Magnetic levitation technology was initially invented by a French and an American engineer who did not see practical use of the technology back in early 1900s. As leaders in the rail system, Germany and Japan saw the potential use of magnetic levitation technology and applied it to passenger rail since there is growing demand for reliable high speed mode of transportation around the world due to increasing population growth and mobility. Up until now a number of firms have been researching this technology, but the only two that are at or near commercial implementation are Transrapid International of Germany and the JR-Maglev of Japan. This case study will explore the trend in magnetic levitation technology with the focus in Asia.
Maglev Train Technology
Maglev: derives from "Magnetic levitation", is a system of transportation that suspends, guides, and propels vehicles, by using a very large number of magnets for lift and propulsion.
There are three primary functions basic to maglev technology: (1) levitation or suspension; (2) propulsion; and (3) guidance. Magnetic forces can be used to perform all three functions, although a nonmagnetic source of propulsion could be used as well. However, currently no consensus exists on an optimum design to perform each of the primary functions.
Linear motor: refers to an electric motor with stator and rotor "unrolled" use to produce a force to guide the vehicles in linear pattern. It does not require physical contact between the vehicle and guideway. It has become a common fixture on many advanced transportation systems, including Maglev.
Guideway: refers to a form of track with a specific arrangement of magnets that allowed a single linear motor to produce both lift as well as forward thrust. There are various guideway configurations, such as, T-shaped, U-shaped, Y-shaped, and box-beam, made of steel, concrete, or aluminum.
There are two main types of suspension systems of maglev train technology. One type uses electromagnets, while the other uses superconducting magnets. Germany's Transrapid bases its research and development of maglev on electromagnetic suspension (EMS) while Japan's JR-Maglev focuses on electrodynamics suspension (EDS).
Three primary functions basic to maglev technology
Suspension Systems
1. Electromagnetic Suspension (EMS): electromagnets in the train attract it to a magnetically conductive track. This is the most used system also called "attractive" because an electromagnet is "attracting" the guideway above. An example of EMS is in Germany's Transrapid Maglev.
Transrapid Maglev
The train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below. However, it cannot propel the train forward. It needs propulsion technology of linear motor mounted in the track (propulsion coils, a propeller, or jet engine).
The EMS systems rely on active electronic stabilization to measure the bearing distance and adjust the electromagnet current accordingly. It is necessary to maintain a train at a constant distance from the track, because changes in distance between the magnets and the rail produce greatly varying forces.
The major advantage to suspended maglev systems is that they work at all speeds. This eliminates the use of wheels or secondary propulsion system and there is no need for a separate low-speed suspension system. It leads to simplification of the track layout.
On the downside, the system is instable. The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction.
2. Electrodynamic Suspension (EDS): electromagnets on track and train to push the train away from the rail, creating a repelling force of magnets. An example is the Japanese JR-Maglev. It uses superconducting electromagnets, cooled to a very low temperature by liquid nitrogen. This electromagnet can conduct electricity in case the power supply is out. The guideway is "U" shaped and has an "active" systems required to make the train run.
JR-Maglev
The advantage of the repulsive maglev systems is a large margin between rail and train allow higher speed ability and heavier load capacity. Stability, where only a minor difference in distance creates or reduces forces that return the magnets back to their original position.
A downside is that EDS are moving system; it cannot levitate the train unless it is in motion. When the train is at slow speeds, the current induced and magnetic flux is not enough to support the weight of the train. Wheels are required to support the train until it reaches a speed that can sustain levitation. The entire track must be able to support both low-speed and high-speed operation.
Difficulties that prevent EDS system for commercial train is its strong magnetic fields onboard the train would make the train inaccessible to passengers with pacemakers or magnetic data storage media such as hard drives and credit cards.
Propulsion Systems
1. "Long-stator" propulsion: uses an electrically powered linear motor winding in the guideway enables high-speed maglev systems. It is also the most expensive because of higher guideway construction costs.
2. "Short-stator" propulsion: uses a linear induction motor (LIM) winding onboard and a passive guideway. It reduces guideway costs, but the LIM is heavy and reduces vehicle payload capacity, resulting in higher operating costs and lower revenue potential compared to the long-stator propulsion.
