A type double girder gantry crane with hook is suitable for open storage, along railway operations for general handling and lifting work. A type door frame structure, on the top of it there is a saddle structure , reasonable force, and it is the most widely used double girder gantry crane. According to their structure, can be divided into boxes-MG, rated lifting weight is 5~320t and reduced wind resistance design of truss structure of MGH, rated capacity is 5~50T.