John/Tom - OK - just checked my wiring again and it seems to be wired correctly (as per your diagram). My guess is that it is the insulated track section that is the problem. I have feeder wires going to the track with a hot to the center rail and a common (ground) going to the outer rail THEN I have a wire connected to both outer rails (to ground both rails). I'm going to try insulating both outer rails tomorrow and see if that works - (don't have an ohm meter).
Thanx again -
Paul