A downtown subway grid

Recently, the SFCTA, SFMTA and various other transportation organizations released a website called Subway Vision. It aims to collect ideas from everybody about where to install new subways in SF. The Subway Master Plan is supposed to ensure that we are always building a subway, and we currently have the Central Subway under construction, along with planning for the M subway and construction hopefully in the not-too-distant future. Future expansion plans are also being considered right now, as the Rail Capacity Strategy report released back in February gives an outline of what Muni thinks its next steps will be.

People spend a lot of time talking about Geary whenever new subways are discussed. And that’s great! Having high-capacity transit on Geary is extremely important given that its bus lines ferry the same ridership as Caltrain. BRT will definitely help, and we’ll see how this develops in the future. However, I think the need for new subways downtown is often overshadowed by this discussion. Our current rail network has one subway that goes from downtown outwards, through which a large percentage of its 150,000 daily riders go. This is a huge bottleneck! Problems that occur in the subway here are liable to delay many people and cause lots of gaps and bunches. If there is one thing we can learn from New York here, it is that these problems are way more tolerable when there is some redundancy.

Having extra subways parallel to the Market Street Subway downtown is hardly a new idea. SPUR advanced the idea in this report and has implied it in various materials concerning a second Transbay Tube. By pulling together some ideas from these and the Rail Capacity Strategy, we can come up with a nice grid-like structure for subways in downtown SF.

First, if we look at the Rail Capacity Strategy, we find that Muni eventually wants to put LRT on Geary. LRT will improve capacity even more than BRT, but the most interesting part about the plan is the fact that it might be a hybrid subway/surface line. Muni gives cost estimates for all of the involved projects in the report, and the lowest estimate for Geary LRT appears to be the cost of installing surface rail along its entire length at a cost of about $1.4 billion. By using the estimated cost of installing other subways and doing some math, we can figure out that the $3 billion upper bound makes sense if Muni installs a mile of subway and 5 miles of surface rail. One mile of subway takes us from Market to about Van Ness along Geary, which is a reasonable option.

But why should we stop at Market? Merging into the Market Street Subway is probably not feasible, since it’s not possible to fit a flyover junction when there is already another subway below. Even if it were possible, it would probably be ill-advised, as we’d get one extra stop at the expense of subjecting the new subway to all of the same problems we get by combining the other lines. But there are other options—the report also has lots of figures for job and population density in various sections of the city, and we can use those to extend the route. 2nd St in particular has a very high density of both, and a subway in the Geary area could connect through Mongtomery Station and continue into SoMa along 2nd St. This line could be anchored at AT&T Park, which is surrounded by a commercial district, and which often relies on the easily-overwhelmed Muni Metro Extension to get people in and out on game days. 2nd St is also slated for an upgrade to LRT in the distant future, according to the Rail Capacity Strategy.

It might seem like overservice, and while the redundancy with the Central Subway is nice, that’s not really what we’re after. The grid really comes together when we install a subway along Folsom. Folsom is considered one of twelve high-priority corridors for expansion by Muni. By pulling a line out of the Market Street Subway between Church and Van Ness and instead sending it up Folsom, we solve a number of problems:

  • Fewer lines are merging at Van Ness, which means we can mitigate a bottleneck there
  • The already-existing flyover junction would make construction of the other one less disruptive, since we wouldn’t have to reconfigure the current subway
  • In the event of backups in the Market Street Subway, all KLM trains could reroute into the Folsom Street Subway instead, mitigating delays (J and N trains could stop at Church & Duboce for transfer) and still allowing decent access to Montgomery and Powell areas via the 2nd/Geary and Central Subways

In this proposal I choose the L train to be pulled out in standard service because we can’t pull out the J or N, as the new trains will leave the MSS before the J or N merge in; the M is going to improve capacity in the MSS after its subway expansion and use of longer trains, which is important; and the K can only run short trains at the time being, and may still be used to serve the Muni Metro Extension.

The end result is a grid-like structure centered on 2nd, 4th, Market and Folsom Sts, with additional transfer points along the Embarcadero and on King. Here’s what it looks like:

names
Above-ground stops are circled with gray, and Van Ness BRT is shown as the green dashed line.

