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.
Lombard Steam Log Hauler
Alvin Orlando Lombard was a blacksmith building logging equipment in Waterville, Maine. He built 83 steam log haulers between 1901 and 1917. These log haulers resembled a saddle-tank steam locomotive with a small platform in front of the boiler where the cow-catcher might be expected. A steering wheel on the platform moved a large pair of skis beneath the platform. A set of tracked vehicle treads occupied the space beneath the boiler where driving wheels might be expected. The locomotive cylinders powered the treads through a gear train. The log haulers mechanically resembled 10- to 30-ton snowmobiles with a top speed of about .