FRANKFURT, Germany - Using magnets to hold trains in the air so they can travel at speeds comparable to planes has long been a goal for making long-distance travel enjoyable.

But because maglev trains can't use the hundreds of thousands of miles of traditional rail track that crisscross the world, building such a system costs billions of dollars in research, testing and construction for both the trains and their special rails.

Magnetic-levitation works by suspending, propelling and guiding vehicles with electromagnetic force.

Because there is no actual contact with the rails, and hence no friction, vehicles can move much faster than a traditional train rolling along a fixed track under its own propulsion.

While countries like Japan, with its Shinkansen bullet train, and France, which has its TGV system, along with Germany operate high-speed rail service, only China has a commercially operating maglev service.

The Transrapid line, built with German technology from ThyssenKrupp AG and Siemens AG, links Shanghai's Pudong International Airport with the city's financial district. It covers nearly 20 miles at up to 270 mph.

The Chinese government said earlier that work will begin this year on a second maglev line linking Shanghai and the resort city of Hangzhou, a $4.4-billion, high-speed line.

The new line, due to launch by 2010, will cut travel time from Shanghai to Hangzhou to a half-hour from the current two hours.

Friday's crash in Germany was blamed on human error and not the technology.

Rudolf Schwarz, a spokesman for IABG, which oversees the test track where the crash occurred, said the train struck a maintenance cart at about 125 mph. The impact crushed and peeled back the train's roof.

The crash was believed to be the first time that a maglev crashed with fatal results, and research is expected to continue to refine the concept.

In Japan's Yamanashi prefecture, JR-Maglev MLX01 test trains have gone as fast as 361 mph by using superconducting magnets and electro-dynamic suspensions, or EDS.

The Transrapid, however, uses conventional electromagnets and an electro-magnetic suspension, or EMS.