The invention discloses an automatic running rail car. The rail car comprises a driving device, a driven wheel assembly and a frame, wherein the frame is provided with a first cross beam, a second cross beam, two longitudinal beams, a rechargeable battery pack and inverter and a hydraulic system and control system box. The rechargeable battery pack and inverter and the hydraulic system and controlsystem box are arranged on the two longitudinal beams of the rail car. The rechargeable battery pack and inverter provides power for an oil pump and control systems, and an oil tank, the oil pump, ahydraulic control system and an automatic control system are arranged in the hydraulic system and control system box. The rail car bears various railway maintenance machines, can quickly and freely move to a sleeper replacement site back and forth, and is simple in structure, convenient to operate and easy to automatically control.