A self propelled propulsion device suitable for pushing, pulling or articulating other tools or equipment around bends within a pipe. The device comprises a first part and a second part, the first part being coupled to the second part by articulating means. The device also comprises a hydraulic system and a control unit. The hydraulic system is operable to returnably separate the first and second part of the device from each other. The hydraulic system further comprises a plurality of pipeline engaging means positioned along an exterior surface of the device which are operable by the hydraulic system to be engagable with the interior surface of the pipeline. The control unit is in communication with the hydraulic system to control the movement of the pipeline engaging means and the first and second parts such that the device is moveable within the pipeline.