Southern Pacific Railroad's corporate headquarters was located at 1 Market Street in San Francisco, California. But for the average San Franciscan, they only knew the SP at Third and Townsend, where the railroad's commuter trains departed for a run down the Peninsula to San Jose. Ready to depart "the City" on a gloomy March 23, 1974, is "commute" train 116, consisting of three "subs" led by SD9E 4450 (ex-SP SD9 3822, originally SP 5363). The 4450 is one of two steam generator-equipped SD9s on the SP, having been built by EMD in April 1954.
Where once there was only one commuter carrier, Southern Pacific between San Jose and San Francisco, today there are three: Caltrain (former SP), Altamont Commuter Express, and the newest, SMART (Sonoma-Marin Rapid Transit).