Abstract: The invention relates to a drive system for driving movement of a patient support device across a floor, comprising a base having a front side facing the patient support device, first and second drive wheels arranged on said base said wheels being rotatable around first and second respective wheel axles substantially parallel to the floor and rotatable around first and second respective swivel axles substantially perpendicular to the floor, wherein the first and second swivel axles are spaced apart from each other when projected onto the front side and arranged at fixed positions on the base, wherein the drive wheels are rotatable around their swivel axles between a first orientation for forward movement, and a second orientation for transverse movement, wherein in the second orientation the first and second drive wheels are positioned at substantially different distances from the front side of the base.