The little narrow gauge railroad, The Uintah Railway, had built 7 rectangular steel water cars. (I have a G-gauge Uintah #021 water car for my #50 Mallet pulled gilsonite train.)
By 1939 six of these up for sale, 017-021 and 023. In May 1940 D&RGW bought all six to run on their narrow gauge, renumbering them 0465 thru 0470.