Whyte notation

Etymology
Devised by Frederick Methvan Whyte; came into use at the start of the 20th century.

Noun

 * 1) A notation for classifying steam locomotives by their wheel arrangement. For example, a locomotive with two leading axles (four wheels) in front, then three driving axles (six wheels) and then one trailing axle (two wheels) is denoted 4-6-2.