Lesson learned today : Do not leave running trains unattended.
A high/low coupler ( something I’ve had happen on real trains as well. ) resulted in my power running into its own train. I almost lost a locomotive into the lake. That wouldn’t have been good. Surprisingly, there was very little damage. I have about six pieces that need to be repaired on the intermodal cars, but the locomotives faired very well. I got lucky this time.
I added a spacer to the coupler, and the rest of the day was uneventful.