Whyte notation

widely used description of wheel arrangement using numbers of carrying, driving and carrying wheels listed front to rear.  Certain common arrangements are referred to by names, e.g. Atlantic 4-4-2, Baltic 4-6-4, Consolidation 2-8-0, Mikado 2-8-2, Mogul 2-6-0, Pacific 4-6-2, Prairie 2-6-2 and so on.