The doyen of one of the most successful express locomotive classes

November is a quiet month for the steam enthusiast, with most preserved lines being closed for maintenance. So other than having fun with model railways (and of course, taking part in Movember), it is also a good time to visit museums. Swindon’s STEAM – Museum of the Great Western Railway is one such place very worthy of a visit. It tells the story of the former Swindon works – this includes some very important exhibits from the National Collection. Tonight we look at one of these – 4073 Caerphilly Castle.This locomotive was the first of 171 Castle class locomotive’s built by the Great Western Railway. The Castle class is regarded as one of the most successful locomotive classes ever produced in the UK. When built in 1923, 4073 Caerphilly Castle was the most powerful express locomotive in the country – technically, even more powerful than 4472 Flying Scotsman!

A development from Churchward’s Star class, Collett’s Castle class shared it’s predecessor’s four cylinders and and Belpaire firebox but had a lighter more powerful boiler. Rather delightfully, at STEAM you can go under the locomotive to see the inside motion of the internal cylinders for yourself!

It made it’s public debut in 1923 on 23rd August at Paddington station. Following this in 1924, 4073 was displayed at the British Empire Exhibition at Wembly before going to Old Oak Common engine shed to continue it’s revenue earning career, that would last until 1960.

The Castle class were made particularly famous by their speed demonstrated by hauling the Cheltenham Spa Express, also known as the Cheltenham Flyer, the “World’s Fastest Train”. This nickname was very apt considering the performance of classmate 5006 “Tregenna Castle” in 1932, that managed an average speed of 81.6 miles per hour – an amazing feat for a steam hauled express of the time. At STEAM you can find out more about the express, with 4073 having the “Cheltenham Flyer” headboard on it’s smokebox.

You can also find out a lot more about 4073 at STEAM, one particularly interesting fact being the £5,565 cost to build, equivalent to over £100,000 today!

I hope you enjoy looking through the photograph’s of this beautiful machine!