The GCR built 21 locomotives at Gorton Works in three batches between 1911 and 1917.[1] They ordered a fourth batch of ten from Gorton, but this was not built until after the 1923 Grouping, under which GCR became part of the newly formed London and North Eastern Railway (LNER).[1] The LNER then ordered a fifth batch of 13 to a modified design, incorporating reduced boiler mountings and detail differences, and these were built by the outside contractors Hawthorn, Leslie & Co. during 1925–26 (works numbers 3616–28).[2]
No. 5447 was withdrawn in 1942 because its frames were badly cracked.[3] In 1943, the remaining engines were allocated new numbers in the 9800–42 block, but these were not applied until 1946.[4] Forty-three locomotives passed to British Railways in 1948, and between 1948 and 1951 their numbers were increased by 60000.[5] The class was divided into two parts in December 1948 as follows:[2]
A5/1, 69800-69829: Built at Gorton to Robinson's design
A5/2, 69830-69842: Built by Hawthorn, Leslie with modifications by Gresley