Construction workers build BART's transbay tube in 1970. Local think tank, SPUR, says the Bay Area will need another transbay tube with the Bay Area's population set to boom over the next two decades. (Courtesy Bechtel Corp.)

Construction workers build BART's transbay tube in 1970. Local think tank, SPUR, says the Bay Area will need another transbay tube with the Bay Area's population set to boom over the next two decades. (Courtesy Bechtel Corp.)

Think tank calls for second BART transbay tube

Between 1966 and 1969, California officials built what was the world’s longest and deepest underwater tunnel: the Bay Area Rapid Transit transbay tube.

A trench 133 feet deep was dug in the Bay. Barges ferried 57 sections of the California-built tunnels to the briny blue. The tubes were sunk, one by one.

Mud was poured atop steel, and in 1972, BART was born, whisking thousands of passengers in trains underneath the Bay.

Now, the Bay Area is being called upon to build another transbay tube.

A new report released Wednesday by policy think tank SPUR says if a second transbay tube connecting San Francisco to the East Bay is not built, BART may exceed capacity by 2024.

That may snag drivers, too, as the region’s highways continue to clog.

The report, called “Designing the Bay Area’s Second Transbay Rail Crossing,” says the new tube could address Bay Area connectivity on other rail systems, like CalTrain, if it integrates different types of tracks.

Ratna Amin, a co-author of the report from SPUR, called the warning of BART’s crush capacity “a moving target.”

Still, the number isn’t out of thin air. The Bay Area Core Capacity Transit Study estimates future transit improvements will allow the transbay system (including ferries, AC Transit buses and BART) to handle a maximum of 51,000 daily morning riders.

Transbay systems currently handle 27,300 daily riders each morning.

But the Metropolitan Transportation Commission estimates current population growth trends show transbay morning ridership will reach 51,000 passengers by 2024.

The report suggests the BART cars of 2016 may seem blissfully spacious compared to the cramped conditions of 2024.

“There will be a time when there is absolutely a need for a second tube,” said Ellen Smith, BART’s manager for strategic and policy planning.

Perhaps the most crucial deadline is the impending reconstruction of the original transbay tunnel that, though planned, as of yet has no firm date.

“We’ll have to take it out of service for significant time to rehabilitate it,” Smith said.

Without a second tube, transbay access will be limited.

The report outlines other disadvantages of operating only one transbay tube: Small disruptions can block the connection between The City and East Bay, and system reliability is in steep decline.

A second tube would also enable BART to run all-night transit. Right now, BART ends service near midnight for maintenance.

On the heels of SPUR’s report, the Bay Area Council released an analysis of their own on a second transbay tube. Bay Area businesses would translate into “significant productivity gains” the council said.

“The transbay crossing is the lynchpin of our economy, but it’s fast becoming the choking point,” said Dr. Micah Weinberg, President of the Bay Area Council Economic Institute, in a statement.

Planning may take 20 to 30 years once started, according to the report. Some infrastructure experts told SPUR it could be completed within 10 years if political leaders took “extraordinary steps” in funding.

Smith said there is some limited planning taking place right now. The MTC, BART, and politicians in Oakland and San Francisco are all looking at a future transbay tube.

But the report highlights the need for a regional or state agency to spearhead the project.

So far, that has not happened.

“I intend to push hard to move toward a second transbay tube, and it’s a very high transit priority for me,” Supervisor Scott Wiener told the San Francisco Examiner.

“This isn’t simply a BART project, and we can’t just expect BART to deliver the project on its own,” Wiener said, adding the MTC is one likely regional leader of the project.

BART has more short-term worries, Smith said.

The agency is “putting our energy, our funding, at our core needs, which are experiencing capacity constraint,” she said.

BART’s Board of Directors is debating whether to seek a bond between $2.5 billion and $4.5 billion to keep the system in a state of good repair.

The original BART system was built for $1.6 billion, according to the report. Smith said it was “too early” to even guess at cost or timeline for a second transbay tube.

Planners also haven’t decided on how it should be built. The report outlines a few methods — a submerged tunnel, like the current tube, is one idea. But the cost of boring through earth “has become much cheaper in recent decades,” according to the report, and is another possibility.

The report discusses an elevated rail bridge as well — perhaps an outrageous idea to some.

But the BART tube itself was also once considered a pipe dream.

In 1964, President Lyndon B. Johnson flew to Concord for the groundbreaking of the new-fangled BART system.

The June 19, 1964, edition of the San Francisco News-Call Bulletin wrote of the event: Johnson “told an enthusiastic throng of Eastbay [sic] residents the decision to undertake the $1 billion, 75-mile system was a ‘victory of vision.’”

The president continued, “I do not believe the American people want to run a losing race with change.”

BARTMetropolitan Transportation CommissionSupervisor Scott Wienertransbay tubeTransit

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