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.
Steam locomotive
For a short period after the war, both Bundesbahn (DB) and Reichsbahn (DR) still placed orders for new steam locomotives. They needed to renew the rolling stock, mostly with steam locomotives designed for accelerated passenger trains. Many of the existing predecessors of those types of steam locomotives in Germany had been lost in the battles or simply reached the end of their lifetime, such as the famous Prussian P 8. There was no need for new freight train engines, however, because thousands of the Classes 50 and 52 had been built during the Second World War.
Because the concept of the so-called "Einheitslokomotiven", the standard locomotives built in the 1920s and 1930s, and still in wide use, was already outdated in the pre-war era, a whole new design for the new steam locomotives was developed by DB and DR, called "Neubaudampflokomotiven" (new-build steam locomotives). The steam locomotives made by the DB in West Germany, under the guidance of Friedrich Witte, represented the latest evolution in steam locomotive construction including fully welded frames, high-performance boilers and roller bearings on all moving parts. Although these new DB classes (10, 23, 65, 66 and 82) were said to be among the finest and best-performing German steam locomotives ever built, none of them exceeded 25 years in service. The last one, 23 105 (still preserved), went into service in 1959.