4079 Pendennis Castle, GWR Castle Class

A preserved GWR Castle Class 4-6-0, built at Swindon Works in 1924. Withdrawn from British Railways service in 1964. Exported to Australia in 1977 and preserved there, before being repatriated to Britain in 1994.

4079 Pendennis Castle holds a unique place in British locomotive history: in the 1925 locomotive exchange trials between the GWR and LNER, she was sent to work on the Great Northern main line and demonstrably outperformed Sir Nigel Gresley's A1 Pacifics — using less coal and water while maintaining equivalent or better timings. The revelation that long-travel valves rather than compound expansion were the key to thermodynamic efficiency forced Gresley to redesign his valve gear, transforming LNER locomotive performance and producing the A3 class. Without Pendennis Castle's 1925 performances, Mallard's 1938 world speed record might never have been set. Preserved in Australia from 1977, she returned to Britain in 1994 and is now based at Didcot Railway Centre, operated by the Great Western Society.

Last recorded as based at Didcot Railway Centre, owned by the Great Western Society. Operating status: Heritage railway service / cycles. Current livery: GWR Brunswick green.

Location, livery and operating status last confirmed pre-2024 and subject to change. Check with the Great Western Society for current information.