Maglev Guideway Construction (yamanashi Maglev Test Line)

Guideway of the Yamanashi Maglev Test Line

Guideway of the Yamanashi Maglev Test Line

The guideway consists of a structure corresponding to the conventional track and ground coils corresponding to the conventional motor. It is a vital element of Maglev. For the Yamanashi Maglev Test Line, the following methods of installing the ground coils for propulsion, levitation, and guiding to the guideway are adopted, out of which the best one for commercial operation will be selected.

Beam Method

In the beam method, the sidewall portion will be constituted solely of concrete beams. The entire process from beam manufacturing to installation of the ground coils take place at the on-site factory (provisional yard). A finished beam is transported to the work site within the guideway, to be placed on two concrete beds set up in advance there.

Panel Method

In a factory set up on-site (provisional yard) the concrete panel is produced and attached with ground coils. The finished assembly is carried to the work site, where it is fixed, with 10 bolts, to the concrete sidewall erected in advance there.

Direct-Attachment Method

At the work site in the tunnels or on the bridges a concrete sidewall portion is produced. At the same site the finished sidewall is directly fitted with the ground coils. With no need for the factory or transport vehicle, this method is economically superior to the other two, but its drawback lies in that it allows only slight adjustments of individual ground coils to correct the irregularities.

New Method

Former three types of sidewalls were adopted as the guideway structure to evaluate their functions and clarify merits and defects. We developed the new type guideway structure taking advantage of the merits based on the evaluation results. We placed emphasis on the improvement of the efficiency of installing sidewalls to concrete roadbed, as a means to reduce costs for the construction or maintenance. We discussed a shape of the sidewall in all aspects of the efficient installation, and eventually adopted an invert-T-shaped sidewall.

Turnout Facilities of the Yamanashi Maglev Test Line

Turnout Facilities of the Yamanashi Maglev Test Line

The turnout facilities (switches) are an indispensable element for

distributing the train routes. Depending on the train speed dictated by the purpose, there are three types, for high speed, for low speed, and for the train depot. On the Yamanashi Maglev Test Line, they are selectively employed for testing purposes.

High-speed (traverser) type

A traverser is installed to switch routes between the straight main line where the vehicle runs levitated at high speed and the curved branch line where the vehicle runs on wheels at low speed. In the high-speed (traverser) type, the guideway is divided into several laterally movable beams, which shift to switch routes. On the Yamanashi Maglev Test Line, two shift-drive systems, electrical and hydraulic, are tested.

Low-speed (sidewall-shifting) type

The sidewall-shifting type is employed at terminals where the line starts and ends; and where low-speed wheel runs takes place on the straight main line and curved branch line. In this type the route is formed by merely shifting the sidewalls, instead of the girder, vertically or laterally. The front and rear ends permit the sidewalls to be moved laterally, while the midpart permits the sidewalls to be moved vertically.

Train-depot type For the Yamanashi Maglev Test Line, the train-depot type is adopted on the section where the vehicle is place on a tractor-pulled run. In this type, the vehicle is guided along the guide rail on the ground.

Boarding Facilities of the Yamanashi Maglev Test Line In the Maglev operation, for the purpose of shielding the passengers from

the magnetic fields of the SCMs, boarding facilities resembling boarding bridges at airports are installed on the platform so that the passengers can safely get on or off the train.

Test platform (extending type)

This is a four-layered box-like structure making a passage that extends and contracts like bellows.

Test platform (rotating type)

This is a three-sided structure consisting of a floor and two sidewalls. For boarding, a pair of doors on the platform side rotate 90 degrees and sliding boards emerge, making a passage.

