A second transbay tube for BART? It could happen

A train approaches MacArthur BART Station on Friday, November 2, 2018 in Oakland, Calif. A train approaches MacArthur BART Station on Friday, November 2, 2018 in Oakland, Calif. Photo: Amy Osborne / Special To The Chronicle Photo: Amy Osborne / Special To The Chronicle Image 1 of / 1 Caption Close A second transbay tube for BART? It could happen 1 / 1 Back to Gallery

Bay Area Rapid Transit officials will present their latest plans Thursday to build a second Transbay Tube connecting San Francisco to the East Bay — and perhaps start 24-hour service.

The idea has been in the works for a while, and if it all goes according to plan, BART would begin construction on a second transbay connector in 10 years. BART tweeted about the presentation Wednesday night, saying “BART is taking early steps to create a second Transbay Tube; although we are calling it the second Transbay Rail Crossing for now.”

A second crossing would double capacity and improve connections with other rail systems, officials say. It’s unclear when the system could move to 24-hour service, if at all.

Officials released some details Wednesday afternoon, but said they intend to award a contract to an organization to conduct a “feasibility study to narrow multiple alternatives” for the crossing to a list of two to four options.

BART officials could not be reached for comment Wednesday night.

BART’s Twitter account went as far as sharing a photo illustration of a BART train traveling on the underside of the Golden Gate Bridge, prompting dozens of Twitter users to express their excitement, opinions and bewilderment.

The second rail crossing connecting San Francisco to the East Bay is not a new conversation among riders and transportation officials.

In early 2018, BART planning officials agreed it would be important to speak with San Francisco, Oakland and Alameda County officials about how future riders could connect to housing and jobs before even analyzing the potential tube’s location and alignment.

Transit officials assured riders in a lengthy Twitter thread Wednesday night they would coordinate with other transportation and city agencies including AC Transit, Caltrain, SFMTA, the Water Emergency Transportation Authority and others.

In a 15-page presentation detailing the rail crossing, BART officials project more people will want to cross the bay by 2040 than can be accommodated by the current system.

“Despite BART’s plan to increase capacity through the existing Transbay Tube, planners project demand for transbay transit will outpace capacity by 2040 in medium or high demand growth scenarios,” read a BART statement.

The BART board of director’s meeting will be streamed online at https://www.bart.gov/about/bod/multimediaat 9 a.m. on Thursday.

Lauren Hernandez is a San Francisco Chronicle staff writer. Email: lauren.hernandez

@sfchronicle.com Twitter: @LaurenPorFavor