3. A nonmagnetic energy source: gas turbine or turboprop, but it also results in a heavy vehicle and reduced operating efficiency.
Guidance Systems
Guidance or steering: the sideward forces with either attract or repulse, make the vehicle follow the guideway. The same magnets on board the vehicle, which supply lift, can be used concurrently for guidance or separate guidance magnets can be used.
Advantages of Maglev Train compare to conventional train
Maintenance Requirements: with Maglev, there is minimal need for guideway maintenance. The maintenance schedules based on hours of operation, not on speed or distance traveled. Conversely, traditional rail is subject to wear and tear from numerous usage and the rate increases as speed increases. Maglev offers reliability, availability and sustainability that traditional train cannot provide.
All-Weather Operations: Maglev trains operations are not affected by snow, ice, severe cold, rains or high winds because they are non-contact systems. While bad weather conditions prevent traditional friction-based rail systems from operating.
Efficiency: lack of physical contact between track and vehicle, maglev trains experience no rolling resistance. Most of the energy is used for propulsion and overcoming the air friction resistance, which consume less energy than traditional trains and improves power efficiency. It could be an alternative transportation more through reducing air and highway congestion, air pollution, energy use, and releasing slots for more efficient long-haul service at crowded airports.
Noise: the major source of noise comes from displaced air, therefore, it produces less noise than a conventional train at equivalent speeds.
High reliability: high peak speed and high acceleration and braking enable to lower trip time than high-speed rail or air. An intra and intermodal connecting times can be reduced to a few minutes rather than the half-hour or more with airlines.
Petroleum independence: Maglev is electrically powered. Therefore, eliminate the problem of oil availability crisis. Therefore, the system is environmentally friendly because it causes less pollution with respect to air and auto transportation. Emissions can be controlled more effectively at the source of electric power generation.
Disadvantages of Maglev Train
Backwards Compatibility: Maglev trains currently in operation are not compatible with conventional track, and therefore require all new infrastructures for their entire route.
Specific case of Shanghai Maglev
Germany's Transrapid International is a joint firm of Siemens and Thyssen Krupp which use EMS technology. In 2001, the construction of Shanghai Maglev or Shanghai Transrapid connecting Shanghai Pudong International Airport to the outskirts of central Shanghai commenced. The maglev trains in this project were manufactured in Germany by Transrapid International while the guideway was fabricated in Shanghai based on German-Chinese Technology. Most of the engineering work for the guideway construction was supplied by ThyssenKrupp Company. The Shanghai Maglev is operated by Shanghai Maglev Transportation Development Company (SMTDC). As of 2008, Shanghai Maglev is the only commercial high-speed maglev train in operation.
Following the construction of Shanghai Maglev as well as Maglev research and development by SMTDC, China unveiled its first Chinese Maglev passenger cabin design based on German licenses; indicating some levitation, guidance, and propulsion components were based on German technology.
Specific case of JR-Maglev
Since 1964, the main traffic mode of transportation for the Tokyo-Osaka corridor (500 kilometers), the Japan's busiest transportation corridor, is the Tokaido Shinkansen (high speed bullet train) which travels at a maximum speed of 270 kilometers per hour (km/hr), taking travel time per trip of 150 minutes. Considering the number of trips this service offers per day translates to transporting 140 million passengers per year, or more than 40 billion passenger-kilometers per year. Therefore, this service is superior to traveling on the road or by air. However, there still remains a large volume of demand that exceeds the capacity of the Tokaido Shinkansen, leading to the need for an additional high speed train line between Tokyo and Osaka.
After considering viewpoints (factors) of speed, safety, maintenance, pollution, and future prospects, JR or Japan Railways Group's choice of high speed train systems for Tokyo-Osaka corridor is maglev train with superconducting magnets (EDS) and is driven by a Linear Synchronous Motor (LSM) System which is needed to supply power to the coils at the guideway. While Germany focuses its maglev technology on electromagnetic system, Japan instead chooses to focus on electrodynamics system mainly because of higher speed potential and is more suitable for the nation's mountainous terrain and frequent earthquakes. The larger air gap provided in EDS accommodates the ground motion experienced in Japan's earthquake-prone territory.