There’s also room for further expansion: Leavenworth, Civic Center and 7th St stations all line up quite nicely, for instance (and would be easily connected by the bus I laid out in earlier articles). If the Caltrain railyard is rebuilt underground and the 280 spur is at least partially torn down, this could open up enough land that extending the Muni Metro Extension out to 7th St and building more rail along 7th St makes sense, as well. Some ideas for extending high-capacity transit along Van Ness send it down 11th St and Potrero Ave, in which case they would also fit nicely into this grid; extensions down Mission could also use the transfer to the new station at Duboce Ave. Sadly, I think the Chinatown T stop is too far north to have a really easy transfer, but a line down Sacramento St might be useful and connect Van Ness BRT with Embarcadero and Main St Stations. The T would be within reasonable walking distance of such a line.

This expansion provides a lot of extra options for people to move around on corridors that Muni considers important, and getting them into a shape where they work well together. Having redundant infrastructure makes the system more resilient and also makes it easier to justify arbitrary planned service changes, which people will need to deal with if we ever eventually want 24-hour rail service.

But don’t just take my word for what subways are worthwhile to build. With Subway Vision, Muni is giving all of us an opportunity to influence the evolution of the city. We should use this opportunity to tell them what we think!

The one-seat slowdown

In the article about the 19th Avenue Subway, I wrote briefly about the plans for the J to cover the portion of the M route in Ocean View (Randolph, Broad, and San Jose). Residents of Ocean View are now faced with a trade-off when trying to get downtown. They will experience a faster ride if they take the J to SFSU Station and transfer to long, fast M trains to continue inbound. However, some people are not happy about the loss of a reasonably quick one-seat ride, since their current route will be replaced with the J coming all the way around through Balboa Park. The J is going to spend a lot more time in mixed traffic than the M does currently, and so taking it downtown from Ocean View is likely to be a slow and unreliable ride. While we should think about what will keep the J reliable, we might also want to consider doing something else to mitigate the concerns of Ocean View residents.

Let’s take a look at the N. A large percentage of this route is at-grade, and getting from one end to the other is very slow. This sounds familiar! During commute hours, when subway space is limited and people from the forties need to get downtown in a reasonable amount of time, Muni runs an express route along this line. The NX-Judah Express aims to get people from further out to downtown quickly by skipping lots of stops in the middle and using faster one-way, timed-light roads where possible to keep the buses moving. Plenty of bus routes have matching express routes during commute hours. The 1-California and 38-Geary each have two express routes which use Bush and Pine to get downtown quickly. The 7X-Noriega Express uses Oak, Fell, Franklin, Gough, Golden Gate, and Turk. Express routes for the 8 and 14 use freeways. But most light rail lines do not need an express route since the subway generally obviates the need for them. To support a light rail express line, we need to be able to get people from far-flung areas onto fast roads and keep them there until we get close to downtown. With the J extension to SFSU, the line might become eligible for such treatment.

280 and 101 can be used to transport people express from the Glen Park areas to downtown more quickly than it would take to crawl all the way around and finally get into the subway. Stops between 19th Ave & Randolph St and San Jose Ave & Santa Rosa Ave would be serviced by the express bus, after which it would take 280 via Baden and either Circular Ave or Monterey Blvd. From there, it can get on 101 via the Alemany Maze interchange. The Central Freeway will allow the bus to exit on Mission to service Van Ness & Market. The bus can make normal J stops up Market from there. (Other designs might make different stops downtown or use a different route to get there, as the NX tries to serve the Financial District more specifically. I tried to make this serve existing downtown J/M stops as closely as possible.)

map

Now that the JX services stops up to Santa Rosa, we can turn around more J trains at Glen Park. This already happens during commute hours, but it’s rare, and with the JX to supplement service past Glen Park we will be able to get away with turning some trains around more quickly than we would be otherwise. This would help keep the route more reliable for residents further inbound on the route.

