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.
History of rail transport in Great Britain to 1830
Trevithick built a third locomotive in 1808, "Catch Me Who Can", which ran on a temporary demonstration railway in Bloomsbury, London. Members of the public were able to ride behind at speeds up to . However, it again broke the rails and Trevithick was forced to abandon the demonstration after just two months.
The first commercially successful steam locomotive was the twin cylinder "Salamanca", built in 1812 by John Blenkinsop and Matthew Murray for the gauge Middleton Railway. Blenkinsop believed that a locomotive light enough to move under its own power would be too light to generate sufficient adhesion, so he designed a rack and pinion system for the line. This was despite the fact that Trevithick had demonstrated successful adhesion locomotives a decade before. The single rack ran outside the narrow gauge edge-rail tracks and was engaged by a cog-wheel on the left side of the locomotive. The cog-wheel was driven by two cylinders embedded into the top of the center-flue boiler. Four such locomotives were built for the railway, and they worked until the early 1830s.