HO engine numbers

[NLH]

I am a new owner and I would like to know what the different numbers (usualy separated by dashes) mean.
Thanks,
NLH

[Len]

If you're talking about steam locos the numbers represent the wheel arrangement of the loco, e.g., 4-6-2 would mean a 4-wheel pilot truck, 6 driving wheels, and a 2-wheel trailing truck. A loco with a 4-6-2 wheel arrangement is generally known as "Pacific".
This identification system was developed by Fredrick Whyte.

More info on the system can be found at: http://en.wikipedia.org/wiki/Whyte_notation

Len