It was one of the most powerful steam locomotive types ever built for British Railways, and successfully performed its intended duties.

[2] 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.

"[5] The British Transport Commission had proposed that the existing steam locomotive fleet be replaced by both diesel and electric traction.

[7] The 9F was designed at both Derby and Brighton Works in 1951 to operate freight trains of up to 900 tons (914 tonnes) at 35 mph (56 km/h) with maximum fuel efficiency.

[6] The original proposal was for a boiler from the BR Standard Class 7 Britannia 4-6-2, adapting it to a 2-8-2 wheel arrangement [8]: 52  but Riddles eventually settled upon a 2-10-0 type because it had been used successfully on some of his previous Austerity locomotives.

Ten locomotives (numbers 92020-92029) were built in 1955 with the Franco-Crosti boiler[8]: 46 [10] which incorporated a combustion gas feed water preheater that recuperated low-grade residual heat.

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.

These problems led to the subsequent removal of the preheater drum, although the locomotives did retain the original main smokebox with its distinctive look.

[14] Locomotive numbers 92165–92167 were built with a mechanical stoker, which was a helical screw that conveyed coal from the tender to the firebox, where it would be directed to the required part of the grate by high-pressure steam jets controlled by the fireman.

[7] The stoker made higher steaming rates possible, and it was hoped that mechanical stoking might enable the burning of low-grade coal.

After the completion of the tests in February 1958, it was decided to fit all 9Fs built subsequently with double blastpipes and chimneys — they were numbers 92183 onwards, as well as 92165–7.

[7] The 9F turned out to be the best of the Standard classes, and one of the finest steam locomotives ever designed in Britain in terms of its capacity to haul heavy loads over long distances.

[7] It was highly effective at its designed purpose, hauling heavy, fast freight trains, and was used all over the British railway network.

[15] The 9F also proved its worth as a passenger locomotive, adept at fast running despite its small driving wheels, and for a time was a frequent sight on the Somerset and Dorset Railway,[7] where its power and high proportion of adhesive weight were well suited to coping with the 1 in 50 ruling gradient on the Bath extension.

On one occasion, a 9F was set to haul an express passenger train, in place of the normal LNER pacific, from Grantham to King's Cross.

[19] Like other primarily goods locomotives, British Railways' fleet of 9Fs also saw extensive passenger service in hauling Saturday 'Holiday Specials', especially in the North East and Western regions.

92220 was named Evening Star and turned out in British Railways Brunswick Green livery, which was usually reserved for express passenger locomotives.

92220, bore a blue spot on the cab side below the number, to denote the axle loading under the former GWR's system of weight classification.

[8]: 72 Nine Standard Class 9F 2-10-0 tender locomotives survived withdrawal from mainline service into preservation: Evening Star became part of the National Collection; eight others were bought directly from BR or from Woodham Brothers scrapyard in Barry, South Wales.

Due to the engines' flangeless centre driving wheels, there is a concern that the raised check rails on modern pointwork might cause a derailment, so the class (alongside other 2-10-0 locomotives) is currently[timeframe?]