RPA Fourth Regional Plan: the Third Avenue Trunk Line

Based on a Patreon poll, the top two priorities for this blog for critiquing the RPA Fourth Regional Plan are its mess of the LGA connection and the Astoria Line, and the proposed commuter rail trunk line on Third Avenue. The third priority is multi-tracking existing lines and timetable-infrastructure integration.

New York’s existing regional rail network suggests a north-south trunk line, starting from the Harlem Line in the north and continuing south to Lower Manhattan and beyond. Such a line would run parallel to the Lexington Avenue Line, providing additional express service, running fast not just between 125th Street and City Hall but also farther north and south. Going back to 2009, I have proposed such a line, controversially continuing on to Staten Island:

Of note, the depicted regional rail network makes use of the entirety of Grand Central’s approach tracks. There are four tracks, two used by Line 2 to Penn Station (the green line) and two by Line 4 (the blue line), the north-south trunk under discussion. In contrast, here is the RPA version:

There is a lot more going on in the RPA version – more tunnels, some light rail lines – but the important thing to focus on in this post is the north-south trunk. The RPA is proposing the following items:

  1. A north-south trunk line under Third Avenue, with an onward connection to Brooklyn.
  2. Stops at 125th, 86th, 42nd, 31st, 14th, Canal, and Fulton Street.
  3. Two tunnels to New Jersey (in addition to Gateway), at 57th and Houston Streets, using Third Avenue to connect between them.
  4. A tunnel directly under the Harlem Line in the Bronx, called an express tunnel but making more stops, with infill at 138th and 149th Street, to intersect the 6 and 2/5 trains respectively.

I contend that all three elements are problematic, and should not be built without major changes.

1. Third Avenue

The RPA plan bypasses the existing tracks to Grand Central entirely. This simplifies scheduling, in the sense that all trains using Third Avenue are captive to the reorganized system from the start. It also serves the Upper East Side and East Harlem slightly better: there is more population density east of Third Avenue than west of it, so it materially benefits riders to have a commuter rail station on Third rather than on Park, where the current line goes.

Unfortunately, these advantages are swamped by the fact that this means the Fourth Regional Plan is proposing about 8 kilometers of tunnel, from 138th Street to 42nd, redundant with the existing Grand Central approach. At the cost I think is appropriate for urban tunnels, this is around $2 billion. At what New York seems to actually spend, start from $13 billion and go up.

Because this trunk line would have to be built from scratch, it also has necessarily limited capacity. The Grand Central approach has four tracks; Third Avenue is as far as I can tell based on the plan just two. Many trains on the Hudson and New Haven Lines would need to keep terminating at the existing Grand Central station, with no through-service; any transfer to the Third Avenue trunk would involve walking a long block between Park and Third Avenues, 310 meters apart.

The capacity limitation, in turn, forces some reverse-branching onto Metro-North, on top of that coming from future Penn Station Access lines (the connections from the New Haven and Hudson Lines to Penn Station, depicted on both the RPA map and my map). It is possible to avoid this by connecting just one of Metro-North’s line to the new trunk, probably the Harlem Line, and then make passengers from the other two lines go to the existing Grand Central. But at least as depicted in the map, this service pattern seems unlikely: the High Bridge infill stop suggests some Hudson Line trains would go to the trunk, too. Unfortunately, even without reverse-branching, service would not be great, since connections between the old and new system (especially with the Hudson Line) would require a long walk at 125th Street or Grand Central.

The long walk is also a problem for the trunk line from Grand Central south. According to OnTheMap, the center of gravity of Midtown jobs seems to be between Fifth and Sixth Avenues, with few jobs east of Third. While this trunk line is good for scooping Upper East Side passengers, it isn’t good for delivering them to their exact destination.

2. Stop Spacing

The RPA stop spacing is too local. The 4 and 5 trains stop at 125th, 86th, 59th, Grand Central, Union Square, City Hall, and Fulton Street. It’s for this reason that my map’s Line 4 is so express, stopping only at 125th Street, Grand Central, Union Square, and Fulton Street: the line parallels the Lexington Avenue Line so closely that it should offer a different stopping pattern. For the same reason, observe that I do not include any infill on the LIRR Main Line west of Jamaica, where is it closely parallel to the Queens Boulevard Line with its E and F express trains; on lines not so close to express subways, I have extensive infill instead.

In contrast, the RPA wants trains to make the same number of stops between Harlem and Lower Manhattan as the 4 and 5 subway lines, just at slightly different locations: 31st instead of 59th, Canal instead of City Hall.

