I have found that no matter what the brand freight cars are they have a terrible wabble. This is due to the truck pins not being tight enough . I have solved this problem by removing the truck pins and replacing them with #2 1/4" screws. I tighten the screws down until the truck will not turn, then back it off too allow free lateral(sideways movemen)t. Back it off a little more (each truck is different) until you have just a little up and down truck movement. With the cars weighed too NMRA standards I have found that they are more reliable and less likely to derail.
Virtually all high quality cars will not wobble as delivered from the manufacturer. If they do wobble, it is almost always because of bad trackwork. If the trucks pins aren't pushed in far enough, it's a simple matter (and FREE) to push them back in again.
Ira: Using #2 1/4 screws will create many other problems.. AS Kis said quality cars will not wobble. The problem is with your trackwork. Stay cool and run steam....
