My wife and I are currently building a Small Christmas layout using n scale EZ track.  We are at the point of caulking the track to the foam board.  I began testing the oval track and have found a dead spot involving 5 pieces of track, curve, 2straights,then 2 more curves.  The locos I tried both stopped on both sides of these rails. I uses the eraser style cleaner, wiped with alcohol to no avail. I subbed a couple of brand new straight pieces, no luck there. I don't have any curves left to change out. Any suggestions?