Nigel Gresley
Sir Herbert Nigel Gresley (19 June 1876 – 5 April 1941) was an English railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Railway (LNER). He was the designer of some of the most famous steam locomotives in Britain, including the LNER Class A1 and LNER Class A4 4-6-2 Pacific engines. An A1 Pacific, "Flying Scotsman", was the first steam locomotive officially recorded over 100 mph in passenger service, and an A4, number 4468 "Mallard", still holds the record for being the fastest steam locomotive in the world (126 mph).
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 .