Silicon Valley BART Extension construction remains on time, budget

SAN JOSE, Calif. (KGO) -- Phase two of the BART Silicon Valley project is continuing in San Jose.

It will feature six miles of new rail, four stations, as well as residential and retail development.

It's the largest public works project ever undertaken in Santa Clara County.

The shadow of PayPal Park, the construction will connect public transportation in Santa Clara County to the rest of the Bay Area.

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Valley Transportation Authority Chief Megaprojects Delivery Officer Tom Maguire says the project is not only on time, but remains on budget.

"Our cost estimate remains at $12.1-12.5 billion," Maguire said. "Every day or every month that we're delayed, we estimate that every month is worth about $20-30 million. The most important thing we can do to keep ourselves on budget is to stay on schedule."

Starting with the single-bore tunnel that will house the trains, stations and infrastructure needed for this project.

The five-mile dig starts at the West Portal, runs through downtown San Jose and all the way to Berryessa.

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It will be dug by a specialized machine made specifically for this project.

"The machine is a specialized piece of equipment that has a steel shield, so it looks like a sideways steel can," Construction Director Sarah Wilson said.

Wilson adds more than 90% of the walls needed to begin tunneling are completed - still on pace for a 2028 start.

"To date, we've poured more than 45,000 cubic yards of concrete to form these walls. That's around 4,500 concrete trucks," Wilson said.

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Once the tunneling and project is complete, VTA estimates 45 million square feet of housing, retail and commercial development will come along with the transportation.

Santa Clara City Councilmember Suds Jain says it will be transformative for his city and beyond.

"We've been talking about this project for more than 10 years now," Jain said. "To see machines in the ground, we can see that we're going to get this project."

The project remains on schedule to begin welcoming riders in 2037.