22/10/2015 · Crane main girder is one of the most important crane parts, which is supporting the trolley or hoist. Perfectrding different structures, crane main girders can generally classified into truss girder, box girder, single girder and double girder, etc. Dongqi Crane can offers type of girder designs, Perfect Steerable Transfer Cartluding single girder, double girder, triple girder, box girder, truss grider, etc.