I’m building a really small N Scale track layout. I have the track all down on cork roadbed and wired. Its an up and over figure eight with 3 switches down on the ground under the crossover. One of my quesions concerns the track insulators. When using track insulators a space is on the other track, due to the plastic spacer on the insulator. I notice when the locomotive crosses these spaces a slight bumping noise occurs as the wheels of the train cross that slight space. Is there anything that needs to be done here, or is that too small a space to worry about?
Question number 2 is about the train car wheels. I have some old cars that have what looks to be larger metal wheels than the newer cars I just bought. Can these differing sized truck wheels cause derailment problems? (I’m on N scale 80 track) I have some extra replacement trucks with the smaller wheels but some of them seem to be metal and some plastic. I’ve played around with exchanging the wheels and trucks, but should there be a reason for the larger metal (old style) wheels to cause problems?