John - I won't be running the ZW. I plan to trade it in on a refurbished ZW. I'll use a Z in its place temporarily (with a careful eye on the voltage settings) till I get the replacement ZW.
Alan - Here's what my insurance agent brother said about coverage.
I know of no reason, other than arson, that an insured would deny a claim when the damage was caused by an electrical device.
However, there might not be coverage for the electrical device itself.
I guess you can keep your trains…