Cool.  So, trucks = the thing that screws onto the bottom of the trains that hold the wheels and wheelsets are typically 33"...  Does that mean that the wheels in real-life proportional size is 33"?  Thanks for the link as well!

Can someone help me as to what I need to order to replace the wheel on the thoroughbred set?  My youngest got a hold of it earlier and I see there are two wheel sets - 33" and 36".  However, those measurements make no sense to me because it is about an inch and a half...  The wheels are for a cargo car...  Also, can you buy the entire wheel set that swivels?  It looks like there is one small screw holding them in, but I did not see the entire wheel set on the site...