This gantry crane is mainly used for bridge construction and has a low operating speed. It is composed of a gantry platform, a trolley with winch, a trolley driving mechanism, a driver's cabin and an electrical control system. The portal is a truss structure, the advantages of which are lightweight construction and strong wind resistance. Including main beam, upper end beam, outriggers, lower end beam, pedestrian cart, walking platform railing, etc. The main beam has a triangular truss structure with tracks laid on it, allowing the cart to move laterally towards the main beam. The legs are supplied in box or steel tube shape. The trolley is equipped with a winch, which is compact in size and light in weight.