In May 1945 work began at Brighton on the construction of a class of locomotive that was to become very familiar to the region for the last twenty years of steam railways. Oliver Bulleid was the last chief mechanical engineer of the Southern Railway and four years earlier he had introduced a revolutionary, large, streamlined locomotive – the Merchant Navy class – for mainline use. However it was decided that a lighter version would be required for use on more weight-restricted routes and so 110 engines of the West Country and Battle of Britain classes were constructed over the next six years. By January 1951 engines, blessed with names such as Plymouth, Dartmoor, and Tamar Valley were familiar sights along the line that formerly ran close to West Country Close at Weston Mill.
To improve their performance, economy and servicing, sixty of the locomotives were rebuilt, starting in 1957, but due to the dieselisation of the region all had disappeared by the mid-sixties. Happily however some twenty of these fine locomotives have survived into preservation.