Page "Transrapid" Paragraph 8

The super-speed Transrapid maglev system has no wheels, no axles, no gear transmissions, no steel rails, and no overhead electrical pantographs.

The maglev vehicles do not roll on wheels ; rather, they hover above the track guideway, using the attractive magnetic force between two linear arrays of electromagnetic coils — one side of the coil on the vehicle, the other side in the track guideway — which function together as a magnetic dipole.

During levitation and travelling operation, the Transrapid maglev vehicle floats on a frictionless magnetic cushion with no physical contact whatsoever to the track guideway.

On-board vehicle electronic systems measure the dipole gap distance 100, 000 times per second, to guarantee the clearance between the coils attached to the underside of the guideway and the magnetic portion of the vehicle wrapped around the guideway edges.

With this precise, constantly updated electronic control, the dipole gap remains nominally constant at 10 mm ( 0. 39 inches ).

When levitated, the maglev vehicle has about 15 centimetres ( 5. 91 inches ) of clearance above the guideway surface.