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.
2-8-4
Two prototypes were built in two-cylinder and three-cylinder versions. When tested, the two-cylinder version proved to be superior to the three-cylinder Class 114 version, and eventually twelve more two-cylinder Class 214 locomotives were built. In 1936, no. 214.13 reached a speed of , the highest speed ever attained by an Austrian steam locomotive. The regular speed limit was .
From 1938, the Deutsche Reichsbahn (DRB) designated the locomotives class 12.0. In the summer of 1939, they hauled 600 tons express trains out of Vienna over Wienerwald at a speed of , reaching over level stretches.