Well...................... on the hopper cars, you might want to cut the plastic stirrups off (4 of 'em), they tend to interfere with the truck swing. And, you may have to cut or shave off a small plastic protrusion on the hopper body, both sides, at each end, for the exact same reason (on the body frame, right above the truck bolster). Fortunately, they're quite small and not very noticeable to start with.
These hopper cars have metal trucks on them. Occasionally you might get one with an axle popped out of place, or some other minor problem. I have got a few cars that way, but I fix them myself. Haven't run into one yet that I couldn't fix. Or Menard's will make good on them, if you are unable to fix yourself.
The hopper cars are also fairly light, you may want to add some weight to them. But you don't necessarily have to. Overall, I'd say they're a fairly good value for the money, even if you have to trim a little plastic right from the start.
