2-4-4-2

In Whyte notation, 2-4-4-2 refers to a railroad steam locomotive that has two leading wheels followed by four coupled driving wheels, a second set of four coupled driving wheels, and two trailing wheels.

Other equivalent classifications are:

UIC classification: 1BB1 (also known as German classification and Italian classification)

French classification: 120+021

Turkish classification: 23+23

Swiss classification: 2/3+2/3

The UIC classification is refined to (1'B)B1' for a Mallet locomotive.

This articulated wheel arrangement was rare in North America. Most were built as logging locomotives, presumably to better negotiate the uneven (and often temporary) trackwork that characterized such operations. The added mechanical complexity was found to be of dubious value, as reflected in their limited production and use.cite book| author=LaMassena, Robert| title=Articulated Steam Locomotives of N. America| publisher=Sundance| year=1982| id=ISBN 0913582093| pages=page 7 ]

References