4-10-0

Under the Whyte notation for the classification of steam locomotives, a 4-10-0 locomotive has four leading wheels followed by ten driving wheels, with no trailing wheels. Central Pacific Railroad's "El Gobernador", built in 1883, was the only locomotive with this wheel arrangement to operate in the United States. The name "Mastodon" has also been applied to this type, though this nickname has also been used for the 4-8-0 arrangement (Mastodon was the unofficial nickname of the Central Pacific's No. 229, the first 4-8-0 ever built), leading to some confusion.

Other equivalent classifications are:

UIC classification: 2E (also known as German classification and Italian classification)

French classification: 250

Turkish classification: 57

Swiss classification: 5/7