The 'Castle' Class

When Charles Benjamin Collett succeeded Churchward in 1922 as Chief Mechanical Engineer of the Great Western Railway, almost immediately he was faced by the need to design and build a new class of locomotives that was more powerful than the existing classes of GWR 4-6-0 express passenger locomotives.The result was the Castle Class, the first of which - No. 4073 Caerphilly Castle - was outshopped from Swindon Works in July 1923 barely 18 months after Collett's appointment. This locomotive appeared at the Wembley Exhibition at Wembley in 1924 as an exhibit for the Great Western and was displayed next to the LNER A1 Class Flying Scotsman.

Over the next 27 years a total of 179 locomotives were built. Of these the majority were new engines with a small number being rebuilt from the older mainly Stars class. As befitted the fact that Collett had been Churchward's principal assistant, the new class represented a further development of the standard designs pioneered by Churchward, but achieving an increase in power of some 10% over the Star class. This was achieved by increasing the diameter of the cylinders and modifying the boiler.

After the Second World War, and indeed after nationalisation in 1948, Castles continued to be turned out by Swindon works. The later engines were of a slightly modified design by F W Hawksworth with the larger straight-sided all-welded tender, with some Castles being fitted with larger superheaters, double blastpipes and chimneys. The last of the Castles, was number 7037 and named Swindon by HRH Princess Elizabeth (as she then was) on a visit to Swindon works in 1950.

As a class these superb engines earned a fine reputation for their performance, with exceptional economy in coal consumption and haulage capacity plus an ability for substained high speed running, particularly on services such as the Cheltenham Flyer, regularly achieving speeds over 90 mph. They came to dominate the Great Western Railway's express passenger services for almost 40 years and were to remain dominant on most duties, even after the arrival of the later King class, until the final demise of Western Region steam in the early 1960s.

Charles Benjamin Collett

Chief Mechanical Engineer (1922-1941) - Click here