The National Iron & Steel Heritage Museum
4-4-0 American Type

American railroad engines were initially designed from British templates. As designers tweaked the engines for the American landscape, certain engines took precedence. One such engine was the 4-4-0 American Type, which more than any other steam locomotive design for the flourishing of the railroad in the second half of the 19th century.

The most distinctive features of the 4-4-0 is its horizontal boiler and upright steam stack, which differed from other early engines. These features became standard for engines to come, providing a reliable, quality design. The engine was extremely popular, and by 1870 over 75% of all operating steam locomotives used the design. Due to the thousands of 4-4-0s that have been produced over the years, even today a few are preserved or are in operation.