How about the lifting trolley of launching gantry?

Lifting trolley is made up of longitudinal moving gearbox, transverse girder and rail, transverse moving trolley, winch, movable and fixed pulley group, and hanging beam.

Lifting trolley is the lifting system of launching gantry, it is divided as two layers just like an overhead crane, bottom longitudinal mechanism allows lifting trolley to move longitudinally along rails on main girder; upper transverse moving mechanism allows trolley to move transversely with pre-cast girders; winch could lift and lower the pre-cast girder. Above 3 parts and trolley steel structure constitute a complete set to finish lifting pre-cast girder, moving forward with pre-cast girder, lowering the pre-cast girder and installing boundary pre-cast girder; at the same time it plays a role put small articles onto front abutment.