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The British Railways Standard Class 9F 2-10-0 is a class of steam locomotive designed for British Railways by Robert Riddles. The Class 9F was the last in a series of standardised locomotive classes designed for British Railways during the 1950s, and was intended for use on fast, heavy freight trains over long distances. It was one of the most powerful steam locomotive types ever constructed in Britain, and successfully performed its intended duties. The class earned a nickname of 'Spaceships', due to its size and shape. In profile daylight can be seen between the frames and the boiler.

At various times during the 1950s the 9Fs worked passenger trains with great success, indicating the versatility of the design, sometimes considered to represent the ultimate in British steam development. Several experimental variants were constructed in an effort to reduce costs and maintenance, although these met with varying degrees of success.

The total number built was 251, production being shared between Swindon (53) and Crewe Works (198). The last of the class, 92220 Evening Star, was the final steam locomotive to be built by British Railways, in 1960. Withdrawals began in 1964, with the final locomotives removed from service in 1968. Several examples have survived into the preservation era in varying states of repair, including Evening Star.

Background[]

The British Transport Commission had proposed that the existing steam locomotive fleet be replaced by both diesel and electric traction. However the board of British Railways, which wanted the railways to be completely electrified, ignored the BTC and ordered a new fleet of 'standard' steam locomotive designs as an interim motive power solution ahead of electrification. Freight was well catered for in terms of locomotive availability after nationalisation in 1948, with a number of heavy freight locomotives built to aid the war effort forming part of British Railways' inheritance. This consisted of 666 LMS 8F class 2-8-0 and numerous Robert Riddles designed WD Austerity 2-8-0s and WD Austerity 2-10-0s.

It was the Eastern Region's Motive Power officer, L.P. Parker, who made the case for a new design of powerful freight locomotive, able to shift heavy loads at fast speeds in round trips between distant destinations within the eight-hour shift of the footplate crew. Riddles took up the challenge, initially designing a 2-8-2 locomotive, but settled upon the 2-10-0 wheel arrangement for the increased traction and lower axle load that five coupled axles can provide. The resultant design became one of the most successful locomotive classes ever constructed in Britain.

Franco-Crosti Boiler Versions[]

Main article: BR Standard Class 9F (Franco-Crosti Boiler System).

Ten locomotives (numbers 92020-92029) were built in 1955 with the Franco-Crosti boiler. which incorporated a combustion gas feed water preheater that recuperated low-grade residual heat. In the 9F version, this took the form of a single cylindrical water drum running along the underside of the main boiler barrel.

The standard chimney on top of the smokebox was only used during lighting up. In normal working the gases went through firetubes inside the preheater drum that led to a second smokebox situated beneath the boiler from which there emerged a chimney on the right-hand side, just forward of the firebox.

In the event, the experiment did not deliver the hoped-for benefits, and efficiency was not increased sufficiently to justify the cost and complexity. Moreover, conditions were unpleasant on the footplate in a cross-wind, this in spite of the later provision of a small deflector plate forward of the chimney. These problems led to the subsequent removal of the preheater drum, although the locomotives did retain the original main smokebox with its distinctive look.

In Fiction[]

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