magnetic levitation

magnetic levitation or maglev , support and propulsion of objects or vehicles by the use of magnets. The magnets provide support without contact or friction, allowing for fast, quiet operation. In a typical system, the vehicle, which resembles a railroad car, travels above a guideway. Arrays of magnets of like polarity in both the vehicle and guideway repel each other, producing the lifting force. By continuously changing the polarity in alternate magnets, a series of magnetic attractions and repulsions is created that moves the vehicle along the track. The electrical energy required for such a system is great and the use of superconducting materials offers the only realistic potential for this means of transportation. Research into such systems has been conducted since the 1960s in the United States, Great Britain, Japan, and Germany. Maglev technology was applied in England in the construction of a fully automated, low-speed shuttle in Birmingham, but the line was closed because of maintenance problems. In 1996 funding was approved in Germany for a maglev train linking Berlin and Hamburg, but it was canceled in 2000. In 2004 a maglev line linking Shanghai's financial district with its airport began commercial operation; the train can reach speeds of 268 mph (432 km/h) along its 18.6 mi (30 km) route.

Bibliography: See I. Baldea, New Ways: Tiltrotor Aircraft and Magnetic Levitating Vehicles (1991).

mag·lev / ˈmagˌlev/ • n. [usu. as adj.] a transportation system in which trains glide above a track, supported by magnetic repulsion and propelled by a linear motor: maglev trains.