Way back in 2004 when the San Francisco peninsular commuter rail service known as Caltrain was being modernized with new trains, new passing tracks and new signaling, only a few pieces of Southern Pacific era hardware was retained. Perhaps the most spectacular of these was the 8 track signal bridge just north of the South San Francisco Station sources claim dates from 1907.
Needed to span a number of freight sidings, the signal bridge was evidently found to be in reasonable condition and subsequently fitted with two pairs of modern signals. Unfortunately, 15 years later freight service on the peninsula has continued to shrink and a new electrification project has provided capitol money to re-build the South San Francisco holdout platfom and replace the century old lattice steel signal bridge with a modern cantilever.
While the Bay Area's preservation mindset makes its likely that the signal bridge will avoid being sent to a scrap yard, the electrification project also makes it likely that the signal bridge will need to be moved elsewhere, perhaps to an existing museum, a Caltrain parking lot as an art installation or maybe just the purgatory of the former SP Bayshore shop and yard complex while the powers that be figure out what to do.