Mike to answer your request.
Track cleaning cars: Post war cabooses are good because of their short wheelbase, but almost any old car will work. My preference is a RailKing MTH depressed flat car with a (transformer load to hide added ballast weight) because a very thin spacer is all that's needed between the bottom of the car and the track.
Ballast weight: Lead fishing weights work or anything heavy that fits in the car.
Materials: Spacing material (sponge, wood, styrofoam etc.), Velcro tape (hook side), Scotch Bright scrub pads. Beer, Ale or your favorite adult beverage.
Assembly:
1) Place car on track. Measure the Distance from the bottom of your car to the track.
2) Spacer thickness = Distance - (thickness of Velcro HOOK tape + Scotch Bright thickness).
3) Attach spacer material to bottom of car (Glue or fastening method of your choice). Then stick Velcro HOOK tape to the spacer. Next attach Scotch Bright to Velcro HOOK tape.
4) Place on tracks and add required weights to keep car on track.
5) Test run and enjoy adult beverage.
I permanently have one of these cars in the consist behind the locomotive or have a track cleaning consist parked on a siding that I run once a week. Occasionally I remove the cars from the track to clean the Scotch Bright. Once a year I use some denatured alcohol or track cleaner manually to clean track.
NOTE: I copied this design from a friend when I bought one of his cars.
