1 vote

SP - Dumbarton Bridge


Dumbarton RR Swing Bridge

Looking SW

Photo taken by Craig Philpott in July 2010


BH Photo #169904

Street View 


This bridge was the first bridge to cross San Francisco Bay. It cost 1,500,000 dollars to build (equivalent to $38,000,000 today). It was dedicated on September 24th, 1910. The truss spans were fabricated in Oakland and hauled to site by the ferry "Thoroughfare". In 1982 it was welded in the open position and part of the Palo Alto side was removed; it is currently (2018) abandoned in place.

source "California Drawbridges" Bernard C. Winn


Efforts to return the old Southern Pacific Dumbarton rail bridge crossing the southern part of San Francisco Bay to service have taken a major step forward, with a recent negotiating agreement allowing social media giant Facebook to work with an Australian infrastructure investment firm to revitalize that long-dormant rail corridor.

On May 6, Facebook entered into an negotiations with the San Mateo County Transit District to improve the Dumbarton corridor, a 14-mile ex-SP line connecting Union City in the East Bay and Redwood City on the peninsula. That could enable a rail connection with the Altamont Commuter Express — whose Fremont station is about two miles east of the east end of the still-moribund Dumbarton corridor — and with Caltrain in Redwood City.

It hasn’t been established which agency would operate trains over the span, should the rehabilitation occur. Past studies, the oldest dating from the 1990s, have considered shuttle service between Union City or Fremont and Redwood City, as well as “extended” service that included Union City-San Francisco and Union City-San Jose trains.

The rail bridge, opened in 1910, carried SP freight trains between the old Bayshore Yard south of San Francisco and points east, including Sacramento and the San Joaquin Valley. Some passenger trains, including the San Joaquin Daylight, also used it. The last freight train ran over the bridge in 1982, and the bridge has been owned by the transit district since 1994.

[More in article at link.]


Abandoned baltimore through truss bridge over San Francisco Bay on Caltrain
Newark, Alameda County, California, and San Mateo County, California
Future prospects
Owned by San Mateo County Transit District; proposed for rebuilding for commuter rail operation, with possible financial contributions from Facebook, Inc.
Built 1910, last used for freight 1982; acquired by San Mateo County Transit District 1994
- William Hood
- San Mateo County Transit District
- Southern Pacific Railroad (SP)
Baltimore through truss swing bridge with three spans of Pratt through truss approach span on each end and extensive deck trestle approaches.
Length of largest span: 316.0 ft.
Total length: 7,528.0 ft. (1.4 mi.)
Deck width: 27.0 ft.
Approximate latitude, longitude
+37.49729, -122.11006   (decimal degrees)
37°29'50" N, 122°06'36" W   (degrees°minutes'seconds")
Approximate UTM coordinates
10/578665/4150412 (zone/easting/northing)
Quadrangle map:
Mountain View
11 ft. above sea level
Inventory number
BH 45455 (Bridgehunter.com ID)

Update Log 

  • June 18, 2018: Updated by Alexander D. Mitchell IV: Proposal to rebuild bridge for transit operation linked
  • May 18, 2018: Updated by Leslie R trick: Added info to description
  • January 20, 2017: New photos from Dave King
  • April 16, 2015: New photos from Zachary S
  • October 14, 2013: Updated by Luke Harden: Bridge definitely doomed
  • July 18, 2010: Updated by Craig Philpott: refined design and added photos
  • June 6, 2010: New Street View added by Cliff Darby
  • June 5, 2010: Added by Craig Philpott



SP - Dumbarton Bridge
Posted February 17, 2020, by Gordon Osmundson (gophoto [at] sbcglobal [dot] net)

The San Joaquin Daylight did not operate over this bridge, nor did any other regularly scheduled passenger train.

SP Dumbarton Bridge Video Footage
Posted February 18, 2014, by Cat Cook (sales [at] theshortline [dot] com)

I have a customer who is looking for any video footage of Southern Pacific traveling on this bridge. Anyone have any ideas?



The Short Line



Dumbarton Railroad Bridge
Posted June 5, 2010, by Craig Philpott (cphilpott [at] puc [dot] edu)

Bing.com has excellent views of this bridge in birds eye view.