British Rail’s transition to diesel wasn’t immediate. In the 1950s, the company launched a "Pilot Scheme" to test different locomotives before committing to a full fleet. As part of this initiative, small batches of diesel locomotives were ordered from various suppliers. Among them were the UK Type 2 locomotives - versatile workhorses that would help shape the future of British rail.
Designed to replace steam engines, Type 2 locomotives produced between 1,001 and 1,499 horsepower, balancing power and efficiency. They became a familiar sight on British railways, handling both passenger and freight duties.
Read on to discover the history of each Type 2 locomotive that travelled the UK’s tracks and learn which one has unexpectedly resurfaced decades later.
The 11 Type 2 UK Locomotives
A total of 11 UK type 2 locomotives were introduced. Some have enjoyed more success than others, and only one remains with us today in a revived form.
Class 21 (NBL) (1958-1968)
Built by the North British Locomotive Company (NBL), Class 21 was intended for commuter services in the Eastern Region. However, its reliability issues led to an early transfer to Scotland, where its performance remained inconsistent. Problems with diesel leaks, overheating and overall mechanical instability were common. Even with modifications increasing their power to 1,100 horsepower, the locomotives continued to underperform.
British Rail withdrew the Class 21 locomotive from service in 1967. By August of the following year, they had scrapped the initial 38. No Class 21s remain today, however the final 20 units were rebuilt with Paxman Ventura engines and reclassified as Class 29s.
Class 22 "Baby Warship" (1959-1972)
Class 22s earned the "Baby Warship" nickname for their smaller size and resemblance to the “Warship” British Rail Class 41 trains. They mainly worked in the West of England, before expanding to Bristol and London Paddington.
The Class 22s had a rocky start with multiple transmission and engine problems. This led to trains with more powerful engines started to relegate the Baby Warship to less important routes.
The downfall of the Class 22 was compounded by the closure of the North British Locomotive Works (NBL), which manufactured them, making spare parts difficult to source. The fleet gradually retired, by 1972 the Class 25 locomotives superseded them.
Class 23 "Baby Deltics" (1959-1971)
Another locomotive earning a baby a ‘Baby’ moniker, the Class 23 resembled the iconic Class 55 Deltic. Primarily used for express passenger services between London, the Midlands, and the South West, it was a versatile and reliable locomotive, also frequently employed for freight and parcel traffic.
Class 23s were mechanically unique, as they were the only trains of their time to be powered by a 9-cylinder Napier Deltic T9-29 engine. Despite initially showing promise, they soon encountered significant mechanical challenges. Frequent gearbox failures and drive shaft issues plagued their reliability, while persistent overheating often led to complete engine breakdowns, ultimately sealing their fate.
British Rail began withdrawing the trains from service in 1968, by 1971 all Class 23s were retired. However, the Baby Deltic Project is working to recreate one using an original engine.
Class 24 (1958-1980)
Like many of its contemporaries, the Class 24 locomotive featured a boxy, functional design. However, what set it apart was the inclusion of a steam-heating boiler, ensuring passenger comfort in colder months.
Not all Class 24s were equipped with this feature, though. Ten units were built without boilers, instead fitted with air compressors to support their primary role - hauling heavy iron ore to Consett in the North East of England.
Renowned for their reliability, Class 24s remained in service for over two decades, outlasting many of their predecessors and proving to be one of the most enduring locomotives of their time. The Class 24s began to be withdrawn from service in the 1970s, with the last unit retiring in Crewe in 1980.
Class 25 (1961-1987)
An evolution of Class 24, Class 25 locomotives were upgraded with improved generators and traction motors. While primarily used for freight, many were fitted with boilers for passenger duties. In the 1970s, they were a staple of the British Rail network but a less common sight in the Southern and Eastern Regions.
The phasing out of the Class 25s began in the 1980s, with the final unit retiring from service in 1987. However, railway societies kept the locomotives in operation for enthusiast trips until March 1991, providing railfans with one last opportunity to see them in action. Today, 20 Class 25s are preserved and still in existence.
Class 26 (1958-1994)
The Class 26 locomotives, also known as the BRCW Type 2, were built with robust steel bodies and fibreglass cab roofs. They became a familiar site in Scotland, serving both passenger and freight routes. For a period, British Rail also deployed them on commuter routes to London King's Cross.
