BART Warm Springs Extension project is a 5.4 mile (8.69km) extension of the existing Fremont line to the under-construction Warm Springs / South Fremont station. Image courtesy of Ikluft.
BART Warm Springs Extension runs parallel to portions of the Union Pacific Railroad freight corridor. Image courtesy of Pedro Xing.
Construction of Warm Springs / South Fremont station is expected to be completed in 2015. Image courtesy of NapoliRoma.

BART Warm Springs

San Francisco Bay Area Rapid Transit (BART) system is being extended by 5.4 miles (8.69km) from the existing Fremont Station south to a new station called Warm Springs / South Fremont station in the Warm Springs District in Fremont, California, US.

US Federal Transit Administration (FTA) granted a record of decision for the BART Warm Springs extension project in October 2006. The project was proposed to be constructed through two contracts, namely the Fremont Central Park Subway Contract and the Line, Track, Station and Systems Contract (LTTS).

Construction under the Fremont Central Park Subway Contract began in September 2009 and was completed in April 2013. Construction activities under the LTTS contract began in October 2011 and are anticipated to be completed in 2015.

Once operational, the $890m extension project is expected to increase the transit ridership by 4,700 daily trips.

BART Warm Springs Extension track alignment

The Warm Springs Extension alignment runs parallel to portions of the Union Pacific (UP) freight railroad corridor, in addition to Interstates 680 and 880 in southern Alameda County.

"Once operational, the $890m extension project is expected to increase the transit ridership by 4,700 daily trips."

The initial segment of the extension line begins on an embankment at the south end of the existing elevated Fremont BART Station and then crosses over Walnut Avenue on a new overpass structure before descending into a cut-and-cover subway just north of Stevenson Boulevard. The subway track runs beneath the Fremont Central Park before emerging on to surface on the east edge of the park.

The line then passes over Paseo Padre Parkway on an overpass structure and runs southward at-grade, passing under a grade-separated Washington Boulevard. The track finally runs into the Warm Springs/South Fremont Station on a new overpass structure over South Grimmer Boulevard.

Warm Springs / South Fremont station details

The Warm Springs / South Fremont station under construction in the Warm Springs District of Fremont will comprise an at-grade island platform and an overhead concourse.

The station is expected to provide parking space for approximately 2,000 vehicles and create an intermodal access to Valley Transit Authority (VTA), Alameda-Contra Costa Transit (AC Transit) buses, as well as taxi and ‘kiss and ride’ passenger drop-off areas.

The extension project also includes an option to build a station at Irvington between Fremont and Warm Springs / South Fremont stations, which is expected to have a daily ridership to 9,100 trips by 2025.

Construction of California’s Warm Springs Extension project

Works under the Fremont Central Park subway construction contract included the construction of a mile-long subway beneath Fremont Central Park, the trackway embankment, two ventilation structures and the relocation of several recreational amenities within Fremont Central Park.

Various existing structures along Warm Springs Court were also removed or modified under a separate contract awarded in October 2011, in preparation for the construction of the BART track way south of the Warm Springs / South Fremont Station.



Bay Area Rapid Transit (BART) Silicon Valley is a planned 16-mile extension to San Jose, Milpitas and Santa Clara, California.


Works under the LTSS design-build contract include the construction of the trackway, tie-in at the Fremont Station, the new Warm Springs/South Fremont Station and a parking lot.

Funding for Warm Springs Extension project

Major funding for the BART Warm Springs extension project includes $215m contribution from the Alameda County Transportation Improvement Authority (ACTIA), $294m from Metropolitan Transportation Commission (MTC) Regional Measure 1 and 2 Bridge Tolls, $169m from the State of California, $92m from MTC Proposition 1B State & Local Partnership Program (SLPP), and $54m San Francisco International Airport (SFO) Extension Surplus Revenue.

Contractors involved with BART Warm Springs Extension project

The joint venture of Shimmick and Skanska was awarded a $136m contract for the construction of the Fremont Central Park Subway in May 2009.

The LTSS design-build and construction contract for the extension project was awarded in 2011 to Warm Springs Constructors, a joint venture of Kiewit Corporation and Mass. Electric Construction (MEC).

Parsons Brinckerhoff acted as BART’s General Engineering Consultant for the extension project. The conceptual and preliminary design for the new Warm Springs / South Fremont station was provided by San Francisco-based Robin Chiang & Company, which was engaged as the architectural sub-consultant for Parsons Brinckerhoff.

The detailed design for the station is provided by HNTB, the architect for the Warm Springs Constructors design-build team. Parikh Consultants was engaged as the geotechnical engineering consultant for the execution of the LTTS contract.

Livermore-based Parc Services were engaged in October 2011 for the demolition of structures along the Warm Springs Court for the construction of the tail tracks of BART Warm Springs Extension.