Managed to coax two of the grandkids away from their computer games long enough to reach the milestone of operating two trains simultaneously on the layout. Had de-rails on the curved turnout. I caught the left front wheel on the lead truck climbing the rail like this. Couldn't find anything on the rail, but after checking all four wheels of the lead truck, I found that the right rear wheel was dropping in a depression at the frog. The floor (name?) was too low allowing it to drop and lifting the opposite side. Reminds me of adjusting race car chassis... I added a new "floor" to help.
Well done on all counts! "Wheel drop": From what I understand it can be a common issue with model track products. You seemed to have solved the problem by decreasing the depth of the flange way at the frog. Good job! Hopefully, your grand kids enjoyed the experience?
On all of my Peco switches I added a .015 shim to the outside guard rails to help keep the flanges from picking the frog point. Not a single problem since. I think I used .015 x .060 styrene strips from evergreen and just plastic glue cemented In place, painted with micromark neolube
