The Golden State, California, by far the largest U.S. State in population is a region into itself. It is also a place that fully embraced the car and is now trying to get out of that mindset. After the last Pacific Electric Red Car Streetcar ran in Los Angeles (that previously had the largest street railway network in the world in the 1920s) in 1961, there were just two rail services left in the Golden State. What is today Caltrain, then known as the Southern Pacific Commute Service has run continuously since railroad service began between San Jose and San Francisco in 1863. In the city of San Francisco there has been continuous streetcar service through the Sunset and Twin Peak tunnels, although trains ran on the surface down Market Street until morphing into the MUNI Metro with Light Rail Cars underground above BART, plus it's iconic cable cars. In May 1971 as Amtrak was created, intercity rail service was also poor, with the four long-distance routes that run to this day (albeit a few under slighlty different names), plus just three daily San Diegan round-trips from Los Angeles to San Diego.
Since BART, an expensive heavy rail-based regional rail system's first segment opened in 1972, the Golden State (as of June 2016) has built over 300 (granted many are small surface light rail stops) new subway, commuter rail and light rail stations. Also requiring crucial mention is the opening of the San Diego Trolley in 1981 that ushered in the current modern lower budget, designed for lower ridership, Light Rail networks that have been built throughout the country. Los Angeles didn't have rail service restored until the opening of the Blue Line in 1990, with San Jose's and Sacramento's opening before this. The L.A. Metro Red Line Subway that opened in 1993 is newest heavy rail system to be built in the continuous United States (San Juan, Puerto Rico opened a subway in 2004).
Historical Timeline of the openings (the first segments) of the still operating rail lines in California:
Please Note: The MUNI Metro, and Sacramento Regional Transit photographs are fully taken but are buried deep in the archive and sections for these lines still need to be made. They will be done at some point in time.