Designed as front-line express passenger locomotives, the GWR ‘4073’ Class ‘Castles’ were built over a long period. The first of 155 new locomotives entered traffic in August 1923, while the last was finished at Swindon in August 1950 under British Railways. Sixteen further locomotives – 15 ‘Stars’ and one-off ‘Pacific’ No. 111 Great Bear – were also rebuilt as ‘Castles’, making 171 in total. No. 5081 was built in 1939 and originally named ‘Penrice Castle’ but was renamed ‘Lockheed Hudson’ in 1941. It was withdrawn from Cardiff East Dock in October 1963.