To provide an innovative method based on a new idea for preventing the occurrence of an arc itself unlike the conventional method in which such an arc is simply reduced or lightened at the time when a pantograph is disconnected from a trolley wire in operating an electric car.

The collecting slider of a piece of pantograph is divided into two pieces of sliders that are electrically isolated to each other. An autotransformer is connected between one of the sliders and rails, and a load of an electric car between another one of the sliders and the rails. When these sliders are slidably connected to the trolley wire simultaneously, they are electrically short- circuited by the trolley wire itself. By utilizing this effect, the collecting method of the electric car in operation is structured in such a way that the autotransformer works as a power supply that feeds a load of the electric car directly.