The overhead crane is settled at a truss cross onto elevated traveling rail pair. The truss can make one-dimension travel on the railway and the trolley can make transverse travel within the railway space. The trolley is equipped with primary cord roller, secondary cord roller, motor and braking device, etc., to lift up/down or stop the primary & secondary lifting hooks or move trolley in transverse direction. This kind of crane is widely applied to move loads or assemble machines at factories or warehouses