2. Power supply types

They depend mainly on the type of route chosen:

• This allows the use of power supply conductors either by rails or overhead wires for direct current (metros), or alternating current with high-voltage collection (15 to 25 kV) by overhead wires (high-speed tracks);

• alternatively, as is currently the case with Maglev-type systems, with inductors installed and distributed along the track, via substations, cables, windings and short armatures on board the vehicles; this also allows, by means of an air-gap transformer effect (see box), non-contact power supply to vehicles carrying armature windings and auxiliaries. In this case, the track is sectioned according to the length between substations and the number of vehicles simultaneously on track. This is currently the case for the Transrapid and the Japanese Maglev,...