Has any manufacturer ever made an HO scale modern carbon black car? Has there ever been one produced in brass? I really beleive they would sell well. There are in a lot of trains here in northwestern Ohio with them. I realize most of them are painted black. But I know there is a Cabosil car that is green with yellow/gold lettering. But it doesn't carry carbon black. I was told what it carried, but I don't remember right now. Thanks.
I don't know of anyone that makes a modern carbon black car yet. The car you speak of is a silica resin car. Pittsburgh Chemicals has gray cars, DeGussa Chemicals has pretty blue cars. Although I've not seen one, your green cars would be owned by Cabot and probably carry silica resins also. Carbon black and resin cars are made by ACF(now ARI), Pullman Standard, Thrall and some companies have them built in their shops. They are mostly a standard car with extra roof hatches, side sample spigots(not all cars) and round hatch openings on the bottom of the standard compartments. I guess what I'm trying to say is with a few modifications, you could use one of many different centerflow type kits to come close. Paint them black and use some standard reporting marks and you will have some of your own. Try to match some pictures if you can.
Good Luck, Mike