Abstract: An overhead crane for use in handling critical loads and including a horizontally movable trolley on which is mounted a single failure proof hoist mechanism having alternative or redundant means for supporting the loads if structural failure occurs in the hoist mechanism. The hoist mechanism comprises a rotatable drum, drive means for rotating the drum, an upper sheave block, and a lower sheave block supporting a hook assembly. A pair of wire ropes, each capable of fully supporting the load, are wound around the drum and the upper and lower sheave blocks and function to suspend the lower sheave block and the hook assembly. The hoist mechanism also comprises an equalizer assembly operably connected to the trolley and supporting the ropes in such a manner as to provide means to compensate for any discrepancies in the lengths of the two ropes.