The Canal Street location is understandable. Chinatown is a major destination, overshadowed by Midtown and Lower Manhattan but important in its own right; the Canal Street complex on the 6, N/Q/R/W, and J/Z is the 18th busiest subway station in New York on weekdays and the 11th busiest on weekends. It’s also an intersection point between the north-south trunk line and the N/Q trains (in addition to Union Square) and the J/Z trains (in addition to Fulton Street). I think it’s overall not a good idea to include this location, because the 4/5/6 exist, and the connections to the N/Q and J/Z also exist elsewhere, but I think the alternatives analysis for this project should include this station as an option.

In contrast, 31st Street is inexcusable. On the surface, the rationale for it is clear: provide a transfer point with the east-west tunnels feeding Penn Station. In practice, it is weak. The area is just frustratingly out of walking range from Midtown jobs for train riders. The transfer is good in theory, but in practice requires a new tunnel from Penn Station to Long Island, one that the RPA included because Long Island’s turf warriors wanted it despite complete lack of technical merit; the cost of this tunnel, according to RPA head Tom Wright, would be $7 billion. The only reason to include this connection in the first place is that RPA decided against a connection between Grand Central and Penn Station.

3. The New Jersey Tunnels

In New Jersey, the RPA believes in making no little plans, proposing three two-track Hudson crossings: Gateway, and two new tunnels, one connecting Bergen and Passaic Counties with 57th Street, and one from Hoboken to Houston Street. Tunnels in the general vicinity of these are good ideas. But in this plan, there’s one especially bad element: those tunnels link into the same Third Avenue trunk line.

The RPA has a tendency, going back to at least the Third Regional Plan, to hang many elements on one central piece of infrastructure. The Third Plan proposed Second Avenue Subway as a four-track line, with many branches hitting all the other priorities: regional rail, an express rail connection to JFK, more lines in Brooklyn and the Bronx – see schematic on PDF-p. 13 of the executive summary and more detail on PDF-pp. 204-207 of the full plan. Most of these elements were good on their own, but the connection to Second Avenue Subway made them more awkward, with extensive conventional- and reverse-branching, and a JFK connection that would miss all Midtown hotels.

On this plan, the need to link the new elements to the Third Avenue trunk leads to incoherent lines. High-frequency east-west trunks would make a lot of sense, complementing the north-south trunk, but instead of connecting Hoboken with Brooklyn and 57th Street with Long Island, both end up hooking to the north-south trunk and loop back to connect to each other. The proposed tunnels are already there, in the form of Gateway East and the trunk connection to Brooklyn, they just don’t align. Instead, the only east-west alignment that fully goes through is Gateway, with just one stop in Manhattan at Penn Station, except in the tunnel that also has an additional stop at off-Midtown 31st and 3rd.

4. Harlem Line Tunnel

Between Grand Central and Wakefield, the Harlem Line has four tracks. In the South Bronx, the Hudson Line splits off, but the rest of the Harlem Line still has four tracks. Thus, the Bronx effectively has six tracks feeding four in Manhattan. It is this configuration that probably led the RPA to believe, in error, that two additional regional rail tracks in Manhattan were required. In this situation, it is unlikely there will ever be capacity problems on the Harlem Line in the Bronx – the bottleneck is further south. So why is the RPA proposing to add two more tracks to the Harlem Line, in a tunnel?

In section 1 of this post, I defined the Third Avenue trunk’s unnecessary part as running from Grand Central to 138th Street, a total of 8 km. This tunnel, from 138th to the depicted northern end at Woodlawn, where the Harlem and New Haven Lines split, is 11 km. In a city with reasonable cost control, this should be around $2.5 billion. In New York, it would be much more – I can’t tell how much, since it is likely to be cheaper than the recent subway projects (Second Avenue Subway Phase 1, and the 7 extension), both of which were in Manhattan, but I would guess about $10 billion is in line with existing New York costs. Is there any valid reason to spend so much money on this tunnel?

When I interviewed Tom Wright and Foster Nichols for my above-linked Streetsblog piece, I only saw the plans around Gateway, and was aware of the Third Avenue trunk idea but not of any of the details, so I never got a chance to ask about the Harlem Line express tunnel. So I can only guess at why the RPA would propose such a line: it got some pushback from the suburbs about wanting more express trains. The RPA could try to explain to suburbanites that the new system would not be so slow in the Grand Central throat: Metro-North does the 6.6 km from 125th to Grand Central in 10 minutes; the trains are capable of doing it in 5-6 minutes, but the last 15 blocks are excruciatingly slow, which slowness would be eliminated with any through-running, via the existing tunnels or via Third Avenue. Instead, for the same reason the organization caved to Long Island pressure to include Gateway East, it caved to Westchester pressure to include more express tracks.

