BART: second transbay tube?

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.

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.

This is nearly a year ago, but I found it as I was searching for other BART stuff: BART gets serious about a 2nd East Bay-S.F. Transbay Tube - SFChronicle.com

It would be the biggest Bay Area infrastructure project, probably, since the BART system was built more than 50 years ago, and it would cost twice as much as the new Bay Bridge, from $12 billion to $15 billion at a minimum.

It would go between Alameda Island and South of Market in SF, either Mission St. or AT&T Park. At the Alameda end, it would connect to the existing East Bay lines, while I don't know if it would do that at the SF end.

Seems like we have some updates, courtesy of Link21 Program | Link21

The Link21 planners seem like they are very early in planning, and they mainly state a lot of broad goals. But I've found a few things on what they have decided so far.

In Infrastructure | Link21 I find "The Key to Connection Is a New Transbay Passenger Rail Crossing". They have decided on making it a tunnel rather than a bridge, because a bridge must be very high to allow ships to pass under it.

Also discusses:

• Benicia-Martinez Rail Bridge - has a center span that is lifted for ships, impairing its reliability
• Richmond to Martinez Shoreline - very scenic, but very slow and close to sea level
• Jack London At-Grade Tracks - slow, congested
• The Oakland Wye - "All BART lines go through the Wye, a low-speed pinch point for the system."
• Downtown Extension and Salesforce Transit Center - connect it to a new transbay tunnel?

Another thread: BART, Amtrak exploring possible joint transbay crossing - RAILROAD.NET - over in the Amtrak forum (2019 and earlier)

Train Technology | Link21 - the study's authors recognize that the Bay Area has two incompatible types of regional-scale rail systems: BART and all the others ("Regional Rail"). After noting propulsion and rail-gauge differences, the page states "There are also many structural, vehicle weight, and regulatory differences between the two systems."

Light-rail systems are an additional type, but they are relatively short-distance.

This poses a serious difficulty for an additional transbay tube. Will it be BART-only? Regional-rail-only? For both BART and regional rail?

If it is BART-only or BART+RR, then that raises the issue of how it is to connect to the East Bay BART lines. Avoiding the Oakland Wye would be good to do, but that raises the question of what line to connect to? The Fremont Line? The Richmond Line? The Concord Line? Just south of MacArthur?

Well and if it goes to the new transbay terminal, where does it go after that?

Also I don't understand how Amtrak could use this without new equipment. There is no electrified Amtrak service in California.

Caltrain will eventually be using Transbay date sometime. So, no problem there as could be thru service but who knows. Equipment? Same answer these new tubes will be at least 15 years in the future. Too many variables.

Less we forget . If the tracks are shared gauge then very possible that CA HSR would use the tubes to continue from Transbay to Oakland and beyond. In fact on further consideration more likely CA HSR would use the tubes rather than Amtrak.

west point wrote: ↑Sun Apr 03, 2022 2:16 am Caltrain will eventually be using Transbay date sometime. So, no problem there as could be thru service but who knows. Equipment? Same answer these new tubes will be at least 15 years in the future. Too many variables.

Less we forget . If the tracks are shared gauge then very possible that CA HSR would use the tubes to continue from Transbay to Oakland and beyond. In fact on further consideration more likely CA HSR would use the tubes rather than Amtrak.

I'm confused, what does Caltrain have to do with BART?

CA HSR can't even build a straight section through the central valley on time, how on earth are they going to now electrify tracks and apparently run through service?

west point wrote: ↑Sun Apr 03, 2022 2:16 am Less we forget . If the tracks are shared gauge then very possible that CA HSR would use the tubes to continue from Transbay to Oakland and beyond. In fact on further consideration more likely CA HSR would use the tubes rather than Amtrak.

Shared gauge with BART???

First look at BART's 2nd Transbay Tube renderings - KTVU Fox 2

Check ‘Em Out! We Have Our First Renderings of the Second Transbay Tube - "A longtime BART fan fantasy is coming to life, as a second Transbay Tube gets its first proposed public renderings, though there are a couple proposals, and it probably won’t be operating until 2040 at the earliest."

