Hi Steve,
It’s a one of a kind Rube Goldberg item. Actually built around the blower (a 12 volt bilge blower) I got the speed regulator in Hong Kong for $18 so that I wouldn’t blow the ballast away, and it is working very well. I had the freight car bottom from when I converted to the lowered car bottoms. I made the tube at the end of the blower out of card stock and TAP Plastics ABS plastic, it is wrapped with good old duct tape. I need to dress it up a bit so that the spst switch and the potentiometer look neater. I also added a 4 amp fuse in the circuit. If I allow the speed to go full, it will move my ballast. The car is quite heavy, so I also have ball bearing wheel sets. The little Kalamazoo Donkey had no problem pushing it around the layout. With my brief trials, I think that I will make the next outlet tube out of flexible plastic, as it will hold up better in wet weather, and I would make the end of the tub wider (this will be a winter project). I use it in conjunction with Bill’s RailSweeper.