• Dumbarton Rail

    Functioning as a connector to the current Caltrain system, standard rail across a rebuilt Dumbarton Rail Bridge would serve the increasing cross-bay travel market. It will connect riders in Fremont, Newark, Union City, and other east bay cities served by BART, ACE and the Capitol Corridor, to Caltrain on the peninsula.

    BayRail Alliance supports the Dumbarton Rail project. It will speed travel from the east bay to the peninsula, and reduce the delays and conflicts that ACE and Amtrak trains currently experience with freight traffic. During rush hour, automobile traffic approaching the parallel Dumbarton automobile bridge is heavily congested, slowing the Dumbarton Express bus and making the bus a less attractive public transit option during peak commute times.

    Corridor map

    The rail bridge, located just south of where Highway 84 crosses the Bay, was in use until the 1980’s. When riding Caltrain, you can see the north- and south-bound wyes from the Dumbarton line connecting to the Caltrain tracks south of the Redwood City Caltrain station, just south of Woodside Road. You can also see the remains of the Dumbarton rail trestle to the south while crossing the Dumbarton auto bridge.


    The project involves repairing and upgrading damaged rail bridges and tracks spanning the bay between Redwood City and Newark; improving existing tracks and signal controls; constructing three new passenger rail stations in Menlo Park/East Palo Alto, Newark, Union City, and a new layover facility in the East Bay; and upgrading the Fremont Centerville station.

    Total corridor length is 20.5 miles, much of which has been in active use for a century. Only a relatively short 5-mile segment has been out of service since the mid-1980s. The Dumbarton rail bridge itself is 310 feet long and the Newark Slough bridge is 188 feet long.

    Initial service is proposed to consist of six trains across the bridge during the morning commute and six during the evening commute. Morning trains will originate at the Union City Intermodal Station, cross the bay, and then three trains will travel north to San Francisco and three will travel south to San Jose along the Caltrain line. In the evening, all trains will reverse pattern and travel back to Union City.

    Other service patterns and frequency would be possible in the future as the service gains in popularity.


    Decisions for the Dumbarton Rail project are made by the 13-member Dumbarton Policy Advisory Committee. The operations of this committee are funded by the following government agencies, which have a specified number of representatives to the Committee.

    • Metropolitan Transportation Commission (MTC), 3 reps
    • San Mateo County Transportation Authority (SMCTA), 3 reps
    • Santa Clara Valley Transportation Authority (VTA), 3 reps
    • Alameda County Transportation Improvement Authority (ACTIA), 3 reps
    • Capitol Corridor Joint Powers Authority (CCJPA), 1 rep

    » List of current representatives

    There is also a Project Technical Advisory Committee consisting of staff members from various entities within the project area. Caltrain’s governing agency (PCJPB) is the lead agency for the Dumbarton Rail project, in charge of design, construction, and operation.


    The Dumbarton Rail Bridge was built in 1910 by a “paper subsidiary” of Southern Pacific, and was the first bridge to be built across San Francisco Bay.

    The line primarily carried freight trains, but from 1912 to at least 1918, it was used to provide a transbay passenger service. Both mixed trains (combined freight-passenger) trains and all- passenger trains traversed the bridge.  Parts of the line approaching the bridge are still used today for rail freight.

    » View historic Dumbarton passenger timetables on Centerville Depot website

    In early 2000 a bill sponsored by State Senators Jackie Speier (D-San Mateo) and Byron Sher (D-Palo Alto), included funding for Dumbarton commuter rail from the Stockton-Pleasanton ACE route. The bill’s sponsors suggested that these trains could be running as early as 2003. This legislative action led to the establishment of Caltrain’s “Baby Bullet” service in 2004. However, funding for Dumbarton rail was removed from the bill before the bill was approved by the Transportation Committee.

    Perhaps the staunchest advocate of the project for many years has been Jim Bigelow, the nicknamed “Father of Dumbarton Rail”, who is active in various chambers of commerce in San Mateo County. He won an MTC Award of Merit for his work in 2004.

    Current status

    Environmental evaluation is suspended at this point as MTC diverted funding to other projects such as BART extension to Warm Springs, which BayRail is strongly against. Even though this project is regional in nature and will provide benefits to multiple counties, this project lacks strong political stakeholders for the same reason.

    This project is technically complex because it involves usage of UP owned tracks in the East Bay and Caltrain tracks on the Peninsula. Particularly on the Peninsula, under a “commuter rail” scenario, DRC trains would inter-operate with electric Caltrain and eventually high speed trains. The “rail shuttle alternative” would not involve inter-operation on the Peninsula but would require transfer at Redwood City.

    The City of Menlo Park is proposing a West Bay only project that would reactivate rail from the Caltrain main line to the Facebook Area.


    Green Caltrain updates on Dumbarton Rail