VTA approves tunnel boring machine for $12B downtown San Jose BART extension
SAN JOSE – The Santa Clara Valley Transportation Authority said Monday it authorized the purchase of the transit tunnel boring machine to complete the five-mile underground section of the VTA BART Silicon Valley extension into downtown San Jose and Santa Clara.
The transit authority said in a statement that it ordered the $76 million custom-built tunnel boring machine from Herrenknecht, a company specializing in customized tunneling equipment for projects around the world.
The state-of-the-art boring machine will dig the largest single-bore transit tunnel in the world, nearly 54 feet in diameter. It's capable of digging 30 to 40 feet a day, according to VTA.
"There's no turning back now," said San Jose Mayor and VTA Board Member Matt Mahan, in a statement released Monday. "This purchase cements our commitment to connecting the entire Bay via rail. When complete, BART to Silicon Valley will unlock tremendous transit capacity and economic growth for our region."
The machine will be designed to operate in areas with high water tables, and the geology of sands, gravels, silts, and clays prevalent in the South Bay.
VTA said there were extensive geotechnical investigations through comprehensive boring samples along the route that will connect the downtown San Jose Diridon Station and Santa Clara with the newly opened BART Berryessa station in North San Jose.
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"This is a momentous next step," said Santa Clara County Supervisor and VTA Board Vice Chair Cindy Chavez. "It represents more than just moving dirt—it represents being one step closer to moving people to jobs, to family, and to the entire region. Thousands of jobs will be created during construction, with thousands more fueling this transit-oriented development."
The tunnel boring machine will be designed, manufactured, assembled, and tested by the manufacturer at its German factory and then disassembled for shipping. The pieces will then be shipped to Santa Clara County and reassembled at the project's West Portal/Newhall Yard where the tunnel work will begin in 2025.
The machine is expected to take approximately three to four years to complete the five-mile-long tunnel. The boring machine will eventually be extracted on the east side of US 101 near Las Plumas Avenue in San Jose.
The six-mile BART extension will include four new stations in San Jose and Santa Clara. The cost has been estimated at more than $12 billion.