NER Raven class C7 class 4-4-2 no. 727, depicted here at the south end of York station, was rebuilt by Gresley's design team from a C7 in 1931 to incorporate a booster apparatus and classified this engine as C9. The experiment ultimately proved to be unsuccessful and that arrangement was decommissioned in 1937. 727 was withdrawn in January 1943.
[Mike Morant collection]