Album containing sketch of the first Standard Class Pacific locomotive drawn by Ernest Stewart Cox (E.S. Cox)

Photograph album containing official BR photographs with Sketch of the first Standard Class Pacific locomotive enclosed drawn by Ernest Stewart Cox (E.S. Cox) on squared paper. The sketch was photographed at its time of creation for publicity purposes. It is shown being inspected by Robert Riddles and his assistants E.S. Cox and Roland Bond. Accrual to the E.S. Cox Archive. The sketch was made by E.S. Cox in the evenings apparently ‘on the dining room table’ and is a rare item which was preserved almost by accident. Formal designs were probably developed from it by the various railway drawing offices

Laying out the very first concept for a British Railways Standard type locomotive, the sketch depicts an interesting mix up design ideas some of which made it to the final types of Standard locomotive but with it committed to paper for discussion long before anything was finalised.

This sketch seems to note how much longer (in length) the locomotive would have been compared to William Stanier’s Class 5 4-6-0 (Black Five), therefore evidencing an initial plan for a Standard Class 5MT Pacific.

The boiler pressure is shown on the sketch as 225psi, with 18.5” x 28” cylinders and 6’ driving wheels, which basically tally with the principal details of Stanier Class 5s. It also lists several types of valve gear, including Walschaerts, Caprotti and Stephenson – possibly referencing some of the valve gears applied to later batches of the Stanier Class 5 by George Ivatt. In the event, it was decided that there was little inherently wrong with the existing Class 5 4-6-0s, which ultimately formed the basis of an updated Standard Class 5MT 4-6-0 design, and so the 5MT Pacific morphed into what would become BR’s Standard Class 6MT ‘Clan’ Pacific.

The differences between this sketch and BR’s 6MT ‘Clan’ Pacifics as built are indicated by the following. BR’s ‘Clan’, ‘Britannia’ (7MT) and Duke of Gloucester (8P) Pacifics all ended up with 6’ 2” driving wheels (like the Gresley V2s, the Bulleid Pacifics and the Thompson/Peppercorn A2 Pacifics). The Class 6MTs were given two 19.5” x 28” cylinders, while the Class 7MTs had two 20” x 28” cylinders and the 8P had three 18” x 28” cylinders with Caprotti valve gear. Roller bearings were the subject of debate and were not universally fitted, while only the 8P was given a double chimney. Nevertheless, the 6MT retained the 225psi boiler as opposed to the 250psi boilers given to the 7MT and 8P.

Ultimately, only ten Class 6MT ‘Clan’ Pacifics were built with a subsequent batch cancelled, so they weren’t necessarily the most successful of the BR Standards. It would be interesting to know if similar sketches were made for the other classes. Considering Riddles first envisaged the Class 9F 2-10-0 as a 2-8-2, this document is also an interesting example of ‘what might have been’.