>This signal installation was the only AC track-circuit system in the vicinity of San Francisco (at the time) which used light signals.

The installation on the NWP doesn't count??

In this day and age, the FRA will permit no distant signals nor AC line wires, for very good reasons. There are also concerns with required periodic apparatus testing, record keeping, and WRM's willingness to enforce the signal indications (i.e. to avoid another Chatsworth-like incident), not to mention the additional liability involved. There is, BTW, almost enough apparatus to signal the entire current operation under wire -- the only thing lacking are sufficient impedance bonds. Except for two pieces of test apparatus, WRM has no code transmitters.