For a long time I have been wanting to try my hand at building these tank cars that were purchased by the Chicago Great Western. Morning Sun Books has a great section in their color guide book by Gene Green on this equipment. Besides the color coding the CGW utilized for the type of material transported:
Maroon for Diesel
Silver for Kerosene
Black for Oil
Green for Lube Oil
There were subtle differences in these cars as they were delivered over several purchase orders from the manufacturers. These were the modern day predecessors to tank cars we see on the rails today.
So I am in my early research phase to learn more about these tank cars in order to faithfully reproduce them for my CGW layout and rolling stock collection. If anyone knows of builders plans please let me know where I can find this as reference information. Thanks!