Google is our friend. It took a couple of steps, but that's an LOC FSA pic from WWII that you can find here:
The 19 Mb TIFF version has a LOT more detail!
I defer to Steve Hile, but UTLX 19656 seems to be a bit of an oddball. Steve's 1938 roster indicates these were early 6500-gal X-3 cars, that received new 8000-gal tanks ca. 1930. Note the tank has four longitudinal courses, which none of the "conventional" X-3s had. This might explain the rather curious 1918 build date.
The two cars in front of 19656 both look like UTLX Class X (or XX) cars, 6500 gallons.
Great photo that I had not seen before; thanks for posting Bob.
Swall Meadows, CA