Of course, there are other concerns at play here. I don’t normally like introducing express buses, because they are an expensive proposition with regard to how much service they actually provide. Muni will be forced to increase its peak bus fleet to accommodate the extra commute-time load. The J station at Glen Park is somewhat confusing if trains are turning back there, since trains can’t cross over to the inbound track from the outbound side. I’m not sure how expensive installing this extra track would be. Furthermore, extremely heavy traffic on the freeways may mean the bus won’t save any time after all! However, if this idea gets more people on board with the 19th Avenue Subway by assuaging concerns over the reliability of the J and preservation of a somewhat quick one-seat ride to downtown from Ocean View, then I think it’s worth studying.

The 19th Avenue Subway

The Market Street Subway is a bottleneck for the Muni Metro system, since each of its lines eventually merges into it. Early documents show plans for a four-track subway under Market; alas, we didn’t commit to that project and now we are stuck with a two-track subway. Combine this with the fact that the surface segments of each line force Muni to run one- and two-car trains where the stations could handle a lot more and it’s easy to see that we’re leaving tons of capacity on the table.

The Central Subway pulls half a line out of the Market Street Subway, which probably won’t improve the situation since we still have five lines in the subway at all times. In addition, the new Parkmerced developments are going to add thousands of daily riders to the M Ocean View line, which runs in mixed traffic on 19th Ave and is prone to some of the worst gaps and delays in the whole system. Muni decided to look at improving this line next. They did some studies, offered some suggestions that seemed lacking in the long term, and collected a bunch of community feedback.

Last month, something interesting happened: Muni greatly increased the scope of the project. The details can be found here, and I encourage you to go read those before I poison your thoughts with my editorializing.

If completed, Muni will have built its first fully grade-separated metro line, and it would improve the situation throughout the system. The M would be free of just about all gaps and delays, and it would use 4-car trains, greatly expanding the capacity of the Market Street Subway. West Portal will be able to handle many more trains and people. St. Francis Circle will be free of the crazy signaling, the intersection will be less complicated, and pedestrians will be able to make more use of the metro there. 19th Avenue will generally become more pedestrian-friendly and the line will better serve SFSU and Parkmerced. It’s a fantastic proposal, in my opinion. There are a few interesting details I’d like to point out as topics for further discussion or clarification.

J Ocean View

If this project completes as planned, the J will take over service in Ocean View. (We might need to rename some lines, but I digress.) The choice of the J to take over this part of the journey is interesting because it has a number of features limiting its capacity at the moment. One of the more frustrating issues with the J is the inability to run even 2-car trains along the line, because some of the stops would render the second car inaccessible. However, the plan explicitly talks about running 2-car J trains. Muni plans to remove one of the problem stops (Liberty St on the private right-of-way), but I’m not sure that this is the only one (21st St might be too short, and possibly Glen Park). This might boil down to adding a few square feet of concrete here and there, but it’s something that Muni hasn’t mentioned to date in its other Muni Forward plans.

This also means that the J will spend a much higher percentage of its time above ground and in mixed traffic, since it doesn’t look like there are plans to give it a red lane south of 16th St. This might not be an issue for Ocean View commuters trying to get downtown because I assume they will take the J outbound to SFSU Station and transfer over to the M, and it will probably be faster than what they have now. However, we have to be careful that we aren’t getting rid of delays on the M by simply passing them on to the J. The J will need extra reliability improvements so it can remain a useful part of the rapid network.

The Curious Case of St. Francis Circle

If you look at the rail map in the project details, you might notice the very strangely laid out subway station at St. Francis Circle.

st-francis-circle.png

At first, I took this to mean that the M trains coming through would always stop on the west side of the platform no matter which direction they are headed towards, and similarly for the K on the east side.

one-level-platform

This seemed like a strange interpretation because Muni is making this immense capital expenditure to get rid of delays and yet this seems like it might cause a lot of them. This limits the maximum frequency of trains through St. Francis Circle because they must maintain stopping distance while a train from the other direction is passing through. It also means that the M and K have the same maximum frequency in the station, which is not the most efficient way to do things—as extra capacity is needed, it would be more useful to swap out K trains for M trains and have some K trains terminate at St. Francis Circle. Riders could then transfer to the longer M trains for the rest of the journey. The K seems to have the same problem as the J in that it can’t support trains longer than 1 car, so running more frequent M trains through seems like a no-brainer.

