BR Class 37

BR Class 37
Steve Jones · CC BY 2.0 · source
Name	British Rail Class 37
Powertype	Diesel-electric
Builder	English Electric
Builddate	1960–1965
Totalproduction	309

BR Class 37 is a diesel-electric locomotive introduced in the early 1960s for British railways, built by English Electric to replace steam traction and augment diesel fleets. It served passenger, freight, and departmental duties across British Railways regions, interacting with companies and locations such as British Rail Engineering Limited, London Midland Region, Eastern Region, Scottish Region, and major hubs like Crewe and Swindon Works. Over decades it worked on routes linked to West Coast Main Line, East Coast Main Line, Settle–Carlisle line, and freight flows to ports such as Southampton and Felixstowe.

Design and Development

The Class 37 arose from specifications by British Railways Board and design work at English Electric's workshops in Vulcan Foundry, influenced by earlier designs like the British Rail Class 40 and British Rail Class 45. Key stakeholders included engineers from British Transport Commission and industrial partners such as Sulzer and Ruston & Hornsby. Prototype trials involved runs between Doncaster Works and King's Cross and evaluations against contemporaries like Metropolitan-Vickers units. Design decisions balanced power output, axle load for routes including the West Highland Line, and compatibility with depot facilities at Toton TMD and Haymarket depot.

Technical Specifications

The locomotives used an English Electric 12CSVT derivative prime mover coupled to English Electric traction alternators and DC traction motors; related technologies had precedents in Scottish Aviation projects. The Bo-Bo or Co-Co wheel arrangements were engineered to meet route availability constraints affecting lines such as the Settle–Carlisle line and Waverley Route. Braking systems complied with standards applied on stock serving InterCity services and freight to terminals like Dover. Electrical control equipment reflected developments in power electronics and relay logic found in contemporaneous rolling stock at Crewe Works and Doncaster Works.

Service History

Deployment began in the 1960s with allocations across British Rail regions; Class 37s operated express parcels on corridors to Euston, worked coal and mineral trains to Immingham, and handled passenger diagrams on secondary routes such as the Cumbrian Coast Line and services to Aberdeen. The type saw extensive use during reorganisations by entities like Regional Railways and later interactions with operators including National Express and Arriva subsidiaries. Notable operational episodes include heavy freight workings during the oil crisis and adaptation for nuclear flask movements between Winfrith and Sellafield. Over time, the fleet faced cascade and withdrawal as newer classes such as British Rail Class 47 and British Rail Class 66 entered service; nevertheless retained members continued in departmental roles for Network Rail and industrial operators like EWS.

Variants and Subclasses

Throughout service the design spawned subclasses adapted by workshops at Doncaster Works and Haymarket depot into forms with varied gearing, headcode layouts, and train heating arrangements; these were coded into sub-classes by allocations managers in British Rail records. Specialised conversions included departmental variants for test trains linked to Railtrack projects, and bracketed modifications for sleeved operations on routes to Holyhead and Fishguard Harbour. Other conversions paralleled practices seen across fleets like the British Rail Class 56 remanufactures carried out by industrial firms such as Brush Traction.

Preservation and Heritage Operations

Numerous examples entered the heritage railway scene with custodians including the North Yorkshire Moors Railway, Great Central Railway (Nottingham), West Somerset Railway, and museums like the National Railway Museum. Preservation groups and trusts have performed overhauls at facilities such as Rothwell depot and workshops at Barrow Hill Roundhouse, enabling mainline-certified excursions under the auspices of bodies like Rail Safety and Standards Board protocols and operators including Vintage Trains and UK Railtours. Preserved units appear in galas alongside types such as BR Standard Class 7 steam locomotives and Class 47 diesels, supporting interpretation of diesel traction history for visitors from London, Glasgow, Cardiff, and Belfast.

Category:Diesel-electric locomotives Category:English Electric locomotives