[2] Prior to the completion of the Dumbarton Cut-off, transcontinental rail freight was offloaded at Oakland and ferried to San Francisco.

[6] Preliminary work started in 1904 with the condemnation of land at Dumbarton Point,[7] and the incorporation of the Central California Railway Company, created by several Southern Pacific officers for the sole purpose of building a rail line from Newark to San Mateo.

[10] Henry Rengstorff argued the bridge would impede water traffic, which was needed as an alternate route in case of a railroad strike or natural disaster, such as the recent earthquake.

[18] The bridge was initially anticipated to be completed in mid-1907,[19] then March 1909,[6] but it was not completed and opened until June 1910, providing San Francisco with a more direct transcontinental rail link for freight and passenger service, avoiding detours through Santa Clara and San Jose.

[21] Freight service started on September 12, 1910,[22] and the first passenger train crossed the Dumbarton Cut-off on September 25, 1910, although that was a special-event train, as Southern Pacific, the owner of the Cut-off, intended to limit traffic to freight service.

The increased freight service afforded by the Dumbarton Cut-off caused some Hillsborough residents to complain about the black smoke.

[21] Just before 7 pm on the night of 3 January 1998, the western trestle approach caught on fire,[28] and the smoke from the creosote-treated timbers forced the shutdown of the Dumbarton (road) Bridge in both directions.

[32] The proposed Dumbarton Rail Corridor service would provide six westbound trains originating from a rebuilt Union City intermodal station; after crossing the rebuilt Dumbarton Cut-off bridges, three trains would proceed north to San Francisco and three trains would proceed south to San Jose, making limited stop service at the existing Caltrain stations.

From Union City, trains would stop at stations in Fremont (Fremont Centerville Station), Newark and Menlo Park/East Palo Alto before joining the main Caltrain line at Redwood City (northbound) or Menlo Park (southbound).

Although the Dumbarton Rail Corridor was almost fully funded in 2001 (the Metropolitan Transportation Commission estimated the total capital cost for the Dumbarton Rail Corridor was US$129,000,000 (equivalent to $222,000,000 in 2023); of that, 91% had been secured or was pending via local sales taxes in San Mateo, Alameda, and Santa Clara Counties),[35] subsequent studies, including the 2003 Dumbarton Rail Corridor Project Study Report,[36] identified several deficiencies in the existing infrastructure.

[38] In 2008, US$91,000,000 (equivalent to $128,800,000 in 2023) in RM2 funds were loaned from Dumbarton Rail Corridor to BART for work on the Warm Springs Extension.

[41] On June 2, 2019, a brush fire that authorities suspected was arson spread to the wooden trestle on the eastern approach near the Newark Slough Bridge.

[5][14] The six truss spans were constructed on shore and floated into place using a converted freight car boat, the Thoroughfare.

[5][23] When the swing span is open to accommodate water traffic, it affords a 125-foot (38 m) wide navigation channel to either side.

The swing span's center is supported by a 40-foot (12 m) diameter cylindrical concrete pier resting atop more than one hundred piles.

On 21 August 1907, the supports for a 120-foot (37 m) section of eastern approach trestle, which had been built to within 120 feet (37 m) of the swing span, washed out in the receding tide and the bridge plans were modified.