About: 2-6-6-2

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a is a locomotive with one pair of unpowered leading wheels, followed by two sets of three pairs of powered driving wheels and one pair of trailing wheels. The wheel arrangement was principally used on Mallet-type articulated locomotives, although some tank locomotive examples were also built. A Garratt type locomotive with the same wheel arrangement is designated 2-6-0+0-6-2. Under the UIC classification the wheel arrangement is referred to as (1'C)C1' for Mallet locomotives.