2-6-6-2

2-6-6-2

Equivalent classifications UIC class (1C)C1, (1'C)C1' French class 130+031 Turkish class 34+34 Swiss class 3/4+3/4 Russian class 1-3-0+0-3-1

First known tender engine version First use 1906 Country United States Locomotive Class L-1 2-6-6-2[1] Railway Great Northern Railway Designer Baldwin Locomotive Works Builder Baldwin Locomotive Works Evolved from 0-6-6-0,[2] 2-6-6-0[3] Evolved to 2-6-8-0,[4] 2-8-8-2 Benefits Able to follow tighter curve than contemporary 2-10-2 locomotives of similar tractive effort Drawbacks Higher maintenance costs due to a second set of cylinders and valve gear

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-6-6-2 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 locomotive or Golwé locomotive with the same wheel arrangement is designated 2-6-0+0-6-2 since both engine units are pivoting.

Under the UIC classification the wheel arrangement is referred to as (1'C)C1' for Mallet locomotives.