The San Francisco Area Key System was an old public transportation system in the Bay Area for commuters. What a shame that it was seemingly dismantled by automobile manufacturers. There’s even a site that memorializes The Bay Area’s Lost Streetcars.
Tracks, Tires, & Wires catalogues the old transportation system, but I can’t find any copies to read.
The Caltrain HSR Compatibility blog wrote an article in May 2020 about how much the Southern Pacific Railroad Commuter System paid its staff.