VTA broke ground this summer on the $12. 7 billion project, which involves a 5-mile long, 54-foot diameter single tunnel to be bored nearly 100 feet under downtown San Jose. . The Santa Clara Valley Transportation Authority (VTA) has selected Bechtel Infrastructure Corporation to provide construction management services for the Bay Area Rapid Transit's (BART) Silicon Valley Phase II extension, a project which will connect North San Jose and Santa Clara residents with the. . The Clear Choice for the Future of BART Silicon Valley, A Smarter Design for Faster, Cost-Effective Transit A single-bore tunnel is the smarter, faster, and more community-friendly way to complete the final phase of VTA's BART (Bay Area Rapid Transit) Silicon Valley Extension, according to a new. . A massive cutter soil-mixing rig injects materials into soil at the West Portal construction site in San José on June 23, 2025. Some engineering experts raised questions about projected costs and construction timelines in a new VTA report about the long-awaited plans to connect more of the South. . As the Santa Clara Valley Transportation Authority tries to cobble together $1. 2 billion in cost savings for the final leg of the San Jose BART extension, transit officials are recommending they ditch the tunnel contractor that's been on the payroll for the last three years. Tom Maguire, the. . (UI) — The Santa Clara Valley Transportation Authority (VTA) has confirmed the large single-bore configuration as the preferred tunnel design for the BART Silicon Valley Phase II project, following an independent peer review by tunneling and transit experts from agencies across the country. During. . VTA's BART Silicon Valley Phase II Extension Project includes an approximately five-mile long tunnel. Tunnel construction is anticipated to begin south of the Santa Clara Station near Newhall Yard, running below the Caltrain tracks and underneath I-880. From there, the tunnel continues southeast. .
