The Taff Vale Railway (TVR) O1 class was a class consisting of fourteen 0-6-2T steam tank locomotives, designed by Tom Hurry Riches, which were introduced to the TVR during the period 1894-1897. Locomotive No. 28 is the last surviving Welsh-built standard gauge locomotive. It began its TVR career working the mineral and coal trains from collieries to port. 

Absorbed into the GWR fleet, No. 28 was renumbered No. 450, and given a GWR-style cover over its safety valve, its external design was unchanged. It was withdrawn from service on 30 October 1926 but was found to be in good mechanical condition and sold to the Government in 1927, for use on the Woolmer Military Instructional Railway, later called the Longmoor Military Railway. The engine was named "Gordon", after the General of Khartoum, and was kept in immaculate condition in Hampshire

The Second World War broke out and No. 28 was renumbered W.D. 205, then W.D. 70205, before becoming surplus again and put into storage. It was then sold in 1947 to the National Coal Board and used at their Hetton colliery railway. It was renumbered No. 67, though still retaining the "Gordon" nameplates. It received a major overhaul in 1955, but by 1959 it needed boiler repairs and was withdrawn from service in 1960.

Following requests to NCB that it should be saved, locomotive 28 was successfully presented to British Railways for preservation in 1962. It is now part of the National Collection. The rest of its classmates were unfortunately scrapped.