Downtown San Jose is getting BART, but you'll have to be patient — the Valley Transportation Authority service is now pushing back its ETA to around 2030, as first reported by the Mercury News.

In this second phase of VTA's BART Silicon Valley project (the first was Berryessa and Milpitas stations, which are scheduled to open by the end of 2019), four more new stations will be added: Alum Rock/28th Street Station, Downtown San José Station, Diridon Station and Santa Clara Station.

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Back in 2014, the timetable for Phase II predicted that downtown San Jose commuters would be riding BART by 2026.

"The 2026 projection was based on environmental clearance and other milestones occurring at specific times," said Bernice Alaniz, BART Silicon Valley business operations and communications director. But there were delays, as is to be expected with a highly conceptual project like this.

Initially, environmental clearance was anticipated for 2017, with engineering and pre-construction happening in 2018. However, environmental clearance got pushed to 2018, and then VTA spent all of 2018 and half of 2019 creating a tunnel design that BART would approve of.

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Fortunately, the single-bore tunnel option that VTA spent the last year or two settling on should be worth it — it will allow them to construct the tunnel without any construction disruption at the surface.

"Rather than doing cut-and-cover and tearing up major runways, which impacts commuters and businesses, this will be done off-street," explained Alaniz. Therefore, the tunnel, trackways and boarding platforms will all be constructed below ground, while the ticketing hall facilities are constructed off-street.

For now, the new estimate for completion is 2029 or 2030, but Alaniz emphasized that this could change.

"It's a projection based on a very conceptual level of design," she explained. "We won't really be able to definitively declare a new schedule until we're past 10 percent and 30 percent complete."

Currently, she says the design endeavor is roughly 2 percent complete. However, future changes in the schedules could mean moving it along earlier, rather than just delaying it more.

"Now as we further in design, there may be some efficiency gains," Alaniz added.

Madeline Wells is an SFGate editorial assistant. Email: madeline.wells@sfgate.com | Twitter: @madwells22