NeO6874This is from my phone, so the image isn't so clear ... Looks like the gap is right on the tie. You possibly didn't cut through the rail all the way. Cut through both rails in between the ties (and just fill in with gap-filling ca / styrene / etc)
I did cut all the way through and filled with stryene and the gap was isolating the siding rail, no continuity across the gap with my VOM., I then went back and removed the styrene and checked the gap all the way through the tie strip. I have moved on to another project for now and will go back and remove the entire siding and put a new pc of C83 flex with both rails isolated.
-Bob
Life is what happens while you are making other plans!
Well, I finally got back to the turnout problem: I removed the flex track from the turnout and set it down next to it, not touching, and connected jumpers from both rails on the adjacent siding (that has no problems) to both rails on the flex track and everything worked as it should. Now, I noticed that there is about 3/4" of rail on the turnout from the gap I cut to the end. I touched this piece of rail with the red jumper and it shorted! I removed the 3/4" section of rail and found it had a very thin flat jumper factory soldered (under the tie) which I hadn't noticed before installing the turnout. So, it appears I can go ahead and reinstall the flex siding and everything should be OK. What a journey? Should have tested it all before final soldering and glueing.
Thanks again to all of the suggestions, comments and support.