It mainly consists of hydraulic loading arm system, drawing system and central control system. The hydraulic loading arm system is one of the key systems, and it composes of elevating device, stretching device, hydraulic station and a movable car. The elevating device helps to push the elevating pipe close to the bottom of the railcar, and it is operated hydraulically. The drawing device is made up of transmission device, a little movable car, chain transmission device, tension device and an idler roller. The drawing device helps guide the railcar moving forward and backward in order to roughly fit the opening of the oil tank to the loading arm.