Gantry crane is an overhead type crane which horizontal bridge structure is installed over the two landing legs to form portal crane. This crane on the ground runs on the track. It is also known as the gantry crane or portal crane, commonly known as portal jib crane. The application of gantry cranes significantly reduces the labor intensity of the loading men, improves the operating conditions and he production capacity of loading and unloading operation, and makes a tremendous rise in labor productivity. It is key lifting equipment to packaging construction quality and beneficial result. Gantry cranes are widely applied to many industries such as the ground assembly of electric field equipment, coordination of manufacturing and pressing of the equipment, prefabricating of cement framework and lifting objects,etc. Rail gantry cranefor load or unload trains and cars in railway goods yard; hoisting vessel segment in shipyard; lifting the gate in hydropower station; container loading and unloading in port and pier; lifting and handling bulky items in inside factory; field operation in the construction site and piling up wood in lumber storage yard.
 
The structure of gantry cranes, on the whole, its composition mainly divided into three parts: mechanical part, structure division and electrical part. Specifically, gantry crane consist mainly of portal-framed structure, load-trolley, large cart parts, electrical fixtures and operator cabin.
 
Hoisting mechanism, trolley travel mechanism and girders of gantry cranes is basically the same as the bridge crane. Because of the large span, individual drives are adopted for traveling mechanism on each end of the crane by gantry crane manufacturer to prevent deviating running with additional resistance, or even an accident. Crane carriage of gantry crane is running on the bridge shelves. Some lifting trolley is a jib type crane. The landing legs of both sides of the bridge are generally rigid leg. But if the span is more than 30 meters, often one should be rigid, and the other should be flexible leg by connecting spherical hinge and crane span structure to make the gantry become a statically determinate system. This can avoid causing additional stress from lateral thrust under external loadings and also can compensate longitudinal temperature deformation of crane span structure. Gantry cranes have a larger windward area, in order to prevent sliding or turnover with the action of strong wind, it is equipped with wind meter crane rail clamp which is interlocked with operating organization. The bridge is free of cantilever at both ends or has a cantilever at one end or has two cantilevers at both ends with expanding the working scope.