Mike,
I've been suspecting that this photo at Grant was taken by DWB photographers on the special train of January, 1929, likely on the return trip.
Consider:
Scanned from Colorado Rail Annual #12.
Engine 9 and the eastbound DWB special wait at the west end of Webster siding. An east bound freight slowly eases down the Kenosha grade into Hall's Valley.
I believe the train descending into Hall's Valley may be the same one at Grant, with C&S 73 as the locomotive. It's hard in the silhouetted train to identify a tank car though.
After arriving at Webster to take water, the freight would have likely followed the DWB special to Grant, and it's photo was taken there, by the garage and gas station.
At least the date 1929 matches, can't prove much else.
So maybe the Grant photo that you covet resides with other Denver Water Board photos . . .
Jim Courtney
Poulsbo, WA