Thanks Moonman , I had seen the suggested wire schemes often but never caught that..or forgot...but it makes perfect sense. I've chased serial "echo and loss" before, just not for trains. I've got to wonder how that slipped by Rockstar; I doubt the reason for question was the same now.
If I were to ever order DCS, Barry's book would get here before the TUI. I think I might try to borrow my brothers; someday at least.
I'm still very happy with conventional, but sometimes even happier just learning why one size doesn't fit all.