What was the name of the first U.S.-built steam locomotive?

“Tom Thumb”, built by Peter Cooper in 1830, was the first U.S.-built steam locomotive to operate on a common-carrier railroad and was developed to convince owners of the newly formed Baltimore and Ohio Railroad (B&O) to use steam engines. B&O is now CSX, a Class I freight railroad operating in the eastern United States and the Canadian provinces of Ontario and Quebec.

The engine was built by Peter Cooper as a four-wheel locomotive with a vertical boiler and vertically mounted cylinders that drove the wheels on one of the axles. The "design" was characterized by a host of improvisations. The boiler tubes were made from rifle barrels and a blower was mounted in the stack, driven by a belt to the powered axle. The engine was fuelled by anthracite coal.

“Tom Thumb” was involved in a race with a horse-drawn car, which the horse won because of engine mechanical failure. However, the demonstration was successful, and B&O committed to future use of steam locomotion to replace horsepower - good news for Cooper whose substantial real estate investment in what is now the Canton neighbourhood of Baltimore would increase in value significantly.

Because “Tom Thumb” was built as a ‘demonstrator’ the original was lost but a replica remains on display at the B&O Railroad Museum. The museum lists the replica as "operational", and the locomotive makes special appearances each year.

The “Stourbridge Lion” was the first steam locomotive imported into the U.S. from England in 1829.