Just as a quirk to file for possible future reference about derailments:
One of my top ten most dependable scale steam locomotives, a scale Lionel Dreyfus Hudson,
has not left the layout for a decade of running. However, at first, it was very finicky about switches, no matter the manufacturer (Lionel or Ross) and would derail going into the switch and taking the curve outward or , especially, when backing thru one.
I finally figured out what was the cause, by operating the train slowly, with my nose and eyes approx. 1" from the track/switches. It was the wheels on the scale tender, or rather, the shrouding over them. That shrouding would permit the wheels to swing only so-far; any sharper of a turn and the shrouding would force the tender to kind-of lift the locomotive partially off the rails and derail.
Solution? I removed several switches on that route and eventually gave the Dreyfus a switchless route to travel. We have been happy ever since.
FrankM
