Double girder gantry cranes adopt Q345B steel material for steel structure and use legs to support the bridge, trolley, and hoist. They can travel on single or double rails on the ground. The double girder gantry crane is widely used for indoor and outdoor applications. Gantry cranes have a strong box design, less distortion and automatic welding. The gantry crane is composed with main beams, end beams, cantilever, front and rear legs, outrigger, trolley traveling mechanism, cab and electric control system, crane hook, drum, cable reel, wheels, etc. The double girder gantry cranes features a box-shape structure, and the leg is available with type A and type U. The trolley is assembled with motor, reducer, brake, trolley frame, drum, crane hook, pulley, rain cover and other part.