4-4-0

A 4-4-0 is a type of steam locomotive. In the Whyte notation, 4-4-0 signifies that it has a two-axle bogie (Am. "truck") to help guide it into curves, and two driving axles coupled by a connecting rod. The 4-4-0 is most commonly known as the American type due to the large number of this type that were produced and used there, but the type subsequently became very popular in Great Britain where large numbers were produced. Almost every major railway that operated in North America in the first half of the 19th century owned and operated locomotives of this type. The famous locomotive named The General was a 4-4-0.

The first use of the name American to describe locomotives of this wheel arrangement was made by Railroad Gazette in April 1872. Before that time, this wheel arrangement was known as a Standard or Eight-Wheeler. This locomotive type was so successful on US railroads that many earlier 4-2-0 and 2-4-0 locomotives were rebuilt as 4-4-0s by the middle of the 19th century.