The Sunnyside Powerhouse: New Photographs

Read more about the Sunnyside Powerhouse and the San Francisco and San Mateo Electric Railway.

To add to the recently revealed photo of the Sunnyside Powerhouse, here are five more images from the same album at the San Mateo County Historical Association, including unseen interior shots from the engine room. They were taken by a photographer from the company that supplied the engines, Risdon Iron Works, on the occasion of the opening of the powerhouse and the new electric streetcar line in April 1892.

These new photos are unmatched by any other known ones of Sunnyside’s lost landmark, all of which date to after the powerhouse ceased to operate in 1901. These show a car house and power plant just constructed, ready to revolutionize San Francisco’s urban railways with the introduction of electricity for propulsion. For the first time, the machinery of the powerhouse engine room can be seen.

First, here is the exterior shot I recently posted, showing the frontage on Sunnyside Avenue (now Monterey Blvd), with the distinctive conical corner tower. The big doors to the car house are visible, with car no.15 just peeking out of one. Perhaps from the viewing deck of the tower, General Manager Hartzell or President Joost could survey the cars as they traversed the spur of track into the car house, or just take in the view of the undeveloped land to the south and east–the future site of the city’s expansion in the early twentieth century.

This image, taken looking west, shows a lineup of nine streetcars along Sunnyside Avenue, all looking new and shiny. It was taken in the afternoon, and may be on the day of the big opening ceremonies. (Read an account of the day in this post.)

Unlike the figures in the front shot, most of the people in this one are blurred, except for this fellow. I haven’t identified him yet; his dress suggests he is a VIP at the opening. (Have a suggestion? Email me.)

Here is the condensing pond, a massive cooling apparatus that was about two-thirds the size of an Olympic swimming pool, located on the east side of the powerhouse, between Sunnyside and Circular Avenues. The view is looking east-southeast from the edge of the pond. It would have been an eye-catching site for all streetcar riders as they came through Sunnyside. (See diagram toward end of this post for location.)

Notable in the distance in this photo is the largely developed land that is now Mission Terrace and the hills of Excelsior. Mission Street is the prominent horizontal line about halfway between the top of the workers and the highest hill, which is now McLaren Park. The powerhouse took its water from a well at Santa Rosa and San Jose Avenues, which was piped up. Behind the men a pipe can be seen propped on a trestle, though whether this is part of that water source, I don’t yet know.

The following three images were taken inside the engine room, and show the electrical generation machinery that powered the line.

Using the 1900 Sanborn map which diagramed the plant, I’ve marked the approximate location of the photographer for the three engine room shots. (Do you have a correction? Email me.)

Following the Sanborn diagram, Emiliano Echevveria offers this description of the system:

“The steam is generated in the Elephant boilers in the pink section (the black squares). The steam is piped up to the generating room where the steam is injected into the engines, to which the flywheels (drivers) are directly attached. The flywheels, using rope belts, drive the generators to 600 VDC.  The energy goes out feeder cables to attach at designated locations along the lines to the trolley wire, to insure equal power distribution.  After it leaves the engines, the steam is sucked via tubing to the condensing pond, all the while in piping, to be re-condensed into water and be reused in the boilers, which is water-saving.”

The San Francisco and San Mateo Electric Railway was a pioneering project and changed urban transit in the city forever. The site of the Sunnyside Powerhouse deserves to be given California Landmark status.

---

Read more about the Sunnyside Powerhouse and the San Francisco and San Mateo Electric Railway.

---

My sincerest thanks to Emiliano Echeverria for his expertise; to David Gallagher for the tip; and to Kathleen Laderman for her excellent eye and inexhaustible local history knowledge.