The all passed to the London and North Eastern Railway at the 1923 grouping and received the classification J20.

These locomotives were fitted with 20-by-28-inch (508 mm × 711 mm) cylinders and 4-foot-11-inch (1.499 m) wheels, while the Belpaire firebox-fitted boiler was identical to that fitted to the Class S69 4-6-0s.

They were the most powerful 0-6-0 tender locomotive in Britain until the arrival of Oliver Bulleid's Q1 class for the Southern Railway in 1942.

Between 1943 and 1956 the class was rebuilt with round-top fireboxes, and reclassified as J20/1.

[1][2] At nationalisation in 1948, British Railways added 60000 to their LNER numbers.