Hi, I had a Märklin tank, which was intended as a flat car load. When I ran into a picture of an N scale D&RGW X-2915 water car, I decided to build such a water car look alike in Z. See the real X-2915 at next link: http://gelwood.railfan.net/drgw/drgw-x2915acs.jpg
Very good. I was looking at the prototype photo and it sure looked like a black tank painted white that was fading away. Did different colors of tank cars go with different content?
Yes, depending on the road. Black for fuel oil, white/stainless for drinking/showers, red for fires, etc. On some roads may be 1 car with that color in the MOW/company service fleet. Get a copy of the Morning Sun Freight Car in Color book on your road. Find the MOW/company service section.