LMS Crab Class

George Hughes became the LMS's first Chief Mechanical Engineer at the 1923 Grouping, bringing his Lancashire & Yorkshire Railway design office to the new combined company's headquarters. The early LMS was hampered by rivalry between the Crewe (LNWR-derived) and Derby (Midland-derived) engineering offices, both of which wanted to maintain their own design traditions. Hughes's decision was to base the new mixed-traffic 2-6-0 on L&YR design principles, large outside cylinders, parallel boiler, Belpaire firebox, and to have it built at both Crewe and Horwich.

The result, completed in October 1926, was a startlingly distinctive engine. The cylinders were mounted high to allow access for maintenance, requiring a noticeably raised running plate that exposed the upper portion of the driving wheels. The combination of high-pitched cab, large outside cylinders, and the curved running plate over the cylinders gave the class a profile reminiscent of a crab, and the nickname stuck almost immediately, despite the LMS publicity department's initial reluctance to embrace it.

The first 70 engines (Nos 13000–13069) were built at Crewe between October 1926 and December 1928. The remaining 175 engines were built at Horwich Works between 1929 and November 1932. By the time of the last delivery, Henry Fowler had succeeded Hughes as LMS CME (in 1925, but Hughes-designed locomotives continued to be built into the early 1930s). The Crab thus carries both designers' names, formally the "Hughes-Fowler 2-6-0", although the design is fundamentally Hughes-derived L&YR practice.

From 1930 a small number of Crabs were modified for testing, including experiments with Caprotti rotary-cam valve gear (the first major British application). The Caprotti Crabs (Nos 13243 and 13244) were not a long-term success and most experiments were reversed.

The Crab was the LMS's standard mixed-traffic and fast-goods engine through the late 1920s and 1930s. The class worked across the entire LMS system on every grade of duty, secondary main-line passenger, the Settle & Carlisle expresses, fast freight from Carlisle to Glasgow on the Glasgow & South Western route, parcels and milk traffic into London Euston and St Pancras, and seasonal holiday extras. Their general usefulness made them universally popular with crews despite the unconventional outline.

British Railways inherited 245 Crabs in 1948 (one had been withdrawn pre-nationalisation) and continued the class on similar duties through the 1950s. The introduction of the BR Standard Class 4MT 2-6-0 from 1953 onwards began to displace the Crab from front-line work, but the class remained on cross-country and freight services into the 1960s.

Withdrawal began in earnest from 1961 as the Modernisation Plan diesels arrived in numbers. The bulk of the class was withdrawn between 1962 and 1965; the last Crabs in BR service were withdrawn in early 1967, by which point the great majority had been replaced.

The class's instantly recognisable "crab" appearance comes from a deliberately raised running plate, which exposed the upper portion of the driving wheels and gave the engine a distinctly different outline from contemporary LMS designs. The large outside cylinders mounted at a steep angle, the high-pitched cab, and the curved running plate over the cylinders combined to give the class a profile reminiscent of a crab, the LMS publicity department initially disliked the nickname but it stuck. The class wore standard LMS unlined black livery throughout most of its life; BR mixed-traffic black after 1948. Two outside cylinders gave the class a distinctive two-beat exhaust pattern (rather than the four-beat of three- or four-cylinder engines). The class was never named.

13000 (originally LMS; later 2700, then 42700), first of class, completed at Crewe in October 1926. Preserved at the National Railway Museum, York as part of the National Collection. Withdrawn from BR service in 1961 with a recorded mileage of approximately 1,200,000, typical for a Crab. The engine has been a static exhibit at York for many years.

13065 (originally LMS; later 2765, then 42765), preserved at the East Lancashire Railway. Built at Horwich in 1927. Withdrawn from BR in 1966 and rescued for preservation. Restored to working order at Bury and main-line registered for charter and special-event work.

13244 (originally LMS; later 2944, then 42944), last of class, completed at Horwich in November 1932. Withdrawn 1965; not preserved.

LMS era (1926–1947): the class was distributed across the entire LMS system. Major Crab allocations were at Crewe (Crewe North and Crewe South), Saltley (Birmingham), Holbeck (Leeds), Polmadie (Glasgow), Carlisle Kingmoor, Wakefield, and the major Lancashire and Yorkshire sheds (Newton Heath, Bury, Wakefield) reflecting the L&YR's influence on the class's design.

British Railways London Midland Region (1948–1967): the class continued widely distributed across the BR LM Region. By the early 1960s major Crab allocations were at Saltley (Birmingham), Bristol Barrow Road, Carlisle Kingmoor, Wakefield and the Midland Main Line sheds. The class lasted in BR service into 1967, withdrawal accelerating in the early 1960s as Modernisation Plan diesels arrived in numbers.

LMS (1926–1947): standard LMS unlined black for goods and mixed-traffic engines, with the LMS coat of arms or the simple "LMS" lettering on the tender. Some early examples briefly carried red oxide undercoat for a short period before final painting.

British Railways early (1948–1956): mixed-traffic black with red, cream and grey lining; early lion-and-wheel emblem on the tender.

British Railways late (1956–1967): BR mixed-traffic black with the late BR crest, often unlined as the cleaning standards declined towards the end of steam.

Preservation: 42765 has been turned out at the East Lancashire Railway in BR mixed-traffic black with the early lion-and-wheel emblem, a representative Crab livery for the BR period.