Abstract: A bogie is attached to a three point hitch of a tractor and serves to control the up and down movement of a scraper blade. The bogie comprises an articulated frame having a pair of spaced side rails each connected to a separate lower link of the hitch. An intermediate arm is supported by the side rails and has means for connection to the upper link of the hitch. A castor is mounted for swivelling in a wheel housing and is raised and lowered by means of an hydraulic actuator.