Mainline steam trains in Great Britain
The most famous steam locomotive operating on the British main line is the 1923 built "Flying Scotsman". After being taken into public ownership in 2004, following a decade long refit it returned to mainline service in 2016. The fastest steam locomotive ever built, the 1938 built "Mallard", was also certified for main line operation briefly in the 1980s.
GWR 3700 Class 3440 City of Truro
The GWR 3700 Class steam locomotive No. 3440 "City of Truro" was built in 1903 for the Great Western Railway (GWR) at Swindon Works to a design by George Jackson Churchward. It was partially rebuilt in 1911 and 1915, and renumbered 3717 in 1912. Although it is a point of contention, some believe the locomotive to be the first to attain a speed of 100 miles per hour (160.9 km/h) during a run from Plymouth to London Paddington in 1904.