The London, Midland and Scottish Railway (LMS) Princess Royal Class is a class of express passenger 4-6-2 steam locomotive designed by William Stanier.
The Princesses are related to the GWR King Class, the general outline essentially being a King with a larger firebox supported by additional trailing wheels. This origin is explained by the designer William Stanier coming from the GWR to the LMS. When originally built, they were used to haul the famous Royal Scot train between London Euston and Glasgow Central.
The class was withdrawn in the early 1960s in line with British Railways' modernisation plan. Twelve examples were built at Crewe Works, between 1933 and 1935, for use on the West Coast Main Line. Two are preserved.
