I have a very large and complex layout, lots of parallel tracks, multiple decks, etc. I use Gargraves track with all of the rails insulated for detection. I recently completed the addition of .1u capacitors to get TMCC signal on both rails.
I have a growing fleet of Lionel and Atlas diesels. Most of them make it around with no trouble, but a few are driving me nuts. I just got one back from the local service station. I was told it was reprogrammed and it was fine. Put it on the track at home, and the lights just flicker. I place my hand over it, and it works fine. I have a few of these, and would love to find a real fix.
Fortunately, my hair is too short to get a good grip on.