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.
Coronation Scot
The streamlined Coronation Class locomotives were specially developed for the service, and were amongst the most powerful steam locomotives to operate on British railways. On a press run preparatory to the introduction of the service in June 1937, LMS Princess Coronation Class 6220 Coronation, newly built, achieved a speed of 114 miles per hour (183 km/h) near Crewe.