In order to advancing the BART Silicon Valley Phase II Project (BSVII), the Santa Clara Valley Transportation Authority (VTA) has ordered a TBM, which has been manufactured by Herrenknecht and with US$76m (£62m) value is due to have a 16.5m diameter, that makes it one of the largest TBMs in the world. Stretching the heavy rail service from Berryessa/North San Jose through Downtown San Jose into Santa Clara, the 8km tunnel will be excavated by this machine.
The purpose of designing this TBM will be operating in areas with higher water tables and the geology of sands, gravel, silts, and clays in the South Bay, whereas its daily performance is slated to be around 9-12m and take three to four years to dig the tunnel.
As the first rail project in the US to be constructed by a single bore, this tunnel will have an inner diameter of 14.6m and house twin tracks and three station platforms.
The VTA’s plan is commissioning a TBM naming contest before the machine arrives in the US.
Also the design-build contract for the tunnel and trackwork was granted to Kiewit Shea Traylor joint venture (KSTJV) in previous year.
