BART: second transbay tube?

[lpetrich]

2nd Transbay Tube needed to help keep BART on track - SFGate proposed by Zakhary Mallett, a member of BART's Board of Directors.

A breakdown or other technical problem in one of the tracks of the existing tube can force BART to run single-track under the Bay.

ZM mentioned these proposals:

More BART tracks under downtown Market Street, SF. These would have to be under the existing ones, something that will likely require deep tunnel boring. The article mentioned the tracks running alongside the existing ones in west Oakland and under the Bay, and from Civic Center, continuing underneath Fulton St. and then south under 19th St. to Daly City.

Mission St. and 3rd St. Both proposals include a tunnel under Geary St. and Geary Blvd. to west SF, and a transbay tunnel to Alameda Island. From there, it either goes to the Oakland Wye or Fruitvale station.

I'd place my bet on the 3rd St. one, because that expands the range of BART's service area in downtown SF. But Folsom St. would also be good.

[lpetrich]

Prospects for 2nd BART tube gain momentum, but wait could be long - SFGate

But despite the surge of interest, a new tube won’t arrive as quickly as anyone would like. It would take many years — perhaps 30 or more — to build political support, satisfy environmental concerns, decide where it should go, come up with many billions of dollars, and finally, build the new line. ...

A second tube would give BART, and its 400,000 daily riders, some relief. It would create a way to get around broken-down trains or other troubles in the tube. It could allow the transit system to run round-the-clock service, now precluded by maintenance needs.

Most important, it would increase the capacity of the system, which is becoming increasingly stressed by ridership that has grown much faster than BART anticipated. ...

A new tube, at this point, is an unfocused vision, far in the distance. A study of a new tube isn’t likely to start until at least 2017, when a recently initiated study of transit capacity in the Bay Area transit core — essentially the Transbay Tube, Bay Bridge and Market Street subway — is completed.

It would likely cost around $10 - $12 billion.