Gantry Crane Lifting mechanism, trolley operating mechanism and bridge structure, and bridge crane basically the same. Because of the large span, the crane operating mechanism adopts the driving mode separately, which prevents the crane from producing a skew operation and increases the resistance, even accidents. Gantry Crane's lifting trolley is running on the bridge frame, and some crane trolley is an arm-frame crane. The legs on both sides of the bridge are usually rigid legs; When the span is more than 30 meters, it is usually a rigid leg while the other side is connected by the ball hinge and the bridge frame, so that the door frame becomes a stationary system, in this way, the additional stress caused by lateral thrust can be avoided under external load, and the longitudinal temperature of the bridge can be compensated by the large wind area of the gantry crane, which is equipped with a measuring instrument and a crane rail clamp connected with the running mechanism in order to prevent sliding or overturning under the action of strong wind. The bridge can be either ends without a cantilever or a cantilever at one end and a cantilever at both ends to enlarge the operating range. The half gantry crane has a leg at one end, and the other end has no leg, and runs directly on the platform.