Under the Whyte notation for the classification of steam locomotives, 4-2-2 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and two trailing wheels on one axle. Other equivalent classifications are: UIC classification: 2A1French classification: 211Turkish classification: 14Swiss classification: 1/4 Like other steam locomotive types with single pairs of driving wheels, they were also known as singles.