Single-Connection McCoy Graphite Lubricator for Low-Pressure, Mallet-Type Steam Locomotives, July 1916

Canadian-American inventor Elijah McCoy developed a mechanical lubricator to oil slide valves on steam locomotives. McCoy's device automatically supplied measured amounts of oil to valves, reducing the need for crews to lubricate them manually. This updated version from 1916 was designed for Mallet compound steam locomotives, which used steam twice -- in high- and low-pressure cylinders.