I had an idea when I saw this ball head mount in a Goodwill auction.

I've been using a GoPro suction clamp mount to mount cameras on my LGB train for on-board videos, but it isn't what I call camera aiming friendly.
I won the auction and got about to mounting the ball head to a piece of plexiglass that would fit in the compartment of a freight car I was given last year.
It works pretty well now that I've got the balance worked out. The camera needs to be in the center of the car or it will cause it to derail going around a corner.
Works well and is pretty stable too.