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.
Museum of Science and Industry (Chicago)
The "999 Empire State Express" steam locomotive was alleged to be the first vehicle to exceed in 1893, although no reliable measurement ever took place (and such a speed was likely impossible). Designed to win the battle of express trains to the World's Columbian Exhibition, it was donated to the museum by the New York Central in 1962. The locomotive was located outside the museum until 1993, when extensive restoration took place and it was moved indoors as an exhibit in the Transportation Zone.