Heavy duty electric overhead travelling crane in steel plant demands a high working level and perfect quality. It is made up of trolley, bridge girder, end carriage, operator’s cabin, crane moving system and electrical system. Below are simple introductions on one of its parts: end carriage.
End carriage shall be fabricated from rolled steel sections or plates, or both, welded together to form a box section with reinforced opening for wheels, etc. If more than two wheels are required, bogies shall be provided or articulated end carriages shall be used. End carriages shall be connected to the girders by large gusset plates & fitted bolts to ensure maximum rigidity. End Carriage shall have ample strength to resist stresses likely to be imposed under worst conditions, including collision with stops.  The extreme ends of the end carriage shall be such that no part of the crane projects beyond the fully compressed buffers.
There shall be a heavy safety lug or strap across the bottom of each carriage near the track wheel and 25 mm above the top of rail to prevent excessive drop in case of breakage of track wheel, axle or carriage. These safety stops shall not interfere with the removal of wheels.
End carriage shall be designed so as to permit easy changing of wheels. Suitable jacking pads at a height of 300 mm from rail level shall be provided on each end carriage for changing the track wheels by jacking up the crane.  Jacking pads shall not interfere with the placement of track wheels.