On May 24, 1830, the first train service in the United States commenced in Baltimore, Maryland. Lucius Stockton's horses pulled these train carriages, but Peter Cooper believed he could invent a steam locomotive that could go faster than a horse. On August 22, Cooper put the first American-made locomotive, Tom Thumb, on the tracks. Stockton and Cooper agreed to a horse versus steam engine race. Not So Fast, Tom Thumb tells the story of one of the most remarkable and surprising contests in American history.