After many frustrating hours, I think I may have made some progress last night with the switch that the NS loco is struggling with. I first tried messing around with some of the switch parts (guardrails, etc.) to no avail...nothing seemed to be wrong with the loco, wheel trucks, etc. So I decided to try a layout revision that allowed a 3.5" straight piece between the O31 curve and the switch thinking if it was going straight into the switch that would clean it up...seemed to help on the first pass, then clunked thru the 2nd pass, then off and on clunking thru and sometimes still getting hung up...so a little better but not even close to acceptable...to make matters worse, now it was clunking thru another switch with no curves. Beyond frustrated at that point I went to the gym to clear my head. Came back and it dawned on me...what if I'm looking at this all wrong...what if I should be looking at this in the vertical plane and not just the horizontal plane? So I cut some thin foam shims (varied from 1/32" to 1/8") and started playing around with shimming up track in various places around the switches to level things up. It worked! I ran the NS loco around the entire layout in all directions multiple times and didn't get hung up once...even went thru the switches a little smoother!
Haven't had a chance to get into the other one that doesn't throw to the outer rail properly yet...that one will have to wait but when I have time I'll take it apart to check that wire and will likely add another power feed near it to beef that up.
Still a lot bumping around the layout due to the bad rail connections of this Realtrax stuff but I'll keep working to clean that up over time.
In hindsight I doubt that I would buy this MTH Realtrax stuff if I had it to do over again but I have way too much time and money invested in this so not giving up...at least Christian should now be able to run his trains for Christmas.
Thank you everyone for your input...much appreciated as always!