OK, Joe Black, I think, is the manufacturer or a track cleaning device that suspends on the rails, between a simple metal framework, an LGB cleaning block. The frame work is a rectangle and has four metal wheels and couplers. The block drags on the rails for cleaning as pushed or pulled by a loco.
Likely, it sold well and you may have one.
If not, I don’t know if it is still being sold.
You may and I’d appreciate your affirmation.
Here’s the tip:
Remove the block from the frame, open it up by squeezing the sides, cut to fit a 150 drit dry-wall sanding “screen” – or less grit if you wish – and install it on the block. Now, add some weight placing it inside the block, close the block and install in the frame. Try it out. Yes, it is more aggressive than the LGB rubberized block. However, IF you have not run trains in some time, this works!
Wendell