The BR Class 50 is a 2,700bhp diesel-electric locomotive built by English Electric at their Vulcan Foundry at Newtown-le-Willows between 1967-68. The class was capable of speeds of up to 100mph, and was developed for hauling express passenger trains on the western region of British Rail, and were considered state-of-the-art motive power of the time. Originally numbered D400-D449, the class eventually received their TOPS numbers upon implementation throughout the system.
In the sixties, British Rail realised that the government was not going to fund electrification of the West Coast Main Line north of Crewe, and a diesel locomotive would have to be used on such services to Edinburgh and beyond. The national traction plan in 1965 recognised the need for fifty type four locomotives to operate these services.
In 1960, British Rail commissioned English Electric to built the agency a type 4 locomotive, as during this time, they were fulfilling the order of 22 Class 55 “Deltics”. However, later in 1961, English Electric introduced its 16 CSVT prime mover, which met the horsepower requirements on BR’s type 4 needs. Being fiscally conservative, English Electric decided to place the new prime mover into the shell of a Deltic, creating DP2, which began testing reliably around the midland region. The locomotive then moved to the Eastern Region where it outperformed the Deltics, this led BR to become increasingly interested in the 16 CSVT prime mover. BR sought to implement complex electronics into its new type 4, and consequently, DP2 was equipped with the new technology for testing in 1966.
The British Transport Commission recognised the success of English Electric’s DP2 prototype, which was reliable with very little service interruptions, and decided to commission English Electric to develop additional prototypes with the same prime mover as the DP2, however, including the British Transport Commission’s (BTC) new standards requiring locomotives to have flat cab fronts. The prototype emerged from English Electric’s facility not resembling the DP2, and included a flat nose and headcode boxes above the cab, along with the standard cast steel bogies, similar to those used on the Class 37. Adhering to the BTC’s new guidelines for locomotives to have flat cab ends, English Electric displayed several prototype front ends for the locomotive, however, the standard flat cab design was seen as most feasible, and was therefore chosen.
Upon entering service, the fifty “50s” began their life on the western region hauling passenger trains to Blackpool, Liverpool, Perth, and Windermere, in addition to their services along the west coast main line, and operating on branch lines as far north as Aberdeen. Oftentimes, the class could be seen double heading trains such as the Royal Scot, and the Anglo-Scottish services, due to their multiple working capabilities, of which only two came equipped from the factory, however, the entire fleet was eventually fitted.
The Class 50 was the final first generation diesel-electric locomotive ordered by British Rail during their transition away from steam, and upon delivery, the first to wear the new BR “rail blue” livery. Interestingly, British Rail leased the Class 50s from English Electric for their first ten years of service, which was due to British Rail’s strict budgetary constraints. English Electric agreed to lease the locomotives to the agency to secure the order. After this first decade, British Rail purchased them outright, shortly before overhauling the fleet.
The Class 50s had a relatively short stint on the northern WCML, as the line was electrified by 1974, and the class was displaced by the new Class 87 electric locomotive. Upon displacement, the locomotive found themselves working on the western region, operating services from London Paddington to points westward. The addition of the Class 50s on the western region resulted in the retirement of the region’s remaining diesel-hydraulic power, the Class 52 “Western” locomotives.
With the introduction of the high speed train (HST), the Class 50s were displaced from many services throughout the western region, and began working shorter services from London Paddington to Bristol Temple Meads, and eventually finding themselves on the Southwestern Mainline, operating trains out of London Waterloo to such destinations as, Salisbury, Exeter and Plymouth.
The Class 50 was technologically advanced at the time of production in the late sixties, as it included various speed regulating devices, however, these would later prove detrimental. Internally based on the DP2 prototype, which proved seemingly reliable, the Class 50 was powered by an English Electric 16 CSVT prime mover, producing 2,700 horsepower. The locomotives were dubbed “Hoovers” by enthusiasts because of the sound coming from the fans near the air intake. However, this intake design would cause problems for the class, as it was not designed to cope with the humidity present in Britain. This, in addition to the complexity of the speed control systems, led to various operational issues, and it was decided to refurbish the units after a little more than a decade in service.
Beginning in 1979, and continuing until 1984, the fleet was refurbished at Doncaster Works. The upgrades included eliminating features such as rhetostatic braking, and slow speed control, which was the cause of many operational concerns, due to their tendency to complicate the operation of the locomotive. Additionally, the intake fans were modified, as the previous arrangement trapped the air coming off the engine inside the locomotive, and prevented the intake of fresh air, which in turn caused moisture and dust to accumulate inside the locomotive, causing various failures, such as the main generator. However, the modification of the air intake system eliminated the infamous “hoover” sound emitting from the intake system. Additionally,per the BTCs mandate, a headlight was added to both ends of the locomotive, which was located in the center underneath the front cab windows.
Re-introduction Into Service
After refurbishment, the locomotives were stationed at Old Oak Common in London and Laira in Plymouth, as the fleet entered service once again on the West of England route, operating for the newly formed Network Southeast, as well as continuing to work express services out of London Paddington. In the late eighties, British Rail wanted to test the class on freight traffic, and chose 50049 to experiment the idea. The locomotive’s bogies were swapped for low-gear bogies for heavy freight traffic, and was painted in RailFreight grey livery. The unit began testing, hauling china clay around the area of Cornwall, however, due to wheel slip issues, the project was abandoned, and the locomotive returned to its assigned passenger duties after being repainted in BR blue.
The fleet worked the West of London services and Great Western Mainline (GWML) services until the early nineties, when the fleet began to display reliability issues. BR management decided that it was best to retire the units before they began to fail and cause delays. Many were taken from service and replaced with Class 47 locomotives, and eventually secondhand Class 165/166 and Class 159 DMUs were introduced into service. It was decided that the DMUs could best handle the constant stops required by the route to Exeter and would be more reliable, and have less chance of a major failure.
Before retirement, the Class 50s ran a few special excursions, one of which to the National Railway Museum, where 50033 was donated. In 1994, the railtours had ended, and the fleet was officially retired, with eighteen entering preservation.
Eighteen of these types are preserved, many of which are mainline certified, and can operate on the national rail network. These units were quite popular among enthusiasts and continue to attract trainspotters trackside.
Class 50 Names
The Class 50s were named after distinguished Royal Navy vessels, with prominent histories in both world wars.
|Wheel Diameter||3 ft 7 in|
|Wheelbase||56 ft 2 in|
|Length||68 ft 6 in|
|Width||8 ft 10 in|
|Height||12 ft 9 in|
|Axle Load||19 long tons|
|Weight||115 long tons|
|Fuel Capacity||1,540 imp gal|
|Prime Mover||English Electric 16 CSVT|
|Traction Motors||English Electric 538/5A|
|Tractive Effort||Max: 48,500lbf