British Rail Class 21 (NBL)

The British Rail Class 21 was a class of 58 Type 2 diesel-electric locomotives built by the North British Locomotive Company in Glasgow for British Railways between 1958 and 1960 and numbered D6100 to D6157. They came out of the Modernisation Plan's dieselisation pilot scheme, which began with an order for ten 1,000 horsepower locomotives for evaluation, alongside six similar locomotives with hydraulic transmission that became the Class 22. Repeat orders brought the total to 58, and the last twenty carried uprated 1,100 horsepower engines. The MAN designed engines, built under licence by the builder, proved unreliable, with coupling, cooling and fire problems, and the fleet moved from the Eastern Region to Scotland in 1960. Twenty were re-engined with Paxman Ventura engines as Class 29, and the rest were withdrawn between December 1967 and August 1968. None survive.