BART directors received an update Thursday on early steps toward a second transbay BART crossing that could include both standard-gauge rail tracks and the wider BART tracks.
That would allow Capitol Corridor riders to have a one-seat ride from Sacramento to San Francisco.
The added train access would augment the existing Transbay Tube and could tie together the "megaregion", connecting the Peninsula, Silicon Valley and San Francisco with the East Bay, Sacramento and Central Valley communities.
The idea is to "create more opportunities for people to ditch the car," said BART Board of Directors President Robert Raburn during Thursday's review of the planning process.
The next stage is to commission a feasibility study to narrow alternatives for the second crossing to a short list of two to four options. After that, the BART board could award a contract for the study in mid-2019.
Construction on what's expected to be a multi-billion dollar crossing wouldn't start for another 10 years, but BART officials said they need to start soon. Although BART plans to increase capacity through the existing Transbay Tube, demand is expected to outpace capacity by 2040 in medium- and high-growth scenarios.
Studies and early engineering for the project will be funded by $150 million from Measure RR, the $3.5 billion BART modernization bond measure approved by voters two years ago. Another $50 million for the study will come from Regional Measure 3, approved last June.
Planners have listed six objectives for the project, including the possibility of 24-hour service and increased capacity and to access new markets and growth opportunities.