Vincent Raven designed the Atlantics of the class V2 in 1911 with a single expansion three-cylinder engine. He had ten saturated and ten superheated locomotives built, which had cylinders of different dimensions and were soon renamed the Z and Z1 classes. From 1914, thirty more were built in the superheated version, the first ten were rebuilt to the same variant and all renamed Class Z. Some locomotives were used to test feedwater heaters, boosters and uniflow cylinders. At the LNER they became class C7. The last survivors came to British Railways in 1948, but were immediately retired. 