4-6-0+0-6-4

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 4-6-0+0-6-4 is a Garratt locomotive. The wheel arrangement is effectively two 4-6-0 ten-wheeler locomotives operating back to back, with the boiler and cab suspended between the two swivelling power units. Each power unit has two pairs of leading wheels in a leading bogie, followed by three coupled pairs of driving wheels and no trailing wheels.

A similar wheel arrangement exists for simple articulated locomotives, but is referred to as 4-6-6-4. On a simple articulated locomotive, only the front engine unit swivels while the rear unit is rigid in relation to the main frame.