Been chewing on this one for a while. My Korber roundhouse is just about finished and I'm getting close to start applying the scenic features around it and the whisker tracks so I put this idea on the back burner for the time being.
My stepson works for a company that engineers and programs machine automation for CNC, robotics and other manufacturing equipment. After looking at what I have in mind he said it would be easy peasy with an Arduino and servos motors. I found this video on YouTube that looks promising. I don't care for the location of the servo but I like the concept.