The steam locomotive was not a change that occurred in America in the 1920s.
Steam locomotives first appeared in Great Britain during the early 19th century and was used for railway transport until the middle of the 20th century. The creator of the first steam locomotive was Richard Trevithick, first operated on 21 February 1804, three years after the road locomotive he made in 1801. A steam locomotive is a sort of railway locomotive that produces its pulling power through a steam engine.