BR Class 20 No. D8158 in BR green with headcode box and small yellow panel.
The British Railways Board's 1955 modernisation plan called for a change to alternative forms of traction and manufacturers were asked to produce trial or small initial builds for evaluation. English Electric submitted an existing design based on an export model for a 1000 b.h.p diesel and 20 were built as a pilot scheme for assessment.
The first batch was built in 1957 and the diesels were assigned to work from Devon's Road depot, East London. The design was a success from the start and by 1962 a total of 127 had been built. Following assessment of all the Type 1 diesels, BRB placed a further order increasing the total to 228 by 1968 and the design became the BR standard for 1000 b.h.p diesel locomotives. With the introduction of the TOPS code system in 1968 the diesels were designated Class 20 and renumbered 20 001 to 20 228.
The diesels were principally designed for freight work but also saw service on summer passenger trains (no train heating for winter'). The Class 20's worked over the Eastern, London, Midland and Scottish regions. The only drawback the diesel has is one cab, unlike modern designs that have a cab at each end. BR resolved this problem by operating the diesels as pairs, nose to nose, and with the combined power of 2000 b.h.p they were able to haul the heavier block freight trains.
BR's decision to switch to Type 5 and in particular Class 60 diesels in the late 1980’s started a gradual withdrawal of the fleet with just 28 left by 1994. A tribute to the design is that after 45 years the Class is still in service with DRS on mainline duties and at least 28 of the class are now preserved.
