Update Feb 2021: See additional new images of the Sunnyside Powerhouse, including the engine rooms
Sunnyside played an important role in the development of the first electric streetcar in San Francisco. The pioneering enterprise was initiated in 1890 by streetcar-railway engineer John Wesley Hartzell, with financial backing from millionaire real-estate speculator Behrend Joost. Before that, horse-powered and cable-driven streetcars were the norm in the city. Soon the newly introduced technology would power many of San Francisco’s many privately-held transit lines.
But the San Francisco and San Mateo Railway was the first electric railroad in the city, and central to the project, producing the electric energy to run the line, was the Sunnyside Powerhouse, located on the flatiron-shaped block at the eastern end of Monterey Boulevard, then called Sunnyside Avenue.