Abstract: A controllable, motor-driven undercarriage which comprises a first frame having non-driven castors and a second frame carrying driving wheels. The second frame can be turned relative to the first frame for changing the direction of the driving wheels and can be locked in any position relative to the first frame. The second frame is a two-armed lever which is pivotable about a central axis and at either end carries a driving wheel which is provided with an independently controllable driving means. The independently controllable driving-wheels are used both for the driving and steering of the undercarriage and for swinging the lever between different locked positions.