The first commercial maglev--or magnetic levitation--train will be built in Shanghai, authorities have announced. The service is expected to cover the 19 miles between the city and its airport in less than 10 minutes by the end of 2003. The building contract between Transrapid International, a consortium led by the companies ThyssenKrupp and Siemens, and the Chinese will be signed in Shanghai today.

Maglev trains are levitated, guided and propelled by electromagnetic forces, and can reach top speeds of more than 500 kilometers per hour (310 miles per hour). They cannot, however, use existing railways, making them very expensive to build. There is no example of a commercial maglev at present, although Germany and Japan have been testing their maglev technologies for decades. The Chinese project, expected to cost about $ 1.2 billion, will set an example for other countries. If all goes well, the authorities there hope to eventually extend maglev service to Hangzhou, 120 miles away, or even Peking, almost 800 miles from Shanghai.

In the U.S., maglev trains have been considered, but never built. Last week, though, the Transportation Department selected two projects, a link between Baltimore and Washington and one between Pittsburgh and its eastern suburbs, to be considered for a federal government maglev pilot project.