Most of you know I ended up with an Athearn Satna Fe passenger set recently. More specificly this one: http://www.ehobbies.com/ath10031.html I want to replace the plastic wheels on the trucks with metal ones. I don't like plastic wheels and I think it makes these otherwise excellent passenger cars look cheap. Can anyone tell me how I find out what size I need to replace them? I've seen 33" wheels, 36" wheels, normal profile, low profile.... It's getting confusing. I figured wheels would be simple but I'm finding out otherwise.