A couple of folks have PM'd me to ask about "what's an F7?" and What do the numbers mean when you say 4-8-2 etc.
4 leading wheels 2 each side (small ones right behind the so-called cow-catcher). These actually steer the locomotive around corners
8 Drive wheels
2 more small ones under the cab
The truly humongous ones were the Union Pacific Big Boys which were 4-8-8 4 and the Challengers which were 4-6-6-4 with two sets of pistons/drivers per side.
For a pic of an F7, check out this Wikipedia: Wikipedia, the free encyclopedia
and for a pic of the Mountain Class that pulled passenger trains when I was a little munchkin : CN U-1-f - Wikipedia, the free encyclopedia
And for those who wondered about my Dad's trailer
When I was growing up, the town had no services such as welders, etc, so my dad went to the nearby town of Roseau, Minnesota to have a trailer built. The guy who did it was experimenting with self-propelled toboggans like the ones he had heard that Armand Bombardier was making in Quebec. He later went into production of them, under the name Polaris. Polaris Snowmobiles, Polaris ATVs and Victory Motorcycles are the result - all "descendents of" my dad's utility trailer which I now own.