Ground Coils of the Yamanashi Maglev Test Line

Propulsion Coil

Levitation Coil

For the superconducting LSM (LSM; Linear Synchronous Motor), the

ground coil is an essential element corresponding to the armature in the conventional motor and to the conventional rails. The ground coils come in two types: propulsion coils to propel the vehicle and levitation coils serving both to levitate the vehicle and to guide it laterally. When electric current flows in these coils fitted to the guideway, the Maglev vehicle can run. On the Yamanashi Maglev Test Line, the propulsion coils are arranged in two overlapping layers to reduce the external electromagnetic disturbances influencing the Superconducting Magnet; and the levitation coils are placed on these propulsion coils. Both the propulsion coils and the levitation coils are wound aluminum conductors and molded with resin. The propulsion coils are required to be electrically insulated and mechanically strong, while the levitation coils are required mainly to be mechanically strong. Therefore the propulsion coils are moldings of epoxy resin, while the levitation coils are moldings of unsaturated polyester resin respectively reinforced with glass fiber.

Electrical Facilities of the Yamanashi Maglev Test Line

External view of the inverter unit

The inverter installed at the substation for power conversion is a facility to transform the power supplied from the utility company at commercial frequency into one of a frequency required for train operation.

For the Yamanashi Maglev Test Line there are inverters provided in three sets respectively for three phases, of 38 MVA for the north line and 20 MVA for the south line. Depending on the train speed, the north line inverters give a frequency output of 0-56 Hz (550 km/h) and the south line inverters give a frequency output of 0-46 Hz (450 km/h). The operation control system at the test center formulates run curves, which in turn instruct the drive control system at the substation for power conversion.

SCM of the Yamanashi Maglev Test Line

SCM of the Yamanashi Maglev Test Line

The SCM (SuperConducting Magnet) is the core element of superconducting Maglev. Two SCMs are mounted on each bogie. Each SCM of the Yamanashi Maglev Test Line consists of 4 SC coils. The SCM features high reliability and high durability, embodying the achievements of the Miyazaki Maglev Test Track and RTRI (Kunitachi, Tokyo). The cylindrical unit at the top is a tank holding liquefied helium and nitrogen. The bottom unit is an SC coil alternately generating N poles and S poles. At one end of the tank is the integrally-attached on-board refrigerator, which serves to re-liquefy the helium gas once vaporized by regular heat absorption and external disturbances during running.

SCM of the Yamanashi Maglev Test Line (cut model) Pole pitch

Layout Fitted height 4-pole, 2-row 0.57 m 1.35 m (symmetrical on both sides) (height above SC coil center in wheel run) SC coil dimensions Magnetomotive force Left-right spacing Length x width 1.07 m x 0.5 m 700 kA 2.98 m (race track) Car-mounted refrigeration system Circular re-liquefaction by direct cooling

MLX01

MLX01 leading car, aero-wedge

MLX01 leading car, double cusp

New leading car, MLX01-901

MLX01 (X means Experimental) is the train set (composed of maximum 5 cars) to run on the Yamanashi Maglev Test Line. The leading cars are designed in three styles: aero-wedge, double cusp, and new MLX01-901, to minimize aerodynamic resistance in high-speed run. And in anticipation of trial riding some intermediate cars are provided with seating space. MLX01 is complete with on-board backup brakes, namely aerodynamic brakes and disc brakes, well proven on MLU001 and MLU002N at the Miyazaki Malgev Test Track. Carbody dimension (m) Number built Seating capacity Length x width x height leading car: 28.0 x 2.90 x 3.32 leading car: 5 standard intermediatecar: 21.6 x standard intermediate long intermediate 2.90 x 3.32 car: 2 car: 68 long intermediate car: 24.3 x 2.90 x long intermediate car: 3.32 2 Superconducting Coil Max.speed(km/h) Completed year (SC coil)

Magnetomotive force (kA) x poles x rows 700 x 4 x 2

581(result)

Aerodynamic brakes

Bogie

1996-2002

Seating space

Door

ML100

ML100

ML100 (side view, dimension in mm)

