|This article does not cite any sources. (December 2009) (Learn how and when to remove this template message)|
In railway terminology, a single is a steam locomotive with a single pair of driving wheels. Some sources use 'Single' only for the 2-2-2 type, also known as a Jenny Lind locomotive, but more commonly singles could have any number of leading or trailing wheels.
- Winchester, Clarence, ed. (1936), "Some famous singles", Railway Wonders of the World, pp. 1091–1099 illustrated description of some famous singles