SECR K and SR K1 classes

The SECR K class was a type of 2-6-4 tank locomotive that Richard Maunsell designed in 1914 for express passenger duties on the South Eastern and Chatham Railway, which ran between London and south-east England. The Southern Railway K1 class was a three-cylinder variant designed in 1925 to suit a narrower loading gauge. Twenty-one engines were built, twenty K class and one K1, the first in 1917 and the rest in 1925 and 1926, and they were named after rivers and known as the River class. Crews called them Rolling Rivers because they were unstable at speed, and after the 1927 Sevenoaks accident they were rebuilt as 2-6-0 U and U1 class engines, the last being withdrawn in 1966. Nine sets of parts for the K class were conveyed to Armstrong Whitworth for assembly.