In reality, this tunnel has no merit at all. The way the existing suburban lines are laid out points to a clear service pattern: the Harlem Line on the local tracks, the New Haven Line on the express tracks (regardless if those trains run local or express on the New Haven Line farther out). Wakefield has four tracks and two platforms, but the Harlem and New Haven Lines split just short of it; perhaps new local platforms on the New Haven Line could connect to it, or perhaps the junction could be rebuild north of Wakefield, to enable transfers. With much of the New Haven Line capacity occupied by the reverse-branch to Penn Station Access, there wouldn’t be much of a capacity crunch on the express tracks; in a counterfactual in which reverse-branching is not a problem, some Harlem Line trains could even be routed onto the spare capacity on the express tracks.

Build a Network, Not One Line With Branches

In the short run, the biggest thing the RPA is proposing for regional rail in New York is Gateway plus tie-ins. But this doesn’t really distinguish it from what the politicians want. The real centerpiece of the Fourth Plan, as far as regional rail goes, is the Third Avenue trunk line – even taking over some functionality of Second Avenue Subway, which the RPA proposes to not build south of 63rd Street.

Unfortunately, this trunk line, while almost good, doesn’t quite work. It has 19 km of superfluous tunneling, from Grand Central to Woodlawn, adding no new service to the system, nor new connections to existing service, nor more capacity on lines that really need it. And it insists on linking new east-west tunnels beyond Gateway to the same trunk, ensuring that they couldn’t really work as east-west trunks from New Jersey to Brooklyn, Queens, and Long Island. In centering the trunk, the RPA is in effect ruining the possibility for additional trunks creating a bigger system.

Building a north-south trunk leveraging the Harlem Line is a no-brainer. When I sent Yonah Freemark my first regional rail proposal in 2009, he responded with some draft he’d been working on, I think as an RPA intern, proposing a through-running network using the Harlem Line, with an extension to the south with an onward connection to Brooklyn much like the RPA’s current Third Avenue trunk south of 42nd Street. It’s something that different people with an interest in improving New York’s transit system could come up with independently. What matters is the details, and here, the Fourth Regional Plan falls short.

Agency Turf Battles and Construction Costs

This is a touched-up version of an article I tried publishing earlier this year, changed to be more relevant to regular blog readers, who know e.g. what Gateway is.

I’ve talked a lot about high rail construction costs in the US, especially in New York: see here for a master list of posts giving cost figures, and here and here for posts about things that I do not think are major reasons. In this post, I’d like to talk about one thing that I do think is relevant, but not for every project: agency turf battles.

The German/Swiss planning slogan, organization before electronics before concrete, means that transit agencies should first make sure all modes of public transit are coordinated to work together (organization) before engaging in expensive capital construction. In the US, most urban transit agencies do this reasonably well, with integrated planning between buses and trains (light rail or subway); there’s a lot of room for improvement, but basics like “don’t run buses that duplicate a subway line” and “let people take both buses and subways on one ticket” are for the most part done. Readers from the San Francisco Bay Area will object to this characterization, but you guys are the exception; New York in contrast is pretty good; Chicago, Boston, and Philadelphia are decent; and newer cities run the gamut, with Seattle’s bus reorganization for its light rail being especially good.

But then there’s mainline rail, with too many conflicting agencies and traditions. There is no place in the US that has commuter rail and successfully avoids agency turf battles, even regions where the integration of all other modes is quite good, such as New York and Boston. I have complained about this in Philadelphia, and more recently criticized the RPA’s Fourth Regional Plan for letting Long Island claim the East River Tunnels as its own fief.

But all of this pales compared with what is actually going on with the Gateway tunnel. The New York region’s political leaders have demanded funding for a $25 billion rail tunnel between New York Penn Station and New Jersey. When Donald Trump had just won the election, Schumer proposed Gateway as a project on which he could cooperate with the new president; Booker got some federal money earlier, in the Obama administration.

The circumstances leading to the Gateway announcement are themselves steeped in inter-agency intrigue. Gateway is the successor to an older scheme to build a rail tunnel under the Hudson, called ARC. In 2010, Chris Christie acquired some notoriety for canceling it as construction started.

Earlier, in 2003, Port Authority studied three ARC alternatives. Alt P would just serve Penn Station with a new cavern adding more terminal tracks; Alt G would serve Penn Station and build a new tunnel connecting to Grand Central; Alt S would serve Penn Station and build a new tunnel to Long Island, at Sunnyside. The three options each cost about $3 billion, but Alt G had the highest projected ridership. Alt G had the opportunity to unite New Jersey Transit’s operations with those of Metro-North. Instead, Alt P was chosen, and the cavern was involved in the cost escalations that led Christie to cancel the project, saying the then-current budget of $9 billion would run over to $12.5 billion.

It is hard to say why Port Authority originally chose Alt P over Alt G. Stephen Smith spent years sending freedom of information requests to the relevant agencies, but never received the full study. Agency turf battles between New Jersey Transit and Metro-North are not certain, but likely to be the reason.

