How are trucks, and couplers attached?

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

I have been looking around the internet trying to find some pictures of the bottom of rail cars. I have found one halfway decent image of a boxcar on it's side, but the trucks are gone. Ok this one is usable, kind of, it was taken so far away no real detail is visible.
Here is what I am doing, I am making some railroad, buildings, cars bridges etc. using Google SketchUp. The amount of data available online is surprisingly limited. Anybody here have a link to the ultimate resource, for railroad stuff? is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to