D7633 was built by Beyer Peacock as a Class 25/3, entering service on 30 October 1965.

Under TOPS the locomotive became 25.283, subsequently becoming 25.904.

D7633 was one of twelve of the remaining Class 25/3 locomotives in 1985 to be designated as Class 25/9.  The intention was they would operate traffic won for the Industrial Minerals Division of Railfreight that included salt for road gritting from the ICI mine at Winsford.

The locos were selected from the available pool of Class 25 locomotives in March 1985 with the expectation of three more years of service before 10,000 running hours since last Works attention would be reached and their maintenance would be concentrated at Carlisle Kingmoor depot.

At that point the expected cascade of motive power on BR as a whole would see them replaced by Class 31 locomotives.

However, the traffic they were designated for was not captured and in due course the sub-class were withdrawn along with the other members.

D7633 was withdrawn on 19 March 1987.

D7633 is preserved at the Dean Forest Railway in two tone green livery with half yellow ends.