One unusual feature of the ICTS cars is that they are driven by linear induction motors: instead of using conventional motors to turn the wheels, they push themselves along the route using alternating flat magnets reacting with the distinctive di-magnetic aluminum metal plate that runs down the centre of the tracks. This system requires very few moving parts and therefore leads to lower maintenance costs. When the car motors are accelerating, they actually lift the car off the track an extremely small distance, repelling against the aluminum plate. This micro-lifting prevents the truck wheels from making a solid electrical contact with the track. Instead of using the conventional method, in which motive power is supplied by a single third rail, with return current travelling through the running rails, a separate positive and negative power rail are provided on one side of the track. With respect to the accelerating trucks and the micro-lifting, the truck wheels have a somewhat larger flange than normal in order to keep the car inline on the track during the micro-lifting. The linear induction motors also allow the cars to climb steeper grades than would be possible with traditional subway technology since wheel slip is not an issue.