Garth Groff and Sally Sanford
This SL-SF tank car used to sit in Denver just short of the Union Station. I think it was being used as a stationary fuel tank, or perhaps for waste oil, as I saw it many times from the California Zephyr in the 1990s.
As I was cleaning up this really bad image (shot through an Amtrak coach window), I realized that this is remarkably similar to the old Red Caboose/Intermountain welded tank car. There aren't many verified matches for this model, U.S. Army/DODX, UTLX and a few AC&F leasers with tank platforms.
Garth Groff 🦆