This photo is undoubtedly of Bernal Cut in San Francisco, during 1929-30 widening to accomodate Alemany Boulevard (and autos). The railroad is SP's Colma branch through Daly City, and the bridge over the tracks is Richland Avenue.

A bit of history for "ghost railroad" buffs to put this posting and photo into perspective; trackage shown was originally constructed by San Francisco and San Jose RR (historical predecesor to the SP) during the 1860s. It was a link in the original route for SP's famed Coast Line. Bernal Cut was a 300 foot grade impediment for trains in both directions, and increased rail traffic during 1900s (Harriman era) prompted construction of the Bayshore Cutoff along the eastern shoreline of the SF Peninsula. In 1907, traffic was shifted to the Bayshore Cutoff, this trackage was downgraded to branchline, and subsequently abandoned in pieces over the next few decades.

Here is a link, with historical photos showing Bernal Cut area growth and development;
[www.foundsf.org]

And another link, describing abandonment of the Colma branch;
[www.abandonedrails.com]