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.
Prussian G 5.1
The Prussian Class G 5.1 steam engines were the first 2-6-0 goods locomotives in Europe. They were developed for the Prussian state railways from the Class G 4 and a total of no less than 268 units of this class were placed in service in Prussia between 1892 and 1902. The twin-cylinder G 5.1 had been designed to raise the speed of goods trains on main lines. In addition, more powerful engines were needed for the increasingly heavy train loads. The locomotives, which were equipped with a compressed air brake, were used in charge of fast goods trains ("Eilgüterzugdienst") and also passenger trains due to their impressive top speed of 65 km/h. The G 5.1 was fitted with inside Allan valve gear and the carrying wheels were of the Adams axle design.