The Caledonian Railway 812 and 652 Classes were 0-6-0 steam tender locomotives designed by John F. McIntosh for the Caledonian Railway and introduced in 1899. They had the same boiler type as the 721 “Dunalastair” Class 4-4-0s. Seventeen were fitted with the Westinghouse air brakes for passenger train working, including the only surviving engine of the class, No. 828. All 96 passed to the London, Midland and Scottish Railway at the 1923 grouping. Only three, 17567, 17598 and 17610, had been withdrawn by the time of nationalisation in 1948. The last locomotive in service was not withdrawn until 1963. Locomotive 828 (LMS 17566, BR 57566) is the sole survivor of the class and is an important example of Scottish industrial heritage. It is currently in service at the Strathspey Railway. In The Railway Series children's books by the Rev. W. Awdry, the characters Donald and Douglas ("the Scottish twins"), are based on the Caledonian 812 class.