Over the years I've picked up several old "trainset quality" tank cars that have features or appearance noticably different from the Athearn single-dome tank car that you see _way_ too many of on most layouts. My goal was, and still is, to turn them into MofW tank cars for mine or friends' layouts, which are all post-1960 so that's outside the scope of this list. However, one of my finds was a silver Mobilgas ICC-103 8,000g tank of unknown manufacturer, although this shot of a more recent Mantua offering seems to be from the same mold:
When was the silver Mobilgas scheme in use? The large Mobilgas black and the horses flanking it are red of course. Since I've loaned my Culotta steam-era tank car book to a friend, I can't look through it for any likely candidates. There aren't any in Kincaid's recent Tank Car Color Guide.