Here is my ugly, but out sight, American Flyer Billboard.
It is an American Flyer AF 762 two tone whistling billboard. It is out of sight in my mountain, as I had no room on the layout for it. The mountain makes it invisible but the down side is it is not very loud. The AF whistling billboard uses one button for whistle and a second button to operate a solenoid to open a flap to let out air to change the tone.
Charlie