Abstract: A tractor (20) for unloading a trailer (12) from a railcar (14) is disclosed. The tractor (20) comprises a trigger actuator (34) and a bumper (30). The trigger actuator (34) is fixably mounted to the tractor (20) and remains stationary. The bumper (30) of the tractor (20) may be operated between an extended position and a retracted position. When the bumper (30) is in the extended position and the tractor (20) is adjacent to a stanchion (16), the trigger actuator (34) does not engage the trigger of the stanchion (16). When the bumper (30) is in the retracted position and the tractor (20) is adjacent to the stanchion (16), the trigger actuator (34) engages the trigger (28) of the stanchion (16) to operate the stanchion (16) from the raised position to the lowered position, thereby transferring the trailer (12) from the stanchion (16) to the tractor (20).