ok, I have taken the whole thing apart and I found the problem, it was indeed the CCA wire.
1 - I removed the breaker from the connection and connected directly to the transformer, that allowed me to get a solid 14v to the distribution block (I had the transformer handle set on 14v). But still 6v or less on the track.
2 - I took the Lionel Terminal wire and another piece of fast track, connected that to the distribution block and I was getting 14v on the track.
3 - I then took the track I had used the CCA wire to and flipped it over, checked it with a multimeter and was getting 6v or less right at the wire connection to the track. I unsoldered those wires from the track, used some 18 gauge wire I had left over from a light I installed and soldered that in. 14v to the track!
4 - I then tried to reinstall the breaker at the transformer and I lost all my volts again at the track. I then removed that and everything was fine again.
The end result, the CCA wire hates being soldered. I did see that @gunrunnerjohn had said that when I was searching the forums last night for help. That seems to be my issue here.
I have the CCA wire now from the transformer to the distribution block, then different wire from there to the track, all seems to be working good. I will use just my postwar / MPC on that track for now until my new wire gets here and I can install that with a breaker. Then I should be able to run both my postwar / MPC stuff and my newer Bluetooth stuff there.
The Common Ground question, I thought on the RW A, B, D, U were common? But I'm guessing they are not all tied together so therefore not "common"? Also, I had read somewhere (link All about the Lionel RW transformer - The Silicon Underground (dfarq.homeip.net)) that C & D give me 10v constant with breaker protection? I'm using those posts for accessories and wanted to get them on a constant voltage, not variable with the track. Should I be connecting A & C instead for accessories and using the 9v constant there? Then do I add another 5amp breaker on that combo? Then is the U & B still ok for the track?
Excerpt from website link above:
"Connecting posts A-C gives 9 volts, B-C gives 6 volts, and B-A gives 3 volts. None of these combinations have circuit breaker protection, so use an external breaker if you use any of these combinations."
