A system includes a docking station, for location on a surface to be worked, and a self-propelled working tool. The station has a primary transmission part. The tool has a body, a surface-engaging wheel, and a secondary transmission part. The station and the tool can establish contact with each other and the tool can drive up to the station and achieve a docking position wherein the transmission parts contact and cooperate. In one aspect, the secondary transmission part is located on an upper portion of the body. In another aspect, the station includes a part spaced upwardly away from the surface, with the primary transmission part located thereon and directed downwardly. In another aspect, a portion of the body is located beneath a portion of the part upon which the primary part is located and the wheel remains engaged with the surface when in the docking position.