British Rail Class 20

The Class 20 originated in the 1955 BR Modernisation Plan and the subsequent 1955 Pilot Scheme, under which BR ordered small batches of competing diesel designs from various manufacturers for evaluation in service. English Electric's submission for the Type A (1,000 hp) requirement was the design that became the Class 20. An initial Pilot Scheme batch of 20 (D8000–D8019) was built at the Vulcan Foundry between 1957 and 1958.

The Pilot Scheme batch was sufficiently successful that BR ordered 108 more in 1958–1962 (D8020–D8127), bringing the Phase 1 batch to 128. After a four-year production gap, BR ordered a further 100 (D8128–D8199 and D8300–D8327) in 1966–1968 to complete the class at 228 locomotives. The Phase 2 batch had revised headcode panels, minor body and cab styling differences, and updated electrical equipment.

The single-cab design was a distinguishing feature. While most British Type 1 specifications envisaged dual-cab locomotives, English Electric argued that a single-cab layout with the engine compartment trailing offered superior forward visibility for the locomotive's intended freight role and could be operated bidirectionally by pairing two locomotives cab-to-cab. This proved to be the universal Class 20 operating practice and one of the class's signature images.

The Class 20 was the most numerous and most successful British Type 1 diesel. The class spread quickly across the BR system from 1957 onwards and by the late 1960s was the standard medium-power freight locomotive on most BR regions. Through the 1970s and 1980s the 20s worked colliery trips, summer Saturday holiday extras, ore trains, china clay traffic, Civil Engineers' work, and trip working everywhere. Their robust simplicity made them favourites with crews.

Withdrawals began on a significant scale from 1986 onwards as the BR sectorisation process and the introduction of newer Type 5 diesels reduced the need for so many older Type 1 freight locomotives. Through the late 1980s and early 1990s the class was progressively stored, withdrawn, and scrapped, with many disposed of via Booth Roe and Vic Berry of Leicester.

However, the class's final chapter was unusually positive. From 1995 the newly-formed Direct Rail Services (founded to operate British Nuclear Fuels' flask trains) acquired a fleet of Class 20s and refurbished them for further service. DRS-operated 20s in nose-to-nose pairs became the standard motive power for nuclear flask trains for two decades. GB Railfreight subsequently acquired further examples for engineering and infrastructure work. In 2026 around thirty Class 20s remain in mainline service.

The signature single-cab Bo-Bo "chopper" body, with the cab at one end and the engine compartment behind it. The locomotive is asymmetric in profile, with the long-nose engine compartment ahead of the cab when running long-end-leading. Most often seen working in nose-to-nose pairs (two locomotives coupled cab-to-cab giving an effective dual-cab unit). Phase 1 examples (D8000–D8127) have the original split headcode disc panels; Phase 2 examples have the revised flat-front headcode boxes. Distinctive raucous engine note when accelerating.

D8000 (later 20050), the first of the class, completed at Vulcan Foundry in June 1957. Withdrawn 1980 and preserved by the National Collection at the National Railway Museum, York.

20001 (originally D8001), the first TOPS-numbered Class 20. Privately preserved.

20007, an early Phase 1 example preserved at the Strathspey Railway.

20020 (originally D8020), preserved at the Bo'ness and Kinneil Railway.

Many later Phase 1 and Phase 2 examples are preserved on heritage railways, and around thirty further examples remain in active mainline service with DRS and GBRf in 2026 (including 20096, 20132, 20142, 20154, 20189, 20227, 20228 and others; the active fleet is fluid and current detail should be consulted from operator pages).

BR (1957–1996): the class was widely distributed across the BR system. Major early allocations were Devons Road (London), Toton (East Midlands), Tinsley (Sheffield), Healey Mills (West Yorkshire), Bescot (West Midlands), Eastfield (Glasgow), Inverness, and the South Wales depots. The Phase 1 batch of 1957–1962 was largely concentrated on the Eastern Region, the Phase 2 batch of 1966–1968 widely across the system. Notable regular workings included Skegness summer Saturday holiday trains, Cornish china clay traffic, Scottish coal and freight, and Toton-based freight workings. The class was also a regular sight on civil engineering and ballast trains nationwide.

Privatisation onwards (1996–present): much of the class passed to Direct Rail Services from 1995 onwards (DRS having been founded specifically to operate nuclear flask trains, with Class 20s in pairs as the principal motive power). GB Railfreight subsequently took over a number for engineering and infrastructure work. In 2026 around thirty Class 20s remain in active mainline service with DRS and GBRf.

BR Brunswick green (1957–1968): the class was outshopped in BR Brunswick green with a small lower-bodyside warning panel.

BR Rail blue (1965–1987): from the mid-1960s the class progressively wore standard BR Rail blue with full yellow ends, the BR-standard livery for diesels.

BR sectorisation (1987–1996): Trainload Construction (light grey), Railfreight Coal (red and grey), Railfreight Petroleum, Civil Engineers (yellow/grey "Dutch"), and Railfreight General Distribution were all carried by the class.

Direct Rail Services (1995–present): DRS Compass blue (the original DRS dark blue with diagonal flash) was carried by all DRS-operated Class 20s for many years, more recently revised to a plain blue. GBRf operated examples have carried GBRf orange-and-blue.

Preservation: preserved examples have appeared in BR Brunswick green, BR Rail blue, BR sector liveries, and DRS blue, all authentic for the class.