I was super disappointed when I pulled these out of the box and the holes on the articulated part mating up with the pin didn't align well. In addition, the cars were not free rolling. I reamed out the pin hole and changed the wheels to metal wheels and that fixed the issue.

Overall, $90 for each set was a good deal and the detail on the cars is good enough for me. Make these two changes on this and these cars are 100X better than before. I figure I share my solution as I've seen nothing online, and I hope Walthers fixes this issue in the next run due out next month.