Four cylinder 4-6-0 passenger train steamlocomotive # 4073 "Caerphilly Castle" of the Great Western Railway, exhibited at the STEAM Museum of the GWR at Swindon. This was the first built of the famous 171 "Castle" class locomotives, designed by Charles Collett, and was built in 1923 at the Swindon Works. The Castle class was noted for superb performance overall, and notably on the Cheltenham Flyer during the 1930s: for example, on 6 June 1932 the train, pulled by 5006 Tregenna Castle, covered the 77.25 miles from Swindon to Paddington at an average speed of 81.68 mph start-to-stop (124.3 km at an average speed of 131.4 km/h). This world record for steam traction was widely regarded as an astonishing feat. # 4073 was withdrawn in 1960 and is owned by the National Railway Museum.