I did some digging around in NYC Subway track maps to see if I could find an analog for this sort of station, and the closest thing I found was Queensboro Plaza:

queensboro-plaza

From the map alone it seems like Queensboro Plaza is structured the same way, with one track going through the station for the 7 and <7> and the other track for the N and Q. This doesn’t make sense when you’re running trains every two minutes in both directions. However, Queensboro Plaza is actually a two-level station, where the Manhattan-bound trains from each line stop on one level and the outbound trains stop on the other level. Each train has two tracks going through the station. It’s possible SFMTA is planning a similar structure for St. Francis Circle station!

two-level-platform

The structure is a bit harder to see here, but the western side of the station would have M trains, and the eastern side would have K trains. This would allow them to run trains in both directions without a bottleneck, and would provide a way for the M and K to cross over each other without sharing a single switch. There are some drawbacks—building this station and track layout is probably way more expensive than the one-level layout, and the inbound and outbound tracks for each individual line don’t actually meet anywhere, meaning we couldn’t terminate K trains at this station like we wanted to. In the one-level world, we can pull a train into the station and just back it out when it’s ready to turn around. With the two-level design, we’d probably have to run them to West Portal and turn them around there, which defeats the point. (This might still help since we can pull the K trains back before the L trains merge into the subway towards Forest Hill, but M trains might be stuck waiting for K trains to turn around at West Portal anyway.)

I guess the moral of the story here is that I’m not really sure what they want to do with this station, but the track layout they’ve picked makes me a little worried that we will again run into capacity issues sooner than we’d like.

The Daly City Extension

The plan leaves room for the extension of the subway to Daly City BART. BART and Muni already have plenty of connections at Balboa Park, but this one would be pretty useful because data from the Transit Effectiveness Project/Muni Forward on how people use the 28 and 28R (formerly 28L) show that Daly City BART is a good anchor for the line. Linking SFSU with Daly City by a direct subway connection is probably a really good idea since those are the busiest stops along the corridor.

This would also offer a kind of redundancy with BART in that there would be two discrete grade-separated lines from Daly City to Embarcadero, which would improve the resilience of the whole system in San Francisco. If BART is having problems in the city, the M might be a good substitute for people commuting up from the south. Of course, this might cast the lack of integrated fares into sharp relief, but that’s a much more complicated issue for another post.

Similarities to New Muni Metro

Back at the end of 2014, Nextransit published the first part of their New Muni Metro plan. The principles behind the Ocean View plan and the New Muni Metro plan are similar, though New Muni Metro didn’t expect to launch into multi-billion dollar capital projects for a long time. But they realized that we already have a fully-grade separated line if we end the Market Street Subway lines at West Portal. All of the other lines are streetcars only and people transfer to the Market Street Subway at West Portal (K, L, M), Church (N, J), or Embarcadero (T). The New Muni Metro plan also involves some line fusion, with the J taking over the surface portion of the K, and the L taking over the surface portion of the M. This means we could run all of the surface lines more often without worrying about whether we’re overloading the subway, and the subway will be able to run longer trains all of the time because there won’t be any short stations along its path. Higher surface line frequencies plus long, extremely frequent subway trains will mean way more capacity and generally shorter trips, even if you have to transfer.

I think the most interesting part about the similarity is that it means Muni could probably experiment with this same kind of service, should capacity become an issue. I alluded to this in terms of substituting K trains for M trains in the St. Francis Circle station design, but we could theoretically do this with any type of train. Forcing people to transfer probably wouldn’t make everyone happy, but the trains would be less crowded this way, so it might work out!

However the details fall out, this is incredibly exciting news. Transit agencies often avoid making grand plans like this because the funding for grand plans has dried up, but if we know that we’ll be getting something this useful out of it, the political situation might be workable after all. We shouldn’t be afraid to dream big—even if these projects seem expensive, they’re necessary, and nobody will look back on it in the future and think it was money poorly spent. Let’s see how Muni builds on this in the coming years!