Abstract: A pipeline inspection vehicle has at least one resilient driving cup mounted around the body of the vehicle so as to contact the interior wall of the vehicle and thus provide a pressure differential across the driving cup which will propel the vehicle along the pipeline. An annular array of ducts extends through the body of the vehicle to by-pass fluid through the driving cup, each duct being provided with a control valve for regulating the flow of fluid through the duct. A control arrangement is provided for opening and closing the control valves in dependence on the speed of the vehicle, thereby to adjust the speed of the vehicle in accordance with a desired speed.