@gunrunnerjohn posted:I honestly can't say, but I'm guessing the round top of Fastrack, I don't what else it could be. I know it cruised around my Fastrack in the old house without a problem, and that was on carpet! When I put it on better track in a laser-leveled layout, it derailed on almost every curve! BTW, the curves are O72 and larger as well.
Seems like a lot of mysteries associated with this hobby John. 
If the Cargraves /Ross tracks are flat maybe you are right . The Fastrack being round top might allow a little more tolerance in wheel movement from side to side and being round it could let the flanged wheels slip down inside the rail easier . 
Whatever the case , your solution for your new track was really pretty nice..........one of these days I'm going to have to get a small wheel puller.
Thanks for sharing.
