Where do I find replacement parts?

So recently I was blindly taking apart a HiT era TrackMaster Thomas and I didn't know how to take the wheels off and the wheel broke into 2 pieces. Is there anywhere where I can buy some replacement parts? Maybe even an STL so I can 3d print some new ones?


P.S. How do I take these wheels off without using any fancy tools like a vice so that this doesn't happen again?