Ancient rusting signal bridge, spanning South San Francisco yard, holding modern signals that are still in use. It’s a strange artifact, given Caltrain’s recent aggressive signal modernization program. I’m sure there’s a backstory…

Shot with the Nikon D70s and the 18-70mm f/3.5-4.5 zoom at 44mm, ISO 400, f/13, shutter 1/320 sec. Exposure, contrast, and levels adjustments in Aperture.