The Castle class locomotives were a group of 4-6-0 steam locomotive of the Great Western Railway. They were originally designed by the railway's Chief Mechanical Engineer, C B Collett , for working the company's express passenger trains.

History

A development of the earlier Star Class, one hundred and sixty-five (165) were built, over a 25 year span from August 1923 to August 1950. They were numbered 4073–4099; 5000–5099; 7000–7037.

Although most were built new, sixteen locos were rebuilt from older locomotives—fifteen Star Class locomotives; and the Great Western Railway's sole 4-6-2 locomotive, number 111 The Great Bear.

The Castle class was noted for superb performance on The Cheltenham Flyer during the 1930s: on June 6th 1932, pulled by 5006 Treganna Castle , the train covered 77 miles (124 km) from Swindon to Paddington at an average speed of 81.68 miles per hour (131.45 km/h). This world record for steam traction was widely regarded as an astonishing feat.

In 1926, number 5000 Launceston Castle was loaned to the London, Midland and Scottish Railway where it ran trials between London to Carlisle. It was rumoured that LMS tried to persuade GWR to build a batch of Castles for use on the West Coast Main Line.

Withdrawal started in the 1950s; the last to be withdrawn was Clun Castle.

A few survive in preservation as either working examples or static exhibits, including 4073 Caerphilly Castle , 4079 Pendennis Castle, 5029 Nunney Castle , 5080 Defiant and 7029 Clun Castle .

Specifications

Cylinders: 4; 16″ (406 mm) diameter, 26″ (660 mm) stroke
Valve gear: inside cylinders – Walschaert 's; outside cylinders – derived from inside cylinders via rocking bars.
Valves: Piston Valves
Boiler Presure: 225 lbf/in² (1.55 MPa)
Driving wheel diameter: 6′ 8.5″ (2.04 m)
Tractive Effort: 31,625 lbf (140.675 kN)
Engine Weight: 79 tons 17 cwt (81.1 Mg)
Tender Weight: 46 tons 14 cwt (47.44 Mg)

List of Locomotives

References

Collett & Hawksworth Locomotives—A Pictorial History, Brian Haresnape, Ian Allen Ltd, 1978, ISBN 0-7110-0869-8