Top image: Berryessa/North San José BART station on opening day. Photo: Troy / CC BY-SA 4.0 via Wikimedia Commons

For years, BART’s extension through downtown San Jose existed mostly as renderings and cost estimates. This fall it became a very large hole in the ground.

In early September, crews at the Newhall Yard site near Interstate 880 finished 100% of the excavation for the West Portal launch structure, the pit from which a tunnel boring machine will begin drilling the project’s five-mile tunnel, according to the Santa Clara Valley Transportation Authority’s fall project newsletter. The excavation reached a maximum depth of 83.5 feet and removed some 200,000 cubic yards of material. Crews are now pouring the heavy reinforced slab that must bear the machine’s weight before it drills a 53-foot-diameter bore. VTA’s October construction update says work at the site runs 24 hours a day, Monday through Saturday, and that the machine is expected to arrive “later next year.”

A target price, not a fixed one

The more consequential milestone is contractual. In August, VTA and its tunnel contractor, Kiewit Shea Traylor, executed an Amended and Restated Agreement for Contract Package 2, which covers the tunnel scope. According to VTA’s Aug. 12 announcement, the agreement consolidates the contract into a single document and “locks in a target price while keeping this critical work moving in a challenging heavy construction market.” The fall newsletter adds that both parties committed to identifying cost-saving opportunities, and that with the agreement in place the next year of pre-tunneling construction is authorized.

VTA describes the result as “great cost certainty.” A target price is a different instrument from a hard fixed price, however, and the public documents released so far emphasize the target rather than detailing how overruns or savings would be shared. For a project of this scale and duration, the terms of that sharing will determine how much risk taxpayers carry over the next decade. The VTA Board and the project’s oversight committee, which meet again Nov. 5 and Nov. 12, are the venues where those details should surface.

Regional money arrives

The project also landed money. The Metropolitan Transportation Commission approved an initial $192.5 million allocation, the first tranche of a $375 million grant from Regional Measure 3, the bridge-toll measure voters approved in 2018. VTA says the funds will pay for work required before tunneling, such as installing instruments that monitor ground conditions.

“Now is not the time to take our foot off the pedal,” state Sen. Dave Cortese, a former MTC chair, said in a statement quoted by VTA. “We must continue securing the funding and support needed to keep construction moving, protect this investment, and get BART to Downtown San José and Santa Clara. Our region has waited long enough.”

What is being built

The Phase II extension is a six-mile, four-station line from the Berryessa/North San José station, opened in 2020, through downtown to the city of Santa Clara, according to VTA project materials. Plans call for underground stations at 28th Street/Little Portugal, Downtown San José and Diridon, and a ground-level station in Santa Clara. The project’s construction page targets passenger service by 2037. Geotechnical drilling near Diridon, along The Alameda and Stockton Avenue, is scheduled to begin as early as Oct. 19 for about four weeks.

The long view

Two clocks are running. One is the construction schedule, measured in tunnel-boring months and station excavations. The other is political: voters across five Bay Area counties will decide Nov. 3 on Measure RTM, a regional sales tax meant to keep BART, Caltrain and other systems from deep service cuts. As SPUR, which co-leads the measure’s campaign, has explained, BART service in Santa Clara County is already covered by a separate VTA agreement that addresses operating deficits. Even so, a downtown San Jose BART station arriving in 2037 assumes a healthy regional BART network to connect to.

San Jose has been promised this line, in one form or another, for a generation. The excavated launch pit is the most tangible evidence yet that it is coming. The contract terms and regional finances will determine whether it arrives on time, and at what cost.

Sources: VTA BART Silicon Valley Phase II fall newsletter and October 2026 construction update; VTA blog (Aug. 12, 2026); VTA construction notices and project pages; SPUR (June 18, 2026).