Judging by the rubber band on the one end, it obviously converted horizontal rotation to vertical rotation. What drove it, and what it was driving is obviously missing … got me beat !!!
There are two “cut outs” directly behind the brackets on each side that line up with the axle that is closest to the middle of the car on each end. Looks like it would convert the horizontal rolling of the axles to the verticle axle which appears to have some sort of cleaning or abrasive pad on it…
Maybe the guts to some kind of operating cattle car. (or milk or mail car?) The spacing of the ties on the track don’t look like standard HO, but I doubt that’s a clue to anything.[%-)] It definitely looks like all the parts aren’t there.
Here is a link to the actual model: http://tycotrain.tripod.com/redboxerafreightcars/id3.html I wonder how well it actually worked? Unlike Lionel, which used a motor for many of its action cars, this relied on the wheelsets for power.