The magnetized coil running along the track, called a guideway, repels the large magnets on the train's undercarriage, allowing the train to levitate between 0.39 and 3.93 inches (1 to 10 centimeters) above the guideway [source: Boslaugh]. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway. The electric current supplied to the coils in the guideway walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.
Maglev trains float on a cushion of air, eliminating friction. This lack of friction and the trains' aerodynamic designs allow these trains to reach unprecedented ground transportation speeds of more than 310 mph (500 kph), or twice as fast as Amtrak's fastest commuter train [source: Boslaugh]. In comparison, a Boeing-777 commercial airplane used for long-range flights can reach a top speed of about 562 mph (905 kph). Developers say that maglev trains will eventually link cities that are up to 1,000 miles (1,609 kilometers) apart. At 310 mph, you could travel from Paris to Rome in just over two hours.
Some maglev trains are capable of even greater speeds. In October 2016, a Japan Railway maglev bullet train blazed all the way to 374 mph (601 kph) during a short run. Those kinds of speeds give engineers hope that the technology will prove useful for routes that are hundreds of miles long.
Germany and Japan both have developed maglev train technology, and tested prototypes of their trains. Although based on similar concepts, the German and Japanese trains have distinct differences. In Germany, engineers developed an electromagnetic suspension (EMS) system, called Transrapid. In this system, the bottom of the train wraps around a steel guideway. Electromagnets attached to the train's undercarriage are directed up toward the guideway, which levitates the train about 1/3 of an inch (1 centimeter) above the guideway and keeps the train levitated even when it's not moving. Other guidance magnets embedded in the train's body keep it stable during travel. Germany demonstrated that the Transrapid maglev train can reach 300 mph with people onboard. However, after an accident in 2006 (see sidebar) and huge cost overruns on a proposed Munich Central Station-to-airport route, plans to build a maglev train in Germany were scrapped in 2008 [source: DW]. Since then, Asia has become the hub for maglev activity.