Milwaukee Road class F7
The F7s are major contenders for the fastest steam locomotives ever built, as they ran at over daily. One run in January 1941 recorded by a reporter for "Trains" magazine saw achieved twice—in the midst of a heavy snowstorm. Baron Gérard Vuillet, a French railroading expert, once recorded a run between Chicago and Milwaukee where the locomotive reached and sustained an average for . However, the British locomotive LNER Class A4 4468 "Mallard" is officially accepted to be the world's fastest, with a run recorded at but authenticated at 126 mph in 1938.
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.