"Oliver Evans' 'Oructor Amphibolis,' or, Amphibious Digger, the First American Locomotive--1804"

Inventor and engineer Oliver Evans believed that steam engines, used to power mills and steamboats, could also propel land vehicles. An opportunity to experiment came with a commission from the Philadelphia Board of Health for a steam dredge. Evans designed a 30-foot long, 17-ton amphibious digger that moved successfully over land in 1805. This onetime stunt proved the viability of steam-powered carriages.