Here's a picture of my latest wagon, fresh out of the paint shop, though that's not the case with the prototype. Painting is with artist's acrylics, over an undercoat of Tamiya fine grey primer. The wagon is an association chassis and plastic body kit. For some reason I decided to use the kit I had, which didn't have top doors, and add them myself from scraps of styrene. The repairs to the side panels were also from styrene sheet.
So now I have three mineral wagons:
I'm not quite sure whether this wagon should have a darker chassis, or the earlier two should be lighter, or both? I did work from a specific photo for this latest wagon, so it should be more accurate.