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 built for British Railways, and successfully performed its intended duties. The class was given the nickname of 'Spaceships', due to its size and shape.

Nine 9F 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. Only six members of the class have been restored to running order. 92240 was the first of the class to steam in preservation after restoration work in 1990. Engines from both builders have survived with three Crewe-built engines and six Swindon-built engines. The majority of the class have double chimneys but 92134 is fitted with a single chimney.