Basically, it's the principle of using magnets
There are three components to this system:
1) A large electrical power source
2) Metal coils lining a guideway or track
3) Large guidance magnets attached to the underside of the train
The big difference between regular trains and maglev trains is that mag lev trains do not use an engine.
Also, maglev trains do not use fossil fuels. Instead, they are propelled by a magnetic field created by electrified coils - this combined with guideway walls on the track creates movement.
Maglev trains technically "float" over air which eliminates friction and increases levels of speed - as high as 310 mph or 510 kph