Tom Thumb was the steam locomotive that famously raced a horse on the Baltimore and Ohio Railroad in 1830.
Designed and built by Peter Cooper in 1829, Tom Thumb was the first American-built steam locomotive to operate on a common-carrier railroad. Cooper created it as a demonstration machine to persuade the newly formed Baltimore and Ohio Railroad that steam traction could work on its tracks; it was not originally intended for revenue service.
The celebrated race probably took place near Relay, Maryland, in August 1830, although historical accounts give more than one date. Tom Thumb initially pulled away from the horse-drawn car, demonstrating the potential of steam power. Its victory was spoiled when a belt slipped from the blower pulley, reducing the boiler’s draft and causing the locomotive to lose power. The horse then passed it.
Despite losing the race, Tom Thumb achieved its real purpose. The demonstration helped convince the B&O to adopt steam locomotives, and the railroad moved away from horse power soon afterward. The original locomotive no longer survives, but a working replica is displayed and operated for demonstrations.