I talked to Foster Nichols a few months ago, while researching my Streetsblog piece criticizing the RPA plan for kowtowing to Long Island’s political demands too much. Nichols oversaw the reconstruction of Penn Station’s LIRR turf in the 1990s, which added corridors for passenger circulation and access points to the tracks used by the LIRR; he subsequently consulted on the RPA plan for Penn Station. Nichols himself supports the current Gateway plan, which includes the $7 billion Penn Station South complex, but he admitted to me that it is not necessary, just useful for simplifying planning. The Pennsylvania Railroad designed Penn Station with provisions for a third tunnel going east under 31st Street, which Alts S and G would leverage; Alts S and G are still possible. The one caveat is that the construction of Sixth Avenue Subway, decades after Penn Station opened, may constrain the tunnel profile – the ARC documents assumed locomotive-friendly 2% grades, but with EMU-friendly 4% grades it’s certainly possible.

With this background, I believe Alt G was certainly feasible in the mid-2000s, and is still feasible today. This is why I keep pushing it in all of my plans. It’s also why I suspect that the reason Port Authority decided not to build Alt G was political: the hard numbers in the study, and the background that I got from Nichols, portray Alt G as superior to Alt P. The one complaint Nichols had, track capacity, misses the mark in one crucial way: the limiting factor is dwell times at Penn Station’s narrow platforms, and having two Midtown stations (Penn Station and Grand Central) would allow trains to dwell much less time, so if anything capacity should be higher than under any alternative in which trains only serve one of the two.

The upshot is that Christie had legitimate criticism of ARC; he just chose to cancel it instead of managing it better, which Aaron Renn called the Chainsaw Al school of government. After Christie canceled ARC, Amtrak stepped in, creating today’s Gateway project. Even without the cavern, Gateway’s estimate, $13.5 billion in 2011, was already higher than when Christie canceled ARC; it has since risen, and the highest estimate I’ve seen (by Metro, so caveat emptor) is $29 billion. This includes superfluous scope like Penn South, which at one point was supposed to cost $6 billion, but more recently Nichols told me it would be $7 billion.

While bare tunnels would provide the additional capacity required at lower cost, they would require interagency cooperation. Amtrak, New Jersey Transit, and the LIRR would need to integrate schedules and operations. Some trains from New Jersey Transit might run through to the east as LIRR trains and vice versa. This would make it easier to fit traffic within the existing station, and only add bare tunnels; the Penn Station-Grand Central section, at the southern end of the station, would keep dwell times down by having two Midtown stations, and the section connecting New Jersey Transit with Long Island (probably just Penn Station Access and one LIRR branch, probably the Port Washington Branch) would have 8 station tracks to play with, making dwell times less relevant. Unfortunately, this solution requires agencies to share turf, which they won’t – even the Penn Station concourses today are divided between Amtrak, New Jersey Transit, and LIRR zones.

Gateway is not the only rail project suffering from cost blowouts; it is merely the largest. The LIRR is building East Side Access (ESA), to connect to Grand Central; right now, it only serves Penn Station. ESA uses an underwater tunnel built in the 1960s and 70s to get to Manhattan, and is now boring a 2 km tunnel to Grand Central, at a cost of $10 billion, by far the most expensive rail tunnel in the world per unit length. But the tunnel itself is not the biggest cost driver. Instead of having the LIRR and Metro-North share tracks, ESA includes a deep cavern underneath Grand Central for the LIRR’s sole use, similar to the one in ARC that Christie canceled. About $2 billion of the cost of ESA is attributed to the cavern alone.

Agency turf wars are not unique to New York. In California, the same problem is driving up the costs of California HSR. In inflation-adjusted dollars, the project’s cost has risen from $33 billion in 2008 to $53 billion today. Most of the overrun is because the project includes more tunnels and viaducts today than it did in 2008. Much of that, in turn, is due to conflicts between different agencies, especially in the San Francisco Bay Area. The worst example is San Jose Diridon Station.

Diridon Station is named after still-living former California HSR Authority board member Rod Diridon, previously responsible for the disaster that is VTA Light Rail, setting nationwide records for low ridership and poor cost recovery. The station’s main user today is Caltrain. California HSR is planned to serve it on its way between Los Angeles and San Francisco, while Caltrain and smaller users plan to grow, each using its own turf at the station. The planned expansion of track capacity and new viaducts for high-speed rail is estimated to cost about a billion dollars. Clem Tillier calls it “Diridon Pan-galactic” and notes ways this billion-dollar cost could be eliminated, if the users of the stations shared turfs. Clem identifies $2.7 billion in potential savings in the Bay Area through better cooperation between high-speed rail, Caltrain, and other transit systems.

