SR Merchant Navy class
The SR Merchant Navy class was a class of air-smoothed 4-6-2 Pacific steam locomotives designed by Oliver Bulleid. The first members of the class were constructed during the Second World War, and the last of the 30 locomotive in 1949. The class members were named after the Merchant Navy shipping lines involved in the Battle of the Atlantic, and latterly those which used Southampton Docks. They were known for reaching speeds of up to 105 mph.
About SR Merchant Navy class in brief
The SR Merchant Navy class was a class of air-smoothed 4-6-2 Pacific steam locomotives designed for the Southern Railway by Oliver Bulleid. The first members of the class were constructed during the Second World War, and the last of the 30 locomotive in 1949. The class members were named after the Merchant Navy shipping lines involved in the Battle of the Atlantic, and latterly those which used Southampton Docks. They were known for reaching speeds of up to 105 mph ; such speeds were recorded by examples including No. 35003 Royal Mail and Nos. 35005 Canadian Pacific and 35028 Clan Line. The Merchant Navyclass operated until the end of Southern steam in July 1967. A third of theclass has survived and can be seen on heritage railways throughout Great Britain. The design incorporated a number of novel features, compared to then-current steam locomotive practice in Britain. It was intended to use a gear-driven valve gear, but space restrictions within the frames and wartime material shortages led Bulleids to use his novel chain-driven gear. It later gained a bad reputation, because it could cause a highly irregular valve events, compounded by the fast-moving locomotive. The entire system was located in a sealed oil bath, providing constant lubrication to the moving parts of the locomotive, which was another unique design among British locomotive design. The locomotIVES were equipped with the unusual Firth Brown Firth wheels, which were stronger than 6ft 2 in in and lighter than 2 in 2 in Firth Firth 2 in Brown Brown 2 in 1, which both driving wheels and both lighter than 1in 1/2.
The Southern Railway was the most financially successful of the \”Big Four\”, but this was largely based on investment in suburban and main line electrification. The new design was intended for express passenger and semi-fast work in Southern England, though it had to be equally adept at freight workings due to the nominal’mixed traffic’ classification. The Southern Railway was one of the first to use welding in the construction process, which enabled easier fabrication of components during the austerity of the war and post-war economies. Most of the detailed design was undertaken by the drawing office at Brighton works, but some work was also undertaken by Ashford and Eastleigh. The final design was based on Nigel Gresley’s P2 locomotive and was planned to have a Hemholtz pony truck; BulleID himself had worked with Gresleys in the past. The last of these locomotiving was built in 1949 and is now on display at the National Railway Museum in London. It is one of only a handful of locomotive classes to have survived into the 21st century, and is the only one to have been built during the First World War and the Second. World War II was a major factor in the decision to build the class, as the railway had lagged behind the others in terms of modernising its ageing fleet of steam engines.