Maglev project in Japan is lead by the Central Japan Railway Company (JR Tokai) which believes that conventional railroad technology is approaching its peak performance (limit). JR-Maglev is aimed to be the successor of Shinkansen bullet train. The Japanese government granted a budget for superconductivity research of 20 trillion yen or approximately 180 billion US dollars in 1996.
History of JR-Maglev
An EMS maglev has been under development in Germany since the late 1960s, and an EDS program was initiated in Japan and has been under development for about the same period. The development of JR-Maglev began 1962 by the Central Japan Railway Company and Railway Technical Research Institute (association of Japan Railways Group); it was nationally funded. In 1977, test run of ML-500 vehicle on inverted-T guideway was started at Miyazaki track and reached 517 kilometers per hour by 1979. However, an accident occurred in 1991 that destroyed the train resulting in a new design. The Miyazaki track ceases operation in 1995 and a new test operation on maglev train model MLX01 began in the 42.8 kilometers Yamanashi Test Line in 1996. JR-Maglev MLX01 is one of the latest designs of a series of maglev trains in development in Japan since the 1970s. The fastest speed of the maglev train reached 581 kilometers per hour in December 2003, setting the world speed record in a manned vehicle run.
After 40 years of maglev R&D, in 2000, the Maglev Practical Technology Evaluation Committee of the Ministry of Transport of Japan concluded that the JR-maglev has the practicability of high speed transportation system, but addressed concerns regarding long-term durability and reliability, cost reduction and improved aerodynamics. Therefore, the second technical phase has been under operation since 2000. The Tokyo-Osaka JR-Maglev is expected to begin commercial operations in 2025 and is intended to replace the bullet train. JR-Maglev will be owned by the Central Japan Railway (current owner of Shinkansen bullet train).
Case Questions
Can Maglev train technology shift the s-curve of conventional train?
Between two leading Train system countries, will there be a de facto standard?
Will other countries adopt the technology? Will the company be able to cross the chasm?
Appendix
Patents History
High speed transportation patents were granted in the United States for a linear motor propelled train to the inventor, Alfred Zedekiah (German) in June, 1907.
In 1907, another early electromagnetic transportation system was developed by F. S. Smith. A series of German patents for magnetic levitation trains propelled by linear motors were awarded to Hermann Kemper between 1937 and 1941.
An early modern type of maglev train was described in U.S. Patent 3,158,765, Magnetic system of transportation, by G. R. Greenfly (August 25, 1959).
Timeline: History of Maglev research in Germany and Japan
Germany
Transrapid 01 1969- Built by Krauss-Maffei, first practical EMS levitation vehicle
Transrapid 02 1971- Operated by K-M on a .93km track with EMS, max speed 164km/h
Transrapid 03 1972- Operated by K-M on .93km track, max speed 140km/h
Transrapid 04 1973- Operated by K-M on a 2.4km track, EMS support
HMB1 1975- First vehicle with long armature LSM and EMS by T-H
HMB2 1976- First passenger-carrying vehicle by Thyssen-Henshel
Transrapid 05 1979- Emsland Test Facility started; Carried passengers up to 75km/h
Transrapid 06 1983/4- First 21.5 km of Emsland opened; 302km/h achieved
Transrapid 07 1993- Achieves speed of 450 km/h
Transrapid 08 1999- Current system; Is the only COTS system available today.
Japan
1972- Experimental superconducting maglev test vehicle ML-100 succeeded in 10 cm levitation.
1977- Test run of ML-500 vehicle on inverted-T guideway
1979- Unmanned ML-500 test vehicle achieved speed record of 517 km/h (321 mph)
1980- Test run of MLU001 vehicle of U-shaped guideway
1987- Speed of 400.8 km/h (249 mph) ahieved by 2-car manned vehicle
1990- Yamanashi Maglev Test Line construction plan approved
1996- 18.4km section of YMTL completed; MLX01 (3 cars) delivered
1997- Tests of MLX01 started. Speed record of 550 km/h (342 mph) on 12/24/97
1999- New speed record of 552 km/h (343 mph) in TMTL
