This water tank is probably a leftover from the days of steam locomotives. It is near a siding and what used to be a wye at Grass Lake, which is 16 miles (25 km) north of the summit of Mt. Shasta.
Grass Lake is a marshy body of water that dries up periodically.
Where is your signature? This is funny to me because I worked with a guy who belonged to a cult--he even used to joke about it being just that. Every year his group made a trek to Mount Shasta.
