Originating in the United Kingdom in the 19th Century, Richard Trevithick is credited with building the first full-scale working railway steam locomotive.  The earliest locomotives for American railroads were imported from Great Britain, but a domestic manufacturing industry was quickly established.

Steam power was one of the most important and key aspects of the Industrial Revolution, Steam locomotives remained a popular method of transportation for a large part of the 19th and 20th century.  

In the United States, the Transcontinental Railroad was completed on May 10, 1869, when the Central Pacific and the Union Pacific Railroad companies combined tracks in Promontory, Utah.  The two companies had agreed to build toward each other.  From agreement to completion workers labored seven years on both sides facing great difficulties and risks to join the two lines.  This monumental feat immediately reduced travel time from the eastern U.S. to the west from what was months to less than a week.