A Supacheap Muni Capacity Expansion

One of my Portland friends recently posted an article entitled 25 things I wish I knew before moving to San Francisco. Astronomical rent is #3, illustrated by a map of rents by neighborhood. The blogger correctly fingers housing restrictions, linking to a Pando article which in turn links to this SF Public Press piece which is basically a bunch of people concern-trolling about whether SF can add 30% more people in 30 more years – an annualized growth rate of less than 1% per year.

I’d called this the “captain, I’m givin’ it all she’s got!” argument against future growth. And frankly, it gets old. You can build new sewer lines. Portland did. But it got me thinking.

Previously on this blog, I’ve argued for concentrating upzoning in the Sunset district. But if SF were to do this, there’d need to be a massive improvement in transit capacity through Twin Peaks. Here’s a cheap option.

Upgrade Twin Peaks Tunnel to allow 2-minute headways

Set up the signaling to allow solid 2-minute headways between West Portal and Embarcadero. (Realistically, this means a capacity for 90-second headways, to allow for recovery from delays).

Run six-car trains

If Seattle can do it, so can SF. LA runs six-car trains everywhere, and LA’s rolling stock is 22% longer than SF’s.

Switch to high platforms everywhere

This is the “low hanging fruit” as far as dwell times are concerned. When combined with 6-car trains, this would require converting a fair number of cross intersections to right-in, right-out. But platforms and intersection realignments are nothing compared to, say, a new subway.

Cannibalize Market

Currently all of the Muni Metro lines go into the Market Street subway, and then heritage trolleys operate at the surface. The heritage trolleys could be kicked off Market (relegated to the F line), freeing the surface tracks for additional LRT capacity. Routing the J-Church to the surface would free up some space in the subway. But that might not be enough. So…

Consider ending the J-Church by the naked guys

There’s an existing “Y” at 17th and Church and there’s a U-Turn at Castro and Market. This would allow the “J” to be recast as a shuttle. Which gets you a very nice…

Operating Pattern

All N-Judah trains run via the surface tracks on Market. All J-Church trains terminate at Castro. L-Taraval trains alternate with either M or K trains in the subway and Twin Peaks Tunnel. This yields:

3-minute service on the N-Judah
4-minute service on the L-Taraval
8-minute service K-Ingleside and M-Ocean View

Compared to current service, this is:

A 135% frequency increase for the N-Judah (8-9tph to 20tph)
A 90% frequency increase for the L-Taraval (8tph to 15tph)
No frequency increase for the K-Ingleside and M-Ocean View (7-8tph to 7.5tph)

Present service operates with 2-car trains on the N and L and single-car trains on the K and M, which are coupled/decoupled at West Portal. When frequency increases are combined with 3-car trains throughout the system, this yields:

A 250% capacity increase for the N-Judah
A 180% capacity increase for the L-Taraval
A 300% capacity increase for the K-Ingleside and M-Ocean View

And that’s with some platforms, some partial street closings, and some signaling upgrades. I think SF City could accommodate another half-million rather easily.

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One response to “A Supacheap Muni Capacity Expansion

  1. 1. Also, get rid of half the surface Muni stops. Currently they are about 150m apart. This is ridiculously close and does much to slow down the route as well increasing the cost of station maintenance and improvement. In other countries 500m is a typical spacing for tram stops; here it should be at least 300m. It would be much cheaper to add high-level stops if you only needed half as many of them.
    2. Is it realistic to have 3-minute service on a route without interfering too much with car traffic? Maybe 5-minutes would be more realistic, and still a big improvement over present service.

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