This locomotive is an early 50hp Hunslet underground coal mining locomotive (Builder's number 3510 of 1947, although 3512 has also been suggested). It was used at Thorne Colliery in South Yorkshire. Purchased from Amalgameted Construction of Barnsley, it arrived at Porthmadog ( WHR(P) ) in September 1990. Since that time, considerable overhaul work has been done and by 2002 it was operable, although the rebuild was incomplete at that stage.
See The Welsh Highland site for more information.