Steam Locomotives of the Great Western Railway after 1923
When the British railway companies were grouped in 1923, the Great Western Railway (GWR) was the only one of the four major companies to retain its original name and identity. It absorbed several railways in Wales and western England, including the Cambrian Railways, the Taff Vale Railway, the Rhymney Railway and the Barry Railway. This considerably expanded its network and brought a large number of locomotives of different designs into its fleet. While many of these continued in service for several decades, the GWR gradually replaced them with its own standard designs. The company's locomotive works at Swindon remained the centre of development and production.
In 1922, Charles Benjamin Collett had succeeded George Jackson Churchward as Chief Mechanical Engineer. Instead of introducing fundamentally new concepts, he continued the standardisation programme of his predecessor and developed improved versions of existing designs. The use of interchangeable components, standard boilers and common design principles helped to simplify maintenance and reduce operating costs. This resulted in a remarkably uniform locomotive fleet, despite the great variety of duties on the expanded network.
Collett's first major express locomotive design was the Castle class of 1923, a four-cylinder 4-6-0 developed from Churchward's Star class. With a larger boiler and improved cylinders, it combined high power with relatively low weight and became one of the most successful British express locomotive classes. In 1927, the even more powerful King class followed for the heaviest express trains on routes with sufficiently high permitted axle loads. These four-cylinder 4-6-0 locomotives represented the peak of GWR express locomotive development and were among the most powerful passenger locomotives in Britain.
For mixed traffic, Collett introduced the Hall class in 1928, which combined elements of the Saint class with smaller driving wheels and became one of the most versatile locomotive types of the GWR. It was followed by the Grange class in 1936 and the lighter Manor class in 1938, both of which used many standard components. While the Granges were intended for general mixed-traffic duties, the Manors were particularly suited to routes with lower permitted axle loads. The existing 2-8-0 freight locomotives of Churchward's 2800 class were also further developed, resulting in the 2884 class with more modern cabs and other improvements.
A large number of new tank locomotives were also introduced during this period. The 5600 class 0-6-2T was developed for the heavy coal traffic in the Welsh valleys, while the 5700 class 0-6-0 pannier tanks became one of the most numerous British tank locomotive classes. They were used for shunting, local freight and passenger services throughout the GWR network. Other important types included the 4575 and 6100 classes of 2-6-2T locomotives, the 1400 class 0-4-2T for branch lines and auto trains, and the massive 7200 class 2-8-2T locomotives, which were rebuilt from earlier 2-8-0T types to increase their coal and water capacity.
In 1941, Frederick William Hawksworth succeeded Collett as Chief Mechanical Engineer. During the Second World War, locomotive development was restricted by shortages of materials and the demands of wartime traffic. Hawksworth therefore concentrated mainly on improving existing designs, although he also introduced several new classes. These included the 6959 Modified Hall class of 1944, the 9400 class of heavy 0-6-0 pannier tanks and the 1000 County class of 1945. The latter were powerful two-cylinder 4-6-0 locomotives with a relatively high boiler pressure and were intended for express passenger and mixed-traffic duties. Hawksworth also introduced the 1500 class of outside-cylinder pannier tanks, although these were not built until after nationalisation.
On 1 January 1948, the GWR became the Western Region of the newly formed British Railways. Many of its standard locomotive classes continued to be built after nationalisation, and the characteristic Swindon design principles remained influential. The Castles and Kings continued hauling important express trains, while the Halls, Granges, Manors and numerous tank locomotives remained indispensable for everyday operations. Although diesel traction gradually replaced steam from the 1950s onwards, GWR locomotives continued in regular service until the final years of steam on the Western Region in 1965. A considerable number have survived in preservation, making the GWR one of the best-represented British railway companies on today's heritage railways.
