Photo courtesy Railway Technical Research Institute
Traveling at speeds of up to 310 mph (500 kph), maglev trains could begin connecting distant cities in a few years.
 

 

 

 

 

 

 

 

Thought of as a possible alternative to airplanes, maglev trains are powered by electromagnets and are carefully controlled by computers. Maglev is short for magnetic levitation, and these trains float over a guide way using  magnets instead of steel wheel and track trains.

Electromagnetic Propulsion
The basic principle behind electromagnetic propulsion is that  opposite poles attract and like poles repel each other.  Electromagnets attract metal objects, but the magnetic pull is temporary.

The simple idea behind a maglev train rail system has three components:

  • 1. A large electrical power source
  • 2. Metal coils lining a guide way or track
  • 3. Large guidance magnets attached to the underside of the train

Maglev trains do not have an "engine". Instead the magnetic field created by the electrified coils in the guide way walls and the track combine to propel the train.

Photos courtesy Railway Technical Research Institute
Above is an image of the guide way for the Yamanashi maglev test line in Japan.

Below is an illustration that shows how the guide way works.
 

 

 

The guide way is a magnetized coil running along the track which  repels the large magnets on the train's undercarriage.  This causes the train to levitate between 0.39 and 3.93 inches (1 to 10 cm) above the guide way.

Once the train is levitates an alternating current powers the  coils within the guide way walls create magnetic fields that pull and push the train along the guide way. It is the change in polarity that 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. In comparison, a Boeing-777 commercial airplane used for long-range flights can reach a top speed of about 490 mph (789 kph). Developers say that maglev trains will eventually link cities that are up to 1,000 miles (1,609 km) apart. At 310 mph, you could travel from Paris to Rome in just over two hours.

Developing Maglev Technology

Germany and Japan are both developing maglev train technology, and testing prototypes of  trains.

They do have differences though. In Germany, engineers have developed an electromagnetic suspension (EMS) system (very similar to Maglev), called Transrapid which is the first Maglev train for commercial use.  When this system is completed, it should take about an hour to get from Hamburg to Berlin.

Japanese engineers use an electrodynamics suspension (EDS) system (also similar to Maglev), which is based on the repelling force of magnets.

The key difference between Japanese and German maglev trains is that the Japanese trains use super-cooled, superconducting electromagnets which saves energy.

The estimated costs for building a maglev train system in the United States range from $10 million to $30 million per mile, so even though there is interest, it's been difficult to raise funds.