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.
2-8-0+0-8-2
The London and North Eastern Railway (LNER) owned a single Class U1 Garratt, built by Beyer, Peacock in 1925. It was designed by Nigel Gresley for banking coal trains over the Worsborough Bank, a steeply graded line in South Yorkshire and part of the Woodhead Route. The Class U1 was both the longest and the most powerful steam locomotive ever to run in the United Kingdom.