ML100 is propelled by LIM (Linear Induction Motor). Built as a show-case experimental vehicle, it was intended for celebrating Japan's railway centennial in 1972. It runs astride the inverted-T guideway looking like a vertical wall. "ML" stands for "Magnetic Levitation" and "100" implies the 100th anniversary of Japan's railway. Carbody dimension (m) Weight Number Seating Length x width x (t) built capacity height 7.0 x 2.5 x 2.2 3.5 1 4 Superconducting Coil Max. (SC coil) Site of Year speed Magnetomotive run completed (km/h) force (kA) x poles x rows For levitation : 250 x 2 60 RTRI of JNR 1972 x2

MLU002N

MLU002N

MLU002N (side view, dimensions in mm)

With about the same carbody as MLU002, MLU002N was yet another experimental vehicle more oriented for commercial operation, equipped with disc brakes, aerodynamic brakes, and the resiliently-mouted SCM bogie. It served for mechanical brake testing, and confirmation of the propulsion/levitation/guiding function of the PLG Coil, in which a single sidewall coil was responsible for propulsion, levitation, and guiding. MLU002N in 1995 successfully registered the highest speed of 411 km/h in a manned run at the Miyazaki Test Track. Carbody dimension (m) Weight (t) Length x width x height 22.0 x 3.0 x 3.7 19.0 Superconducting Max. speed

Number built

Seating capacity

1 Site of run

12 Year

Coil (SC coil) Magnetomotive force (kA) x poles x rows 700 x 6 x 2

(km/h)

completed

unmanned: Miyazaki Maglev Test 431 Track manned: 411

Aerodynamic brakes

1993

Resiliently-mounted the SCM bogie (double-layered bogie)

MLU002

MLU002

MLU002 (side view, dimensions in mm)

MLU002 was an experimental vehicle taking the place of MLU001 and built with the prototype bogie style to serve as the design base for future commercial cars. Meant for test riding, it had seating space for 44 passengers. MLU002 performed turnout entry tests, sidewall levitating performance tests aimed at reduction of magnetic drag at low speed, and resiliently-mounted SCM bogie performance tests for improved riding comfort. Unfortunately in 1991 it was burned down in an accidental fire during test run. Carbody dimension (m) Weight Length x width x (t) height 22.0 x 3.0 x 3.7 17.0 Superconducting Max. Coil speed (SC coil) (km/h) Magnetomotive force (kA)

Number built 1 Site of run

Seating capacity 44 Year completed

x poles x rows 700 x 6 x 2

394

Miyazaki Maglev Test Track

Bogie of MLU002

MLU001

MLU001 (3-car train)

1987

MLU001 (side view)

MLU001 to serve for long-distance mass transport in the future was designed as a coach accommodating passengers. To carry passengers, the passenger room had to be located above the bogie to get clear of the inverted-T guideway, which resulted in an enlarged carbody. For this reason, instead of the inverted-T guideway a U-shaped guideway was adopted, yielding a box-like carbody. "U" in the designation MLU implies that the design was changed to a U-shape. Three cars including a middle car were built. Using MLU001, its moving characteristics have been investigated in test runs with the three cars coupled and with the guideway intentionally provided with irregularities. Carbody dimension (m) Seating Weight (t) Number built Length x width x capacity height Head cars: 10.1 x 3.0 Head cars: 8 x 3.3 Head cars: 2 10.0 Middle car: Middle car: 8.2 x 3.0 x Middle car: 1 16 3.3 Superconducting Coil (SC coil) Max. speed Year Site of run Magnetomotive (km/h) completed force (kA) x poles x rows 2-car train: 405 Miyazaki Maglev Test 700 x 4 x 2 1980-82 3-car train: Track 352

MLU001 (in aerodynamic braking tests) Even after MLU002 came into being, MLU001 remained, to be submitted to emergency landing brake tests in 1987; and after restructuring, it served again for aerodynamic braking test in 1989.

ML-500, 500R

ML-500

ML-500 (side view, dimension in mm)

ML-500 is the first-generation experimental vehicle for the Miyazaki Maglev Test Track. Initially, the Miyazaki Test Track had an inverted-T guideway, and with no space reserved to accommodate passengers, ML-500 turned out to be an unmanned vehicle. In those days, with no large SCM (Superconducting Magnet) available such as the present one, ML-500 came in two versions separately equipped with SCM for levitation and SCM for propulsion and guiding. In December 1979, ML-500 was credited with a test run at 517 km/h, the highest speed in the world then.