Class 26s were also used on the prestigious "Royal Highlander" service between Inverness and London Euston. This demanding route required multiple locomotives to tackle the journey to Perth. On some occasions, Class 26s were paid with Class 24s to provide the necessary power to pull sleeping cars over the more difficult sections.
In addition to their passenger duties, Class 26s were excellent for freight work. The first seven locomotives moved coal to Cockenzie Power Station and Ravenscraig Steel Works. Many Class 26s were refurbished in the 1980s, however, the closure of Ravenscraig led to a significant decline in demand.
The last of the Class 26s was retired in 1994, though several heritage railways now maintain these locomotives in preservation.
Class 27 (1961-1987)
The Class 27s were a more powerful version of the Class 26s. Initially based at London Cricklewood, Thornaby, and Glasgow Eastfield, they operated on both passenger and freight routes from these locations. Later, like many of the 26s, a significant number of Class 27s were moved to Scotland to serve on the West Highland Line.
British Rail used Class 27s on push-pull operations on the Edinburgh Waverley to Glasgow Queen Street express service.
The withdrawal of the Class 27s began in the late 1970s, and by July 1987, most of the fleet had been retired. Today, eight of these locomotives are preserved by rail heritage organisations.
Class 28 (1958-1968)
Class 28 locomotives, along with the Class 23 Baby Deltic, were part of the Pilot Scheme that tested both two-stroke and four-stroke diesel engines. While most diesel engines were four-stroke, British Rail wanted to compare both types side by side for performance.
The Class 28s were powerful machines capable of pulling heavy loads without slipping, thanks to their unique five-axle design. All 20 units were assigned to the Midland Division of the London Midland Region, where they operated in pairs on the London-Glasgow "Condor" express freight service. They performed other tasks, like hauling the London-Glasgow sleeper from Carlisle. After an upgrade in 1961, they were all moved to Barrow-in-Furness.
Due to foreign exchange issues, the Class 28s were fitted with Crossley motors instead of the preferred GM motors. While the trains were reliable in terms of electric and mechanical performance, the Crossley engines proved troublesome. Although British Rail considered replacing them, they chose not to straight away, and they eventually phased out between 1967 and 1968.
Today, only one Class 28 remains preserved: the D5705, which can be found on the East Lancashire Railway. If you look closely enough, you'll notice this locomotive was an inspiration for The Railway Series books and Thomas and Friends.
Class 29 (1958-1971)
The Class 29 locomotives began life as something entirely different. They were a rebuild of 20 unreliable North British Type 2 with engineers from Paxman and British Rail replacing the original MAN engines with Paxman's Ventura V12 engines between 1963 and 1967.
Once upgraded, the Class 29s were used for both passenger and freight services with the new engines proving to be much more powerful and reliable. However, despite improvements, the first Class 29 was retired in May 1969, with the rest following suit by 1971. All 20 units were eventually scrapped in 1972, and none have been preserved.
The reason for their phase-out was British Rail’s shift towards using standard parts across its fleet. The Class 29s were relatively few in number and relied on non-standard components, which made them more difficult and expensive to maintain.
Class 31 (1957-2017)
The Class 31s were the longest-lasting Type 2 locomotives with six decades of service. British Rail maintained them well, upgrading their engines over time to enhance reliability and ensure their long-term service.
Class 31’s design proved so successful that it led to the creation of several subclasses, each with different heating systems to ensure passenger comfort. The locomotives were a key part of the rail network, initially intended for the Eastern Region, but eventually spreading to the Western and London Midland regions as well.
The Class 31s gained a strong following among railway enthusiasts, with 36 preserved models, including both the first and last locomotives built.
Travelling with UK Type 2 locomotives today
While many Type 2 locomotives have faded into history, their influence on British railways endures.
A new version of a Class 21 train unexpectedly returned 22 years later, with Euro Cargo Rail and Eurotunnel using 16 Class 21 (MaK) trains for freight and emergency rescue.
From heritage railways to modern freight services, the evolution of these locomotives highlights the balance between innovation and reliability. Whether exploring railway history or experiencing a preserved locomotive in action, Type 2s remain an integral part of the UK’s rail legacy.