Digging Rock in Daly City

This week, we bring you a little piece of local history that's been long lost to the ages, a throwback to the industrial past of San Francisco. Tucked away on the northwestern tip of San Bruno Mountain, just over the county line into Daly City, was a small but productive facility that fueled the construction of San Francisco's streetcar lines for more than 50 years. Called "Daly's Quarry," this plot of land was the site of a rock mine and processing plant that produced track ballast for the city's expanding rail network.
 

Daly's Quarry View from Hill Above | September 10, 1926 | U10398

From the time when Daly City was nothing but an expanse of farmland and empty plots, workers chipped away at the hillside, breaking off chunks of rock and passing them through a crusher to produce gravel, which was then used to support the ties and rails of streetcar lines. As the slope was removed, the mining tracks and buildings of the quarry had to be shifted deeper into the hill to access more rock. Although we have no records of it in the Archive, the quarry was likely built around 1892 by the San Francisco and San Mateo Electric Railway (SF & SM), San Francisco's first electric streetcar company. After the SF & SM was folded into the private transit company United Railroads of San Francisco (URR) in 1902, the quarry continued to churn out crushed rock until its usefulness began to dwindle around 1939.

In 1944, Muni purchased all of the assets of URR's successor, the Market Street Railway Company, including the land and facilities of the ballast plant. At this time, Muni was transitioning away from rail-based service in favor of bus operations, so the days of the quarry were numbered. Along with many of the aged and ramshackle properties acquired with the purchase of the MSRy, Daly's Quarry was sold by the city to provide revenue for Muni's operation and growth.

Today, the quarry site near the terminus of the 14 and 14R-Mission routes on Mission Street and San Jose Avenue is a far cry from the dusty, noisy operation of years past. The land is now home to a Catholic church and school, just behind the Daly City History Museum.

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