Caltrain tunnel #2, just north of Cesar Chavez Blvd in San Francisco, is unique among the four San Francisco tunnels in having two bores, only one of which contains trackage. In my investigations, I haven’t yet learned whether the second bore contained tracks once upon a time, or if it is just one of those vestigial remnants of grand plans that never came to fruition.

The second bore is walled off at both ends, but that doesn’t seem to have prevented certain types of visitors from entering. I wonder what’s in there?

Shot with the Nikon D70s and the 18-70mm f/3.5-4.5 zoom at 70mm, ISO 400, f/4.5, shutter 1/160 sec. Contrast and levels adjustments in Aperture.