GWR/BR (WR) Castle Class Manual: A guide to the history and operation of one of Britain's most successful express passenger steam locomotive types

The Great Western Railway 4073 Class, or Castle Class locomotives were the pride of the GWR when introduced in the mid-1920s, and were heralded as Britain's most-powerful express passenger locomotives. 171 Castles were built or converted between 1923 and 1950, and eight preserved examples survive today.