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.
Saint Paul Union Depot
The "Morning Hiawatha" may have held the record as the world's fastest steam train on two or more measures: The run from Sparta to Portage, Wisconsin was scheduled for 58 minutes—an average of . Speeds up to and above were achieved on a daily basis, and the powerful Milwaukee Road class F7 engines (designed for a "reserve speed" of ) likely ran more miles at or above than any other steam locomotives in history.