Gantry crane is a variant of bridge crane. In the port, it is mainly used for the loading and unloading operations of outdoor cargo yards, material yards and bulk cargoes. Its metal structure is like a door-shaped frame, two legs are installed under the main beam, and it can walk directly on the ground track. Both ends of the main beam can have overhanging cantilever beams. The gantry crane has the characteristics of high site utilization rate, large operating range, wide adaptability and strong versatility, and is widely used in the port cargo yard.