I served my time on double girders then Monobox single girders with J H Carruthers in East Kilbride Scotland U K I done building in the factory then erecting and repairs throughout the U K great job.
This crane guider design is faulty, the main guide should extend out over the trucks past the rails the wheels run on, and then it can be notched down for the trolley should the bolts shear or fall out the main guide with the load can not drop.
