Having seen how much people like pushing buttons for certain accessories, I have been adding some animations. I really like my Marx Freight Terminal. I added lights and an REA sign a while back. Now the terminal has people that move in and out. The people are fastened to a semicircular base that is attached to a servo motor. The base is made to match the station floor (printed the pattern and glued it the the semicircular base). The servo motors are disguised as luggage. The servos are attached with one tiny screw through the floor and a strong magnet on the side.
An arduino nano controls the servo motor based on input from pushbuttons and IR sensors. There are two sets of people and two buttons for manual control. Push the button, the people come out, push it again, they go back in. I already had two IR sensors to control a gateman, so I hooked those up the arduino controlling the station people. The first sensor makes one set of people go in and the other come out. The second sensor does the opposite. The idea is to have people getting on and off the train. The people are getting pretty good at getting on and off even when the train doesn't stop!