Today I noticed that some certain rolling stock I have that there is some friction when going through the turns. I guess it became really noticeable for me when I really loaded down my simple DCC engine and put every car I have on it, plus a new Athern Genesis 60' Hi-Cube boxcar. Now, I just have a simple oval sitting on a 5'X9' or so rug, but I finally figured out that rolling stock that has a wide 'spine' on the bottom of the car will have wheels that rub the spine on the turns. I have EZ-Track. So, what's the problem here? I haven't noticed that the EZ-Track I have is some super tight stuff.
Kelly, I suspect your E-Z Track is 18" radius. I use 18" radius curves in many places on my layout but I restrict them to 40 and 50 foot freight cars. Long cars can cause problems on these tight curves.
The solution is to either use larger radius curves or to carve away a bit of the centre sill where the wheels touch it.