As part of the Modernisation Plan in the 1950s, the lightweight, multi-purpose Sulzer Type 2 was introduced. When the initial version proved underpowered, a new variant was built - these later became the Class 24 and Class 25 diesels respectively. 327 Class 25s were built, and became such a common sight on the railways that they were nicknamed "rats" by spotters.

D7628 was built by Beyer Peacock in Manchester as one of the last batch of locos, and entered service at Tinsley in October 1965. After a spell at Wath, she moved to the Midland Region in 1967. By then numbered 25278, this loco was the last of her class to receive a general overhaul, at Derby, in 1981 and was officially withdrawn on 15 March 1987.

Painted in the two-tone green on early examples of the type and named ‘Sybilla’ at the request of its previous owner Jos de Crau, she can be seen in regular use on NYMR.