0-6-0

[josaer]

What do the different numbers stand for when referring to a locomotive??

[ABC]

The first number refers to the number of leading (non-drive) wheels, any numbers in the middle refer to the number of drive wheels, and the last number refers to the number of trailing (non-drive) wheels. In the 0-6-0, there are no leading wheels, 6 drive wheels, and no trailing wheels.