Great Western, King Class 4-6-0s: From Construction to Withdrawal

By David Maidment

An in-depth look at the British railway company’s celebrated class of steam locomotives, with more than three hundred photos.

Built by Collett in 1927 after pressure to restore the Great Western Railway’s pre-eminence in motive power and cope with increasing postwar traffic to Devon and Cornwall holiday resorts, the thirty Kings were the final development of the Churchward Stars and the 1923 Castles and remained on top-link main line duty until their final replacement by the ‘Western’ class 52 diesel hydraulics in 1962.

This book includes an insight into the thinking of some of Collett’s senior staff at the end of the 1930s and the eventual transformation in the latter years with redraughting and double chimneys. As well as describing their design and construction, the book comprehensively covers their operation and performance, backed up by many recorded logs on all main GW/WR routes over which they were permitted. The author had close experience of the class when working at Old Oak Common between 1957 and 1962, and includes a chapter of his experiences with them, including many footplate trips (as a management trainee, he was greeted with glee by firemen who would hand him the shovel). The book also includes over 300 photographs, one hundred of them in color.

• Language: English
• Publisher: Open Road Integrated Media
• Release date: Aug 30, 2020
• ISBN: 9781526739865

David Maidment

David Maidment was a senior manager with British Railways, with widespread experience of railway operating on the Western and London Midland Regions culminating in the role of Head of Safety Policy for the BRB after the Clapham Junction train accident.He retired in 1996, was a Principal Railway Safety Consultant with International Risk Management Services from 1996 to 2001 and founded the Railway Children charity (www.railwaychildren.co.uk) in 1995. He was awarded the OBE for services to the rail industry in 1996 and is now a frequent speaker on both the charity.

Book preview

Chapter 1

DESIGN AND CONSTRUCTION

Collett was faced with a challenge – to design and build a powerful express locomotive capable of taking increased loads to the South Devon and Cornish resorts by the summer timetable of 1927, barely a year away. And it had to have a calculated tractive effort of over 40,000lbs to meet the directive of the GWR Board. There was insufficient time to design a locomotive with too many innovations because of the time that would be required by the drawing office staff and any major adjustments or new tooling required in the Works. There was one major step forward, however. Sir Aubrey Brocklebank, the powerful chairman of the company’s Locomotive Committee, had persuaded the Civil Engineer to increase the axleload limitations to 22½ tons, with instructions to bring the remaining bridges on the West of England main line up to the required standard by June 1927. In fact, the majority of bridges replaced on the line over the previous twenty or so years had been designed to carry 22 ton axleloads but the secretive civil engineering department had omitted to tell anyone!

Because of time constraints, Collett did not pursue a pacific design option, despite the comparison with the LNER pacifics encountered in the 1925 Exchange. Perhaps he was influenced in any case by this trial as the smaller GW engine had demonstrated its apparent superiority. Perhaps the increased adhesion of a 4-6-0 over a pacific influenced him also, as good adhesion would be a vital factor to increase loads over the South Devon banks to avoid much costly double-heading. The GW still had the experience of the less than successful pacific The Great Bear in its psyche – Collett had only authorised its conversion to a Castle a couple of years previously. The publicity people may have wanted to replace that former ‘prestige’ locomotive, but a pacific in itself was no longer newsworthy. Collett had already rejected the Hawksworth/Stanier proposal for a compound Castle with a potential tractive effort of 35,700 lbs, a complexity he did not support and in any case, not powerful enough.

Collett therefore took his Castle design as the basis and sought to see how its power could be increased to meet the specification. The axleload relaxation would allow for a much heavier boiler, such as the 4700 class No.7 boiler that Churchward had earlier been denied for his proposed ‘Super-Star’. The boiler, to be designated as Swindon’s No.12 standard boiler, was lengthened from the Castle’s and Star’s 14ft 10in to 16ft (though still 7ft shorter than that of The Great Bear). The diameter was increased by 5in at the front and 3in at the rear over that of the Castle – identical to that of the former No.111. The long narrow firebox was extended by a significant 18 inches, and the boiler pressure was increased from 225 to 250lbs psi. The grate area was increased from 29.4 to 34.3sqft. The Swindon No.3 superheater with just 84 elements was modestly increased to 96, giving a total area of just 313sqft. The total heating surface including tubes, firebox and superheater was raised from the Castle’s 2,284 to 2,515sqft. The larger size and boiler pressure would increase the tractive effort by a nominal 3,980lbs, the most significant step towards the desired power capability.

The second design element that would determine the tractive effort was the cylinder size and arrangement. The cylinder diameter was increased from 16 to 16¼in, increasing the tractive effort by a theoretical 990lbs and the stroke increased from 26 in to 28in, giving a further 2,560lbs power output. In fact only the first six locomotives, 6000-6005, were built with these cylinder dimensions. Thereafter, the cylinder diameter reverted to 16in, which meant that only those first six locomotives met the 40,000 tractive effort criteria, though this was enough for the GWR’s publicity