While maglev transportation was first proposed more than a century ago, the first publicly used maglev trains will not debut until at least next year in Shanghai, China, using the train developed by a German company. Germany and Japan are both developing maglev train technology and are currently testing their prototypes.

German engineers are building an electromagnetic suspension (EMS) system, called Transrapid, in which the train's bottom is wrapped around a steel rail. Electromagnets attached to the train's bottom are directed up toward the rail, which levitates the train about one-third of an inch above the rail keep the train levitated even when it's not moving. Other guidance magnets embedded in the train's body keep it stable during travel. Germany has demonstrated that the Transrapid maglev train can reach 300 mph with people onboard.

Japanese engineers are developing a competing version of maglev trains that use an electrodynamic suspension (EDS) system based on the repelling force of magnets.

Photo ofJapan's MLX01 experimental maglev train

The key difference between Japanese and German maglev trains is that the Japanese trains use super-cooled, superconducting electromagnets, whereas the German's EMS system uses standard electromagnets. The kind of electromagnet used in the Japanese trains can conduct electricity even after the power supply has been shut off. By chilling the coils at frigid temperatures, Japan's system saves energy.

Another difference between the systems is that the Japanese trains levitate nearly 4 inches above the rail. One possible drawback in using the EDS system is that maglev trains must roll on rubber tires until they reach a liftoff speed of about 62 mph. Japanese engineers say the wheels are an advantage if a power failure caused a shutdown of the system. Germany's Transrapid train is equipped with an emergency battery power supply.

Despite U.S. interest in maglev trains over the past few decades, the expense of building a maglev transportation system has been discouraging. Estimated costs for building a maglev train system in the United States range from $10 million to $30 million per mile. However, the development of room temperature superconducting supermagnets could lower the costs of such a system. Room temperature superconductors would be able to generate equally fast speeds with less energy.

An image of the rail for the Yamanashi maglev test line in Japan.

An illustration that shows how the guideway works.