABORATION/COOPERATION POSSIBILITIES

In an effort to comprehend the vehicle movement during high-speed running, test runs at over 500 km/h will be conducted repeatedly on the Yamanashi Test Line. Test run data will be processed and tabulated for analysis. Aerodynamic phenomena and vehicle behavior will be analyzed and simulated in various ways.
Even though the propelling and guiding systems are different, these Maglev running data are useful for design and analysis of conventional railway vehicles during high speed running. Based on published test results and analyses of Maglev, international research collaboration and cooperation regarding high speed vehicle behavior is possible. The authors are eager to discuss this issue with researchers and engineers from all over the world in the future.

Quelle: Railway Technical Research Institute
Autor: Fuminao Okumura, Hajime Takagi