It is not a coincidence that the worst offenders – Gateway, East Side Access, and California High-Speed Rail – involve mainline rail. American and Canadian passenger railroads tend to be technologically and managerially conservative. Most still involve conductors punching commuter tickets as they did in the 1930s; for my NYU presentation, I found this picture from 1934.

I suspect that this comes from a Make Railroading Great Again attitude. Old-time railroaders intimately understand the decline of mainline rail in the United States in the middle third of the 20th century, turning giants like the Pennsylvania Railroad into bankrupt firms in need of federal bailouts. This means that they think that what needs to be done is in line with what the railroads wanted in the 1920s, 30s, 40s, and 50s. Back then, people lived in the suburbs and commuted downtown at rush hour, so there was no need for intra-suburban service, for in-city stops (those were for working- and middle-class city residents, not rich suburbanites in Westchester), or for high off-peak frequency. There was no need for cooperation between different railroads then, since commuters would rarely need to make an onward connection, which led to a culture encouraging competition over cooperation.

Among all the explanations for high construction costs, turf battles is the single most optimistic. But Americans should be optimistic about building cost-effective passenger rail. If this is the main culprit – and it is in the Bay Area, and one of several big culprits in New York – then all it takes to fix the cost problem is bringing organizational practices to the 21st century, which is cheap. It is too late for East Side Access, but it is possible to drastically reduce the cost of Gateway by removing unnecessary items such as Penn Station South. This can be repeated for smaller projects in the San Francisco Bay Area and everywhere in the US where two separate transit agencies fight over station space.

Am I optimistic that Americans will actually do this? I am not. Even outfits that should know better (again, the RPA) seem too conservative and too politically constrained; the RPA is proposing systemwide integration in its Fourth Plan, but in a way that incorporates each player’s wishlist rather than in a way that uses integration to reduce capital investment needs. In California, the HSR Authority seems to be responding to demands for value engineering by procrastinating difficult decisions, and it comes down to whether in the moment of truth it will have politicians in the state and federal governments who are willing to pay billions of dollars of extra money.

However, I do think that a few places might be interested in running public transit better. Americans are not incorrigible, and can learn to adapt best industry practices from other countries, given enough pressure. From time to time, there is enough pressure, it’s just not consistent enough to ensure the entire country (or at least the most important transit cities, led by New York) modernizes.

The RPA’s Fourth Regional Plan

The RPA has just put up its Fourth Regional Plan, recommending many new subway and commuter rail lines in New York, ranging from good (125th Street subway, Brooklyn-Lower Manhattan regional rail) to terrible (Astoria Line extension to the west rather than to LaGuardia, which gets a people mover heading away from Manhattan). I have a poll for Patreon supporters for which aspects I should blog about; I expect to also pitch some other aspects – almost certainly not what I said in my poll – to media outlets. If you support me now you can participate in the poll (and if you give $5 or more you can see some good writings that ended up not getting published). If you want to be sneaky you can wait a day and then you’ll only be charged in January. But you shouldn’t be sneaky and you should pledge today and get charged tomorrow, in December.

It’s hard to really analyze the plan in one piece. It’s a long plan with many components, and the problems with it don’t really tell a coherent story. One coherent story is that the RPA seems to love incorporating existing political priorities into its plan, even if those priorities are bad: thus, it has the AirTrain LaGuardia, favored by Cuomo, and the Brooklyn-Queens Connector (BQX), favored by de Blasio, and even has tie-ins to these plans that don’t make sense otherwise. Some of the regional rail money wasters, such as Penn Station South and the new East River tunnels from Penn Station to the LIRR, come from this story (the LIRR is opposed to any Metro-North trains going to Penn Station under the belief that all slots from points east to Penn Station belong to Long Island by right). However, there remain so many big question marks in the plan that are not about this particular story that it’s hard to make one criticism. I could probably write 20,000 words about my reaction to the plan, which is about 15 published articles, and there are, charitably, 5 editors who will buy it, and I’m unlikely to write 10 posts.

I’ll wait to see how the poll on Patreon goes, and what editors may be interested in. There are interesting things to say about the plan – not all negative – in areas including rail extensions, transit-oriented development, and livable streets. But for now, I just want to zoom in on the crayon aspects. I previously put up my 5-line map (4 MB version, 44 MB version). The RPA proposal includes more tunnels, for future-proofing, and is perhaps comparable to a 7-line map I’ve been working on (4 MB version, 44 MB version):

I was mildly embarrassed by how much crayon I was proposing, which is why what I put in my NYU presentation 3 weeks ago was the 5-line system, where Line 1 (red) is the Northeast Corridor and the Port Washington Branch, Line 2 (green) is much the same but through the new Hudson tunnels, Line 3 (orange) is the Empire Connection and the Hempstead Branch, Line 4 (blue) connects the Harlem Line and Staten Island, Line 5 (dark yellow) connects the Erie Lines with the Atlantic Branch and Babylon Branch, and Line 6 (purple) is just East Side Access. In the 7-line system, Line 6 gets extended to Hoboken and takes over the Morris and Essex Lines, and Line 7 (turquoise) connects the Montauk Line with the Northern Branch and West Shore Line via 43rd Street, to prune some of the Line 5 branches.

