DRIVE SYSTEM FOR A PANTOGRAPH, AND METHOD FOR RAISING OR LOWERING

A drive system for raising or lowering a sliding piece of a current collector for rail vehicles. The sliding piece is disposed on a positioning device of the current collector, and the sliding piece is configured to be brought into contact with an overhead line using contact pressure. The drive system includes a bellows drive which is actuated by compressed air to actuate the positioning device, and a pneumatic control unit having a control valve for supplying or withdrawing compressed air to/from the bellows drive. The drive system includes a detection line and a lowering valve for venting the bellows drive when pressure drops in the detection line, the lowering valve being a 3/2-way valve disposed in a pneumatic supply line between the control valve and the bellows drive.