LNER Class A4 4468 Mallard
London and North Eastern Railway locomotive numbered 4468 "Mallard" is a Class A4 4-6-2 Pacific steam locomotive built at Doncaster Works, England in 1938. It is historically significant as the holder of the world speed record for steam locomotives at .
Milwaukee Road class A
They hauled the fastest scheduled steam-powered trains in the world. Running at 100 mph or greater was required to keep these schedules; the class A locomotives were designed to cruise at over and be able to achieve . A run with a dynamometer car behind the locomotive was made on May 15, 1935 by locomotive No. 2 between Milwaukee and New Lisbon, Wisconsin. Over a stretch the speed of was recorded. This was the fastest authenticated speed reached by a steam locomotive at the time, making No. 2 the rail speed record holder for steam and the first steam locomotive to top . There are reports, without evidence or accurate records, that these locomotives could exceed . Such speeds would have placed the class A in contention with the LNER Class A4 and German BR 05 for the crown of fastest steam locomotive until that time, but no records have been unearthed. The successor Milwaukee Road class F7 was even more powerful, with a claimed top speed of .