Mavrick0, I had a spot on one of the staging tracks where, for whatever reason, there was a bump in the track at a joint. I suspect it was track from the old layout that had a vertical curve that didn't go away. The Kato-found issue was essentially the same thing except on one of the mains and not at a joint - it was about a foot in from the end of a stick. These should of course have been spotted during tracklaying but weren't. Simply cutting out the affected part, and some on either side cured the problems. in each case there are now two joints where there had been one.