2-2-2-0

Under the Whyte notation for the classification of steam locomotives, 2-2-2-0 usually represents the wheel arrangement of two leading wheels on one axle, four powered but uncoupled driving wheels on two axles, and no trailing wheels, but can also be used to represent two sets of leading wheels (not in a bogie truck) two driving wheels, and no trailing wheels. Some authorities place brackets around the duplicated but uncoupled wheels, creating a notation 2-(2-2)-0, or (2-2)-2-0, as a means of differentiating between them. Others simply refer to the locomotives 2-2-2-0.