Sockets were used to tighten or remove bolts and associated nuts. The mechanic used a bar inserted through a hole in the top end of the socket or used a large, open-end wrench to turn the socket. A long-handled bar or wrench gave considerable leverage in turning or holding the socket. An "extender" could be slipped onto the bar or wrench handle to give even more leverage.
This tool is part of a collection of hand tools used in the inspection and repair of steam locomotives in the early- to the mid-20th century, roughly 1900-1955. Light repairs on steam locomotives were usually done in roundhouses at the many small locomotive terminals throughout a railroad's system; heavy repairs were done in a large, centralized repair shop serving the whole system (often referred to as the "Back Shop").
