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.
Tom Thumb (locomotive)
Tom Thumb was the first American-built steam locomotive to operate on a common-carrier railroad. It was designed and constructed by Peter Cooper in 1830 to convince owners of the newly formed Baltimore and Ohio Railroad (B&O)(now CSX) to use steam engines; it was not intended to enter revenue service. It is especially remembered as a participant in an impromptu race with a horse-drawn car, which the horse won after "Tom Thumb" suffered a mechanical failure. However, the demonstration was successful, and the railroad committed to the use of steam locomotion and held trials in the following year for a working engine.