Mainline steam trains in Great Britain
The most famous steam locomotive operating on the British main line is the 1923 built "Flying Scotsman". After being taken into public ownership in 2004, following a decade long refit it returned to mainline service in 2016. The fastest steam locomotive ever built, the 1938 built "Mallard", was also certified for main line operation briefly in the 1980s.
Museum of Science and Industry (Chicago)
The "999 Empire State Express" steam locomotive was alleged to be the first vehicle to exceed in 1893, although no reliable measurement ever took place (and such a speed was likely impossible). Designed to win the battle of express trains to the World's Columbian Exhibition, it was donated to the museum by the New York Central in 1962. The locomotive was located outside the museum until 1993, when extensive restoration took place and it was moved indoors as an exhibit in the Transportation Zone.