Incidentally, "500" in the designation ML-500 meant the target of 500 km/h. Carbody dimension (m) Weight Length x width x height (t) 13.5 x 3.7 x 2.9 10.0 12.6 x 3.7 x 3.8 12.7 Superconducting Coil (SC coil) Max. Magnetomotive force speed (kA) (km/h) x poles x rows For levitation: 250 x 2 x 2 517 For propulsion-guiding: 450 204 x4x2

Number built

Seating capacity

1

-

Site of run

Year completed

Miyazaki Maglev Test Track

1977 1979 (modified)

ML-500R ML-500R is a modified version of ML-500 mounted with a refrigerator for cooling the SCM. Using ML-500R, feasibility of manufacturing the car-mounted refrigerator has been confirmed.

FOR the past two decades, prototype magnetically levitated (maglev) trains cruising at up to 400 kilometers per hour have pointed the way to the future in rail transport. Their compelling advantages include high speeds, little friction except aerodynamic drag, low energy consumption, and negligible air and noise pollution. However, maglev trains also pose significant drawbacks in maintenance costs, mechanical and electronic complexity, and operational stability. Some maglev train cars, for example, employ superconducting coils to generate their magnetic field. These coils require expensive, cryogenic cooling systems. These maglev systems also require complicated feedback circuits to prevent disastrous instabilities in their high-speed operation. Lawrence Livermore scientists have recently developed a new approach to magnetically levitating high-speed trains that is fundamentally much simpler in design and operation (requiring no superconducting coils or stability control circuits), potentially much less expensive, and more widely adaptable than other maglev systems. The new technology, called Inductrack, employs special arrays of permanent magnets that induce strong repulsive currents in a "track" made up of coils, pushing up on the cars and levitating them. Totally Passive Technology During the past two years, a Livermore team, headed by physicist Richard Post, has successfully demonstrated the Inductrack concept in test trials. The test runs demonstrated the system's totally passive nature, meaning that achieving levitation requires no control currents to maintain stability, and no externally supplied currents flowing in the tracks. Instead, only the motion

of train cars above the track is needed to achieve stable levitation. The results have been so promising that NASA has awarded a three-year contract to the team to explore the concept as a way to more efficiently launch satellites into orbit. Inductrack involves two main components: a special array of permanent, room-temperature magnets mounted on the vehicle and a track embedded with close-packed coils of insulated copper wire. The permanent magnets are arranged in configurations called Halbach arrays, named after Klaus Halbach, retired Lawrence Berkeley National Laboratory physicist. Originally conceived for particle accelerators, Halbach arrays concentrate the magnetic field on one side, while canceling it on the opposite side. When mounted on the bottom of a rail car, the arrays generate a magnetic field that induces currents in the track coils below the moving car, lifting the car by several centimeters and stably centering it. When the train car is at rest (in a station), no levitation occurs, and the car is supported by auxiliary wheels. However, as soon as the train exceeds a transitional speed of 1 to 2 kilometers an hour (a slow walking speed), which is achieved by means of a low-energy auxiliary power source, the arrays induce sufficient currents in the track's inductive coils to levitate the train. To test the Inductrack concept, Post, project engineer J. Ray Smith, and mechanical technician Bill Kent assembled a one-twentieth-scale model of linear track 20 meters long (Figure 1). The track contained some 1,000 rectangular inductive wire coils, each about 15 centimeters wide. Each coil was shorted at its ends to form a closed circuit but not otherwise connected to any electrical source. Along the sides of the track, they attached aluminum rails on which a 22-kilogram test cart could ride until the levitation transition velocity was exceeded (Figure 2). Finally, the team secured Halbach arrays of permanent magnet bars to the test cart's underside for levitation and on the cart's sides for lateral stability. The cart was then launched mechanically at the beginning of the track at speeds exceeding 10 meters per second. High-speed still and video cameras revealed that the cart was consistently stable while levitated, flying over nearly the entire track length before settling to rest on its wheels near the end of the track. Post says the test results are consistent with a complete theoretical analysis of the Inductrack concept he performed with Livermore physicist Dmitri Ryutov. The theory predicts levitation forces of up to 50 metric tons per square meter of magnet array using modern permanent magnet materials such as neodymium-iron-

boron. The theory also shows levitation of loads approaching 50 times the weight of the magnets, important for reducing the cost relative to maglev vehicles.

