The Duchess of Sutherland #6233 is one of the Princess Coronation Class Pacific Type (4-6-2) locomotives built for the London, Midland and Scottish Railway (LMS). Designed by locomotive engineer Sir William Arthur Stanier, it was built in 1938 at the fabled Crewe Works. The class was the most powerful steam locomotives ever used in Britain; producing 2,511 drawbar horsepower during testing.
The locomotive was originally built with a single chimney but was fitted with a double blast-pipe chimney in 1941 after testing with a sister locomotive showed an increase in power with the new chimney. It was fitted with its characteristic smoke deflectors in 1945 to help manage smoke drift. At the time of her retirement, the locomotive had amassed 1,650,000 miles in service.
The locomotive is preserved today in running condition. It has worn several paint schemes including BR Brunswick Green and LMS Black throughout its lifetime. In September of 2018, the engine was painted in its original LMS "Crimson Lake" livery to mark its 80th birthday.