I have been fighting a battle with the switches for a while now, intermittent derailments, then I picked up a nice Kato Amtrak set with DCC sound. The problem became worse, I first thought one of the switches was bad, I fiddled and fiddled, sometimes no problem, it was always the first car after the loco. This switch fed into a curve or was after the curve depending on the direction of travel. The derailment only occurred going into the curve from the switch a 44859 or 44860 one on either end. Anyway what I found was the tail of the loco swung out going into the curve, and causing the first car to derail. Remedy by adding a short section of straight track between the switch and the beginning of the curve solved the problem. I have done this on all my switches that switch to a curve from the curved part of the switch. No more derailments period, I can run through all the switches at any speed in any direction.   The short cars were hit and miss, the long cars 90% of the time would derail before making the change. I hope this helps someone in the future. All of my switches are the new style with the frogs powered.

just under 6 1/2 inches