External Power Needed Post notes that a power source is needed to accelerate the cart to its operating speed of 10 to 12 meters per second. The first section of the test track uses a set of electrically energized track coils--aided by a stretched bungee cord--to reach this speed. A full-scale train might use an electronic drive system, as found on experimental German trains, or even a jet turbine, as proposed by Inductrack engineer Smith. "Inductrack allows you the possibility of carrying all the power with you," emphasizes Post. Even though the electromagnetic drag associated with Inductrack becomes small at high speeds, an auxiliary power source would also be needed to maintain the train's high speed against aerodynamic drag. The amount of power needed depends on the weight of the vehicle and its maximum speed. If the external drive power ever fails, or when the train arrives at a station, the train cars would simply coast to a stop, easing down on their auxiliary wheels. In this sense, Inductrack is a true failsafe system. Livermore is one of the few institutions to explore the uses of the Halbach array. Indeed, the Inductrack

concept arose from Post's research on an electromechanical battery designed for superefficient cars and trucks (See April 1996 S&TR, "A New Look at an Old Idea."). The Livermore battery uses circular Halbach arrays both to generate power and to achieve nearly frictionless magnetic bearings that minimize the loss of stored energy. "We just unrolled the circular magnetic arrays from the electromechanical battery into a linear array on the car that seemed ideal for trains and other vehicles," he explains. The Halbach array offers other benefits besides levitation. Because its magnetic fields cancel out above the magnets, there is no worry about magnetic fields affecting passengers' heart pacemakers. In contrast, passengers must be magnetically shielded on maglev trains employing superconducting coils. The consulting company of Booz-Allen & Hamilton conducted a preliminary feasibility study of Inductrack and compared it to other maglev technologies. The study found that while an Inductrack system would cost more to build than conventional rail systems, it should be less expensive than maglev trains using superconducting coils. The study also found that Inductrack should be able to achieve speeds of 350 kilometers per hour and up and demonstrate lower energy costs, wheel and rail wear, propulsion maintenance, and noise levels.

Launching Rockets Last October, negotiations were completed on a three-

year contract with NASA to build a new Inductrack model at Lawrence Livermore to demonstrate the concept at speeds up to Mach 0.5 (170 meters per second). NASA is interested in maglev technology to help launch rockets at sharply reduced costs. As conceived, a track would use a reusable launcher to propel a rocket up a ramp to almost Mach 1 speeds before the rocket's main engines fire. According to Smith, the technology should be able to save about 30% of the weight of the launch vehicle. "Rocket engines are not fuel-efficient at low speed," he points out. The Livermore team is designing a 150-meter-long track, to be built at the Laboratory site, on which a scaled launch cradle and rocket will be accelerated. Unlike the present track, the one for NASA will interleave powered drive coils with passive levitation coils to reach the required speeds. The team is partnered with computer scientists at Pennsylvania State University, who are developing an integrated design code that includes magnetics, aerodynamics, stresses, and control stability to assess full-scale systems. Post believes Inductrack offers NASA the potential for a far less expensive technology for magnetic levitation launchers than approaches using superconducting coils. He and Smith note, however, that while the existing Inductrack model has demonstrated the principle of the concept, there are new issues to be addressed in launching rockets. Among these are high g forces, sustained speeds of Mach 0.5 or higher, the effects of fluctuating aerodynamic forces on the launching cradle and its payload, and aerodynamic and other issues associated with detachment and flight of rockets.