With all this extra tunneling, the map has 46 new double-track-km of tunnel. With just Lines 1-5, it has 30; these figures include Gateway and the other tunnels highlighted in yellow (but not the highlighted at-grade lines, like Lower Montauk), but exclude East Side Access. In contrast, here’s what the RPA is proposing:

Counting the Triboro-Staten Island tunnel and Gateway starting from the portal (not at Secaucus as the map portrays), this is 58 route-km, and about 62 double-track-km of tunnel (the Third Avenue trunk line needs four tracks between 57th and Houston at a minimum), for substantially the same capacity. The difference is that the RPA thinks Metro-North needs two more tracks’ worth of capacity between Grand Central and 125th, plus another two-track tunnel in the Bronx; from Grand Central to Woodlawn, the Fourth Regional Plan has 19 km, slightly more than 100% of the difference between its tunnel length and mine. My plan has more underwater tunnel, courtesy of the tunnel to Staten Island, but conversely less complex junctions in Manhattan, and much more austere stations (i.e. no Penn Station South).

As I said, I don’t want to go into too much detail about what the RPA is doing, because that’s going to be a series of blog posts, most likely a series of Streetsblog posts, and possibly some pieces elsewhere. But I do want to draw a contrast between what the RPA wants for regional rail and what I want, because there are a lot of similarities (e.g. look at the infill on the Port Washington Branch in both plans), but some subtle differences.

What I look for when I think of regional rail map is an express subway. I’ve been involved in a volunteer effort to produce a regional rail plan for Boston, with TransitMatters, in which we start by saying that our plan could be a second subway for Boston. In New York, what’s needed is the same, just scaled up for the city’s greater size and complexity. This means that it’s critical to ensure that the decision of which lines go where is, for lack of a better word, coherent. There should be a north-south line, such as the Third Avenue trunk in the Fourth Regional Plan or my Line 4; there should be an east-west line, such as the lines inherited from the legacy Northeast Corridor and LIRR; and so on.

The one big incoherence in my plan is the lack of a transfer station between Line 4/6 and Line 1/3 at Madison and 33rd. This is on purpose. Line 2 connects Penn Station and Grand Central, Madison/33rd is well to the south of Midtown’s peak job density, and Lines 4 and 6 shouldn’t be making more stops than the 4 and 5 subway lines, which go nonstop between Grand Central and Union Square.

The other weirdness is that in the 7-line system, unlike the 5-line system, there is no way to get between the Northern Branch or the West Shore Line and the rest of New Jersey without going through Manhattan. In the first map of this system that I made on my computer, Line 7 has an awkward dip to serve the same Bergenline Avenue station as Line 2. But I think what I posted here, with two separate stations, is correct: Lines 6 and 7 are lower priorities than a subway under Bergenline Avenue, which would make intra-state connections much easier. It’s difficult to depict rail extensions at different scales on one geographically accurate map, and doing a schematic map like the London Underground isn’t useful for depicting new lines, which should make it clear to readers where they go. But the 7-line system must be accompanied by subway extensions, some covered by the RPA (Utica, Nostrand) and some not (Bergenline, again).

I recently had to give a short description of my program for good transit, and explained it as, all aspects of planning should be integrated: operations and capital planning, buses and light rail and subways and regional rail, infrastructure and rolling stock and scheduling, transit provision and development. When I make proposals for regional rail, they may look out there, but the assumption is always that there’s a single list of priorities; the reason I depict a 7-line map, or even a 9-line map (in progress!), is to be able to plan lines 1-3 optimally. Everything should work together, and if agencies refuse to do so, the best investment is to make sure those agencies make peace and cooperate. The RPA plan sometimes does that (it does propose some regional rail integration), but sometimes it’s a smörgåsbord of different politically-supported proposals, not all of which work together well.

Suburban Transit-Oriented Development

Here’s a Google Maps image of Southport, a section of Fairfield, Connecticut with its own Metro-North commuter rail station:

Here’s an image at the same scale of Bourg-la-Reine, an inner suburb of Paris on the RER B, at the junction between the line’s two southern branches:

At Bourg-la-Reine, the buildings just east of the station are high-rise. There are local community amenities, including walkable schools, supermarkets, and pharmacies, and people can comfortably live in this suburb without a car. This generates significant RER traffic at all hours of day: outbound trains are often standing-room only until they reach this station even in midday, outside rush hour.

