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.
British Rail Class 91
A Class 91, 91010 (now 91110) holds the British locomotive speed record at , set on 17 September 1989, just south of Little Bytham on a test run down Stoke Bank with the DVT leading. Although Class 370s, Class 373s, and Class 374s have run faster, all are EMUs, which means that the "Electra" is officially the fastest locomotive in Britain. Another loco (91031, now 91131), hauling five Mk4s and a DVT on a test run, ran between London King's Cross and in 3 hours, 29 minutes and 30 seconds on 26 September 1991. This is still the current record. The set covered the route in an average speed of , and reached the full several times during the run.