LNER Thompson/Peppercorn Class K1

The London and North Eastern Railway Class K1 is a type of 2-6-0 Mogul steam locomotive designed by Edward Thompson, who preferred a simple two-cylinder design to his predecessor's three-cylinder one. A prototype was made in 1945 by rebuilding K4 number 3445 MacCailin Mor at Darlington Works, and Arthur Peppercorn, who replaced Thompson as chief mechanical engineer, made that rebuild the basis of the new class with a redesigned running plate and larger tenders. An order for 70 was placed with the North British Locomotive Company of Glasgow, and they were the last steam locomotives built to an LNER design, although all were delivered under British Railways ownership. They entered service between May 1949 and March 1950, were all withdrawn between 1962 and 1967, and one is preserved.