At Southport, there are a few townhouses near the station. But the roads are wide and hostile to pedestrians, and the nearest supermarket closes at 6 pm, too late for commuters returning from the city. Car ownership approaches 100%, and nobody rides the trains except to get to office jobs at the traditional peak hour in Manhattan (or perhaps Stamford).

The difference between the two places is so stark that they can barely be compared. Southport has 317 inbound boardings per weekday. Of those, 263, or 83%, are in the morning rush hour; the Metro-North-wide average is 63%, and the average on the SNCF-operated parts of the RER and Transilien is about 46%. Bourg-la-Reine has 4.5 million annual riders, about 16,000 on an ordinary working day.

A huge part of the difference is about service provision – Bourg-la-Reine has a train every five minutes midday, Southport a train every hour. But it’s not just about service. The RER has stations farther out, with somewhat less intense service, such as a train every 15 minutes, with comparable ridership. And the LIRR and Metro-North have little off-peak ridership even at stations with more frequent service, such as Mineola and Hicksville. Transit-oriented development (TOD) is as important as good service in such cases.

I bring up Southport because the RPA just dropped a study about suburban TOD that grades every New York commuter rail station between 0 and 3, and gives Southport the highest mark, 3. The RPA study looks at zoning within 800 meters of each station and considers whether there’s a parcel of land that permits multifamily housing with a floor are ratio higher than 1.25. Southport has such lots, supporting some townhouses, so according to the RPA it gets full marks, even though, by RER standards, it is like every other American car-oriented suburb.

Based on this methodology, the RPA identifies a number of good suburbs, and even comes to policy conclusions. It proposes more TOD in the mold of existing exurban New York examples, such as Patchogue. The model for the program is the real reason the RPA study is so weak: rather than calling into attention the big differences between land use at suburban stations in New York versus in Paris (or any number of big European cities with suburban rapid transit), it overfocuses on small differences within auto-oriented suburbia.

Some of the ultimate conclusions are not terrible. For example, the RPA is proposing linking federal infrastructure development to permitting more multifamily housing. This would improve things. However, the problem with this is twofold. First, it is unrealistic – the federal government gave up decades ago on enforcing fair housing laws, and has no interest in attempting to make exclusionary suburbs behave. Were I to propose this, hordes of American commenters would yell at me for not understanding American politics. And second, it misunderstands the nature of the problem, and ends up proposing something that, while unrealistic, is still low-impact.

The best way to understand the problem with the study is what author Moses Gates told me on Twitter when I started attacking it. He said that the RPA was looking at zoning rather than actual development. Since there is zoning permitting multifamily development within the prescribed radius at Southport, it gets full marks. With my understanding of what good TOD looks like, I would be able to say that this is clearly so bad the methodology must be changed; on Twitter I suggested looking at zoning within 300 meters of the station rather than 800, since the highest-intensity development should be right next to the station. I also suggested looking at supportive nonresidential uses, especially supermarkets. A development that isn’t walkable to retail at reasonable hours is not TOD.

The RPA does not think in this language. It thinks in terms of internal differences within the US. Occasionally it deigns to learn from London, but London’s suburban development is auto-oriented by European standards (transit mode share in the London commuter belt is at best in the teens, often in the single digits). Learning from anywhere else in the world, especially places that don’t speak English, is too difficult. This means that the RPA could not reach the correct conclusion, namely, that there is no such thing as an American suburb with TOD. The only exception I can come up with in the United States involves Arlington, on the Washington Metro, and Arlington is no longer considered a suburb, but really a full-fledged city in a different state, like Jersey City.

The other thing the RPA missed is that it drew too large a radius. TOD at a train station should include townhouses 800 meters out – but it’s more important to include high-rise residential construction next to the train station and mid-rise apartment buildings 500 meters out. Giving American suburbs latitude to place TOD so far from the station means they will act like Southport and allow small amounts of multifamily housing out of the way, while surrounding the station itself with parking, a tennis court, and large single-family houses with private swimming pools. This is not hypothetical: suburbs in New Jersey have reacted to court rulings mandating affordable housing by permitting apartments at the edge of town, far from supporting retail and jobs, and keeping the town core single-family.

Because the RPA missed the vast differences in outcomes between the US and France, it missed some useful lessons:

  • States should centralize land use decisionmaking rather than give every small suburb full autonomy.
  • TOD doesn’t need to be fully mixed-use, but there should be some local retail right next to housing.
  • Housing should be high-density right next to the station. A floor area ratio of 1.25 is not enough.
  • Publicly-funded social housing should be next to train stations, in the city as well as in the suburbs, and this is especially important in expensive suburbs, which aren’t building enough affordable housing.

