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.
LNER Class A3 4472 Flying Scotsman
While the Great Western Railway locomotive "City of Truro" had previously been unofficially timed at running in excess of , 4472 became the first steam locomotive to be officially authenticated at this speed on 30 November 1934, driven by Bill Sparshatt and running a light test train. It earned a place in the land speed record for railed vehicles; the publicity-conscious LNER made much of the fact.