Ruston & Hornsby Ltd, of Lincoln, was formed as the result of the merger between Ruston, Proctor & Co. Ltd and Richard Hornsby & Sons Ltd on September 11, 1918 and their first narrow gauge diesel locomotive left the works on September 1, 1931. In the summer of 1932, production was moved to the larger Boultham Works, where the firm were eventually to become Britain’s largest builder of diesel locomotives, with over 6,500 being built by the time production ceased in 1969.