No. 4277 was built at the GWR's Swindon Works in 1920, Works No. 2857. It was painted in unlined green livery with "Great Western" on the tank sides. From 1934 a round GWR logo replaced the lettering, and this in turn was replaced in 1942 by the letters "G W R". In 1948 the locomotive passed into British Railways (BR) ownership and was given the power classification 7F. In BR ownership the livery was unlined black. It spent most of its working life in South Wales on freight trains and was withdrawn in 1964 from Aberbeeg Shed (BR shed code 86H) after 44 years of service.