7ton trolley locomotive has two types: 250V and 550V. 

The control system use resistance, IGBT system and frequency control system. The locomotive consists of mechanical part and electrical part. The mechanical part consists of frame, moving and running system, wheel sets, cab(closed, ope), braking device, sanding device, elastic suspension, buffer device and cover plate bracket.

The electric part consists of electric motor, the starting resistance, the driver controller, the current collector, the direct transformer, the lighting lamp. The motor is DC traction motor which has large starting torque, equip power characteristics, the motor meets transport requirements when over loading in slow speed, reducing loading for high speed.