I made some coal loads for some Lionel hoopers for my C & O coal train a couple years back. It’s pretty easy. Cut some 1” insulation foam to fit inside the hooper used a rasp to shape the top of foam to look like a rippled load of coal. Painted the loads black then spread Elmers white glue on the top and sprinkled fine coal in the glued area. The coal is used as a blasting media. I bought it at TSC near me. At the time the blasting media was about $8.00 for a 25 lb bag.
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