Class 37 – D6700

Built by English Electric at Vulcan Foundry in 1959, D6700 was the very first Class 37 diesel-electric locomotive to be constructed, entering service on 2nd December 1960 and originally allocated to Stratford Depot in East London. Measuring nearly 19 metres in length and weighing 107 tonnes, it features a Co‑Co wheel arrangement, a top speed of around 90 mph, and formed part of British Rail’s 1955 Modernisation Plan to phase out steam in favour of diesel and electric traction.

D6700 was one of over 300 Class 37s built, which went on to become a mainstay of the British Railways network, working across the country on both passenger and freight services. The class earned a strong reputation for reliability and longevity, with a few examples still in mainline use today. D6700 itself was later converted to a Class 37/3 and eventually painted in BR green with small yellow warning panels, restoring the look it first wore during its early years.

Withdrawn from traffic in the early 2000s, D6700 was donated by EWS to the National Railway Museum in July 2001, where it became part of the National Collection. Under the care of the museum’s volunteer diesel team, the locomotive was kept in good condition and continued to receive maintenance.

In a significant step for heritage diesel traction, a new loan agreement between the NRM and the Heavy Tractor Group (HTG) allowed D6700 to return to working order on the Great Central Railway. Final mechanical work and repainting were carried out by HTG’s industry partner, Loram UK, ahead of its return to regular operational use. D6700 continues to appear at diesel galas and on scheduled services as part of the GCR’s running fleet.

D6700 recently featured at the Greatest Gathering, Railway 200 celebrations, as a fine representation of a living, working example of British Rail’s transition to diesel—and a proud ambassador for the National Collection on the main line of preservation.