Unfortunately the solution is to not use MTH Railtrax sectional track. I don't have the problems you face with derailment but have had some engines slide sideways in the switches and short out the track, tripping my circuit breaker. I just don't run this engines anymore. I kind of miss the arcs and sparks from the short through the switch for that engine. :-) :-)
I did grind down the black center track glob in the frog of the switches to minimize the bumping. I never did anything with the guide rails through the switches that allow the trains to slide over enough to cause a vertical bump in their travel. I just recently ground all the plastic track rails and guides down to the level of the rails on all switches. The trains seem to run better (??).
I have way too much invested in the Realtrax to discard it. I just file the poor track rail alignments (both vertical and horizontal) and live with it. The result is acceptable for all but the one tin plate City of Denver which I only use around the Xmas tree. I chose Realtrax because it would allow my desired track layout in my limited space. I'm sorry now.
The MTH experience has been 80% good and 20% bad for all of their products which I have almost exclusively on my layout. The Realtrax is the worst but I have had other problems I easily fixed. I find it annoying that the design of the track and the trains in several case have conflicted. MTH stuff should always run on MTH track but that is not always true, it seems.
LDBennett