I looked in Link21 Program | Link21 and I could not find any reference to those plans, and likewise for Projects - Capitol Corridor and Projects & Plans | bart.gov. Those two sites linked to the Link21 site.

The new transbay tube will include a second crossing for BART and a crossing for regional rail (Caltrain, Capitol Corridor, etc.)

The renderings show two configurations for the new transbay tube: two separate tubes, one each for BART and RR, and a combined tube for both. Each of the separate tubes will likely be like the existing BART transbay tube, a pair of single-track tubes. The combined tube will have likely have four single-track tubes, two each for BART and RR.

The BART line will branch off a little south of MacArthur, and will have a possible downtown-Oakland station, a Jack London Square station with a relocated RR station, a possible Alameda station, and a Salesforce / Transbay Transit Center (TBT) station, with an option to continue westward. BART may also get a San Antonio station between Lake Merritt and Fruitvale stations.

The RR line will get a station at the West Oakland BART station and one at the TBT.

For separate tubes, BART may get stations at Mission Bay and at 4th and King, while for shared tubes, RR may get a station shared with BART in Alameda.

Any project will require at least 2 separate tubes. They would have a escape route between the tubes about every 800 feet. That because of national fire codes. Forget number.

Semantics. It's one tube with multiple chambers, and compliant with fire and seismic codes...

https://designarchives.aiga.org/assets/ ... 273_or.jpg

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west point wrote: ↑Mon Sep 26, 2022 2:25 am Any project will require at least 2 separate tubes. They would have a escape route between the tubes about every 800 feet. That because of national fire codes. Forget number.

That's a rather nitpicky design detail, and it does not affect the essential content of what I posted.

https://sf.streetsblog.org/2023/01/17/o ... do-better/

Pursuant to our review, the following are questions in need of answers before substantial additional consultant work is done. Here are some issues that are, or at least should be of immediate concern:

Post-COVID, the permanent long-range changes will likely include a permanent shift to work-at-home for at least three days a week for many categories of employees, a dispersion of both residents and places of employment away from cities, and a resulting drop in the level of activity of San Francisco’s financial district. BART’s pre-COVID ridership was about 450,000 riders a day. Today’s ridership is running about half that many. What amount of total Transbay BART ridership would justify a $30 to $40 billion second rail tube? Has your original plan for Link 21 been modified to reflect currently anticipated conditions? Does the Region still even need a second tube? If so why?
For the Regional Rail alternatives, the Salesforce Transit Center is obviously the most effective West Bay point of connection. Salesforce has been listed as a connection alternative, but with the warning that “costs could be prohibitive”. It is essential that this question be answered immediately. ARUP [engineering] is already well aware of the nearby geotechnical and structural conditions and therefore probably already has a pretty good idea of the extent and cost of making this connection.
Is the BART Staff seriously considering sending both BART and standard gauge trains under the Bay? If so please enumerate the advantages of so doing. (Excellent BART-to-standard-gauge connection opportunities exist on both sides of the Bay)
In the BART and Combined alternatives BART is shown as extending under Market Street, but where under Market? At what location? To where? Could you be more explicit? How would extending BART beyond Salesforce affect the cost of the project?
In the BART and “Combined” alternatives it is proposed to relocate the Jack London Capital Corridor Station to connect directly with a new Jack London BART station. Can a BART/CC transfer station be fitted in under JLS? What would be the cost of adding this station?
How would the proposed BART/Capital Corridor Coliseum transfer be improved?
In Combined B, why is 4th and King listed as a possible transfer station?
Regional B, designates an “improved” Capital Corridor Jack London Station. Improved how?
Serving Alameda is listed as an alternative. How many projected riders would be added by placing a rail station in northwestern Alameda? At what additional cost?
In BART A and Combined A you show a connection between BART and the Salesforce Transit Center. There are at least three different ways in which a BART connection could be made. Please be more explicit.
The need for equity is repeatedly emphasized. With the rail routes and stations already largely in place, other than discounted fares for lower-income people, what does the term “equity” in this context mean?
“Cost Containment” has been emphasized. Cost containment how? Please outline at least 10 areas of opportunity.
In excess of $65 million has already been spent on the Link 21 project. Other than a preliminary marketing plan and the six sketch alternatives, what are the products of this expenditure?