Add a basic chug sound to your HO steam engine!
This is how they added sound to the mainstream HO scale model railroads back in the 1970s. It is a boxcar with some kind of pellets inside that move to the rhythm of the train. so it gives the illusion of the chug chug from the train. Pretty neat. It is totally manual--not electronic.
And a classic looking boxcar to boot!
CONDITION: C-7. Looks good. Complete. There are some rubs on the roof. Chug chug works fine. With nice box.