Without suburban TOD, any regional rail system is incomplete. I wish I could have covered it at my talk, but I didn’t have time. Good service needs to run to dense suburbs, or at least suburbs with dense development within walking distance of the station. It needs to extend the transit city deep into suburbia, rather than using peak-only commuter rail to extend the auto-oriented suburbs into the city.

I Gave a Talk About Regional Rail

I expect there will be writeups about the talk (e.g. on Streetsblog). But meanwhile, here are my slides (warning: 17 MB, because of pictures). These are identical to what was shown at the talk, with two differences: I fixed one small mistake (Fordham Road vs. Pelham Parkway), and I consolidated the pauses, so each slide is a page, rather than a few pages, each page adding a line.

There were light fantasy maps in the talk. Because of size, I’m not embedding them in the post. But there are links:

Yellow highlights around a line indicate it’s new; Gateway is highlighted in one direction since it’s an existing two-track line to be four-tracked. On the infill map, solid circles are existing stations, gray circles are planned stations, white circles are my suggestions for additional infill.

There’s More Redundancy Than You Think

I was visiting Boston last week, and am in New York this week; you can see me at NYU on Thursday tomorrow. Last week, I met with TransitMatters activists talking about bus and rail improvements in Boston, and on the way saw something that made me understand two things. First, the MBTA is run by incompetent people. And second, even two subway lines that are perpendicular and serve completely different areas can be redundant with each other.

Two and a half years ago, I said redundancy is overrated. In this post, I’d like to argue from the opposite direction: transit networks have more redundancy than they appear to. One implication is identical to that of my older post: transit agencies should build subway lines without regard for redundant service, since not only is redundancy overrated, but also a new subway line is redundant with old lines even if they serve completely different areas. But the other implication concerns service interruptions and shutdowns.

The issue in Boston is that, although there are nighttime shutdowns, there are also occasional weekend shutdowns, as in New York, for major capital projects. The Red Line is being closed on weekends for two months on the segment between Boston proper and Cambridge. But the Orange Line is also being closed on weekends on segments, after deferred maintenance led to a meltdown in the last two months, with frequent delays and slow zones. Last weekend, I found myself having to go between Davis Square (on the Red Line, just off the edge of the map) and Jamaica Plain (near the bottom of the Orange Line) to visit Sandy Johnston, with the highlit segments shut down:

Shuttle buses replaced the subway on both segments. On the Red Line, the MBTA contracted it out to a private company that used wheelchair-inaccessible high-floor buses; there were not enough MBTA bus drivers to run the shuttles on both segments, and by union rules the MBTA could not use contract drivers on its own buses even though it did have the equipment, forcing it to use inferior private-sector buses. I am able-bodied enough to climb high-floor buses, but I would not use the shuttle buses replacing the Red Line for another reason: as can be seen in the map, there is no continuous street grid between Charles/MGH and Park Street. If there were a crossover right east of Charles/MGH then only the Kendall-MGH segment would be bustituted, and there, the buses would go on Longfellow Bridge, with a serious but not fatal slowdown. But between Kendall and Park Street the buses have to swerve through side streets that were not designed for fast traffic; in 2012, I was on such a shuttle and as I recall the trip took 15 or 20 minutes, where the subway does it in about 5.

Instead of relying on shuttles, I took a bus north of the river to get to Lechmere and use the Green Line to reach Chinatown on a chain trip. From Chinatown the options were all bad, and I rode the 39 bus, which parallels the Green Line E Branch (the southernmost one) and continues south to Forest Hills, where the Green Line once ran as well. The way back was not a chain trip, and with a bus-bus-Red Line trip and no 39 bus in sight (the online bus tracker was down), I gave up and took a taxi.

The Red Line and Orange Line look like they go in different directions, so shutting down one does not affect the other. But in reality, in a city with buses, taking the bus to a different line is a common strategy to deal with shutdowns – hence, using the Green Line to get between Davis and Chinatown, taking a bus in a place where the buses are less slow than between Charles/MGH and Park Street.

If any city in North America did not use buses at all, it would be Boston. It has legendarily narrow and twisted streets, and crawling buses. It has higher rail-to-bus ridership ratio than any other American city except possibly New York, and far higher ratio than the major English Canadian cities with their bus grids. Its transit network, inherited from midcentury, uses the buses to feed the subway, and has no bus service through downtown, where even before mass motorization there were traffic jams of streetcars.

But even in Boston, using the bus outside the core to get to a better subway line is possible, and normal when there are service interruptions. This means that any pair of subway lines could potentially be redundant with each other. This means that it is bad practice to