This locomotive was built by Avonside Engine Company in 1914 as a class B3 0-6-0ST.
Between 1906 and 1926 59 locomotives were built to this design. Of these 26 operated on the Mersey Docks & Harbour Board Railway at Liverpool.
Sir John was employed in the coalfields where it was withdrawn from service in the early 1970s whilst based at Mountain Ash Colliery in South Wales.
It has since been preserved on the Gwili Railway.