62005 at Barrow Hill in April 2009. ©Hugh Llewelyn
The K1 was initially designed by Edward Thompson, when he took a Gresley K4 and had it rebuilt to a two-cylinder mogul by his assistant, Arthur Peppercorn. Peppercorn utilised the rebuilt K4 as a basis for constructing a new class of 2-cylinder 2-6-0 locomotives which became the Class K1. 70 of the new mixed-traffic K1s were ordered for LNER and were built at the North British Locomotive Company in Glasgow. They were the last locos built to an LNER design and only came into service post-nationalisation under British Railways. The locomotives were used extensively across the North East of England and on the West Highland Line in Scotland. Their lifespan was brief, being built between 1949 - 1950 and retired between 1962 and 1967. One example just managed to escape scrapping and can still be seen to this day at the North Yorkshire Moors Railway or on outings along the line from Fort William to Mallaig.
(Information provided by Wikipedia)