This locomotive was built by Andrew Barclay in 1914 as the first of five engines for the Royal Naval Dockyard at Rosyth on the Firth of Forth.
The Admiralty had decided to site a naval base and dockyard in Rosyth in 1903 to strengthen its presence along the eastern seaboard of Great Britain due to a naval arms race with Germany. The government purchased the land, and the town of Rosyth was planned as a Garden City to house the workers. The tidal basin and three graving docks were built by Easton, Gibb and Son Ltd between 1909 and 1916 and the Rosyth Fuel Depot was completed in 1919.
The 1914 built locomotive was therefore ready before the dockyard and it was transferred to the Royal Naval Dockyard at Pembroke Dock. It worked there until 1955 when its boiler was condemned.
Following being fitted with a new boiler by Andrew Barclay the locomotive was deployed at RAF St Athan in the Vale of Glamorgan. The locomotive was only used as a back up to diesel power and in 1972 it was offered for sale.
It was then purchased in 1973 for the Railway Club of Wales.
It was restored to steam in 1985 but there was no where to run it. It was then moved to the Swansea Maritime & Industrial Museum where it steamed on a number of occasions.
The Railway Club of Wales moved to the Gwili Railway in 1987 in order to have an opportunity to steam the locomotive on a more frequent basis.. The locomotive was fitted with Vacuum brake gear which enable it to haul passenger trains in 1991.
Later the locomotive moved to the Swansea Vale Railway and then in 2003 to the Teifi Valley Railway where it has remained in store until 2012. It was returned to steam again in 2014.
In 2016 the locomotive was donated by the Railway Club of Wales (RCoW) to the Pontypool and Blaenavon Railway.
The locomotive is currently operational.