Under the Whyte notation system, a steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted on separate frames, one on each end of the boiler, and each having an 0-4-0 wheel configuration.

plural of 0-4-0+0-4-0

Under the Whyte notation, a steam locomotive that has four coupled driving wheels followed by two trailing wheels, with no leading wheels.

plural of 0-4-4

plural of 0-4-2

Under the Whyte notation system, the simplest form of steam locomotive, with two axles and four driving wheels, and no leading wheels or trailing wheels.

Under the Whyte notation, a steam locomotive that has four coupled driving wheels followed by four trailing wheels, with no leading wheels.

plural of 0-4-0

Under the Whyte notation system, a Mallet-type locomotive with no leading truck, two sets of four driving wheels, and no trailing truck.

Under the Whyte notation system, a Mallet-type locomotive with no leading truck, two sets of four driving wheels, and two trailing wheels on a trailing truck.