Magnetic Levitation Train, also maglev train, a high-speed ground transportation vehicle levitated above a track called a guideway and propelled by magnetic fields (see Magnetism). Magnetic levitation train technology can be used for urban travel at relatively low speeds (less than 100 km/h, or less than 62 mph). For example, a short-distance maglev shuttle operated for 11 years from 1984 to 1995 between the Birmingham, England, airport and the city train station. However, the greatest worldwide interest is in high-speed maglev systems. Train speeds of 552 km/h (343 mph) have been demonstrated by a full-size maglev vehicle in Japan, while in Germany a maglev train has run at 450 km/h (280 mph) and in China a maglev train has reached a peak speed of 432 km/h (268 mph).
Two different approaches to magnetic levitation train systems have been developed. The first, called electromagnetic suspension (EMS), uses conventional electromagnets mounted at the ends of a pair of structures under the train. The structures wrap around and under either side of the guideway. The magnets attract up toward laminated iron rails in the guideway and lift the train. However, this system is inherently unstable; the distance between the electromagnets and the guideway, which is about 10 mm (3/8 in), must be continuously monitored and adjusted by computer to prevent the train from hitting the guideway. A track 31.5 km (19.6 mi) long in Emsland, Germany, was used extensively to test this approach. As a result of these tests, the German government granted a commercial license to Transrapid International (TRI), a company headquartered in Berlin, Germany, to develop maglev systems based on the EMS design.
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