Have the new 21" 20th Century cars and many of them have trucks that are rubbing against the bottoms of the cars, causing the car to not run smoothly and the locomotive to struggle (wheel slip).
You can see in the picture that the trucks have scraped the plastic on the bottom of the cars and continue to catch there as the cars roll along.
Is there a trick for adjusting the trucks so they do not come into contact with the bottom of the cars?
Many thanks!