SR West Country and Battle of Britain classes

The SR West Country and Battle of Britain classes were air-smoothed 4-6-2 Pacific steam locomotives designed for the Southern Railway. They were amongst the first British designs to use welding in the construction process, and to use steel fireboxes. A total of 110 locomotives were constructed between 1945 and 1950, named after West Country resorts or Royal Air Force. The classes operated until July 1967, when the last steam locomotive on the Southern Region were withdrawn.

About SR West Country and Battle of Britain classes in brief

The SR West Country and Battle of Britain classes, collectively known as Light Pacifics or informally as Spam Cans, are air-smoothed 4-6-2 Pacific steam locomotives designed for the Southern Railway. They were amongst the first British designs to use welding in the construction process, and to use steel fireboxes. A total of 110 locomotives were constructed between 1945 and 1950, named after West Country resorts or Royal Air Force. Due to problems with some of the new features, such as the Bulleid chain-driven valve gear, sixty locomotics were rebuilt by British Railways during the late 1950s. The classes operated until July 1967, when the last steam locomotive on the Southern Region were withdrawn. Although most were scrapped, twenty locomotive are preserved on heritage railways in Britain. The design was based on experience gained from the Merchant Navy class, which gained notoriety when things went wrong with the tandem-moving valve gear. It is not clear why the design was subsequently enlarged to become a smaller version of the Merchant navy class 4- 6-2 as the likely traffic requirement did not warrant such lavish provision. The incorporation of components from that class enabled standardisation during wartime production difficulties. In order to improve the 21-ton axle loading, the design to operate on routes where the Maunsell 2-0s were the largest allowed, the cab was remodelled to comply with reduced loading gauge over some routes. It became the new design and became the now-infamous locomotive design in British locomotive history.

It gained notoriety because it was difficult to access and reverses in tandem with the fast-moving steam reverses, which were difficult to use in the early days of steam. The locomotive was designed by Chief Mechanical Engineer Oliver Bulleid, who had previously worked on the West Highland Line and the London and North Eastern Railway. The West Country branches were worked by the ageing T9-class 4-4-0 and the versatile N-class 2-6 0, which could be better utilised on mixed-traffic services elsewhere. The Southern Railway’s less heavily used lines in the West Country beyond Salisbury did not merit the cost. As a result, an order was placed with Brighton railway works in April 1941 for twenty passenger locomotive of a type to be determined. Although the design would have been inadequate for the Kent Coast lines, which required a powerful 2-5-0 or 4-5 0 class, it could be used on other routes in the south-west of England and the Kent coast. The earliest drawings were for a moderately sized 2-8-0 with similarities to the LNER’s K4-class, which Bulleids had helped design for the West Highlands Line. However, such a design would not have been suitable for the South East. The final design was for a lighter, more powerful 4-7-0 class. It was designed to permit use on both electrified and non-electrified routes without impeding the intensive use of the system by passenger trains.

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