Originally designated Type 2, later to become Class 24 in the TOPS system, a total of 151 of these diesel-electric locomotives were built powered by the 6LDA28-A Sulzer engine, giving an output of 1160bhp. The majority was built at BR Derby, although some were constructed at Crewe and Darlington. In addition, Beyer Peacock, Gorton, who was privately contracted, built a further batch. The consultant designers for the Type 2 were Wilkes & Ashmore, with the first of the class, D5000, being completed at Derby in July 1958. This was subsequently put on display that month at Marylebone Station, London - this locomotive was alomost selected for the National Railway Museum, York but was ultimately scrapped. Although intended for use on the London Midland region, on their introduction they went to the Southern Region to deputize for Type 3 'Crompton' diesels that were late in delivery. By the time the entire Type 2 fleet was in traffic, they could be found operating on all regions with the exception of the Western. With a life span of 28 years these small, yet versatile, locomotives gave excellent service in all manner of roles in branch and main line duties either singly or working in multiple. The Class 24's began to be phased out of BR capital stock in the late 1960's, with the final locomotive being withdrawn in 1981. Several locomotives were retained after this for carriage pre-heating duties.