November 16, 2010

(Duplicate?) Underground Rail Galore Planned in SOMA, South Beach

The San Francisco MTA is looking a few million short for their planned central subway. The subway would connect the existing Caltrain terminal at King and 4th with light rail service above ground to Bryant and 4th (by the looks of the map) and then underground to Chinatown.

The proposed additions

What is unclear is how this plan will connect with the Transbay Terminal, a project that is much more likely to move forward, since the previous Terminal has been demolished--buses are currently using a temporary structure. According to the Transbay Terminal project map (also below) on the website, the new Terminal will be bounded by Mission and Howard, and 2nd and Beale. So, far enough away from the black line on the above map that the central subway will not pass through the Transbay Terminal.

Additionally, the Transbay Terminal proposes building an underground right of way from King and 4th to the 2nd and Howard/Mission. This would serve as the SF terminus for high speed rail.

"The rail line will be extended 1.3 miles underground from its current terminus at Fourth and King streets into the new Transbay Transit Center, providing a seamless connection between the Peninsula, the South Bay, Southern California and San Francisco’s Financial District."

So to pull this together: HSR and Caltrains will come through the 4th and King station, and continue underground to the Transbay Terminal (blue line above). The 4th and King station will also have a branch northwest along 4th street, taking Muni light rail aboveground to Bryant, then underground to Chinatown.

I wonder how the underground subway would connect with existing Muni subway running along Market Street ... (update: commenter lmz informs that the Union Square Central Subway stop would have an underground ped connection to the Powell St station)

Also, can a high speed rail train execute a 90 degree turn? Maybe the right angle is an exaggeration of the publicity map; these are obviously not engineering specs, and it will be underground in any case (and thus not constrained by street grids).

Both of these projects are "actively searching for funding." Especially the central subway, which is more tenuous. If rail service is already being extended from 4th and King to 2nd and Mission, does it also need to go up to Chinatown along a separate route? Wouldn't it be better to extend, later, northward from the Transbay Terminal? I must be missing something here.


  1. "The 4th and King station will also have a branch northwest along 4th street, taking Caltrains aboveground to Bryant, then underground to Chinatown."

    The Central subway is not Caltrain, it's Muni light rail. It's actually an extension of the T-Third line coming up 4th street from Sunnydale (the pink line in the map). And it will have a station at Union Square / Market Street with an underground passage to the Powell Street BART/Muni Station.

    They're not really redundant services, they are continuations of existing services. Also the Central Subway could someday go up further, into North Beach, whereas the Caltrain/HSR doesn't really make sense to go further north; it's heavy rail so a downtown terminus makes the most sense.

  2. lmz, thanks for the feedback. Caltrain/Muni light rail noted. And I absolutely agree that Caltrain/HSR logically terminate at the Transbay Terminal.

    I guess what I was getting at was the (in)efficiency of creating two underground right of ways, given the cost of tunneling, etc. And since it is arguably more important to connect 4th and King to the Transbay Terminal to create the HSR/Caltrain terminus, investing similar amounts to link the central subway to 4th and King seemed simply less urgent. But you make a good point that both projects would continue existing lines.

    Another commenter on Streetsblog raised the issue of whether the central subway should even connect with Caltrain and HSR at 4th and King in the first place--why not at the Transbay Terminal. If the Transbay Terminal is to be the Grand Central Station, shouldn't it be the starting point for the Muni light rail subway, and not 4th and King?

    At the risk of spinning this discussion too far out into transit dream world, what do you think is the ideal central subway alignment?