Class 25 D7612

D7612, later being designated as a Class 25, was built at British Railways' Derby works and first allocated to Glasgow Eastfield in April, 1966. It was one of thirteen allocated to the Scottish Region fitted with single line token catcher recesses in the cab sides under the driver's windows. However, it moved within a year  to Derby in September, 1967, then Nottingham and Birmingham until allocated to Bescot in 1973. It worked from Bescot until being placed into store (unserviceable) in April, 1982 at Derby with power unit problems. It received the power unit from 25274 and was restored to service at Bescot in May, 1982.

25262, as it had become by then, went back north in 1985 and was allocated to Carlisle Kingmoor. It was renumbered 25901 in December, 1985 as part of a sub class of twelve locomotives for use on the industrial minerals and chemical sectors of BR. All of the Class 25s were withdrawn in 1987 with 25901 being officially withdrawn on 16th March, 1987. However, the locomotive worked on past this date on trip work and is thought to be the last Class 25 to work a normal BR service towards the end of April, 1987.

It was purchased by the Harry Needle Railroad Company and, in September, 1989 moved to the East Lancashire Railway. It was later sold on to a small group of members on that railway and sold on again to South Devon Diesel Traction in 1999 and moved to the South Devon Railway.

It is visiting the GCR for the May, 2013 Diesel Gala and arrived on 15th May, 2013. It left the GCR on 26th September, 2013.