A gantry crane is provided which is equipped with standard wheels having rubber tires for free maneuverability on a road surface, such as asphalt, gravel, pavement, etc., wherein the crane is additionally equipped with a plurality of railwheels to provide auxiliary support one or more rails in the loading area. In a first mode, the crane is supported only on rubber tires for driving on a paved surface, and in other modes, one or both sides of the crane are supported via the railwheels on rails. In an embodiment, a railwheel may be securely mounted coaxially to the steel rim of the respective steel wheels, forming a dual or combination wheel. The railwheels are sized relative to the tires of the standard wheels so that the railwheel does not impair non-rail loading operations, i.e., the railwheel vertically clears the ground even when the tires deflect as the crane is fully loaded. Railwheels may be provided on one or both sides of the crane. Each of the railwheel has dual flanges to maintain rollable positioning of the railwheel on the rail, enabling the crane to be driven in a self-steering manner.