4-8-2 and 4-6-? what does it mean?

[pamardon]

what does those numbers mean??

i see that a lot in here but I'm clueless 

[the Bach-man]

Dear Pam,
the numbers indicate the wheel arrangement of the steam locomotive. A 4-8-2, called a "Mountain", has four wheels on the front (pony) truck, eight drivers, and two wheels on the trailing truck.
See:
http://www.steamlocomotive.com/misc/wheels.shtml
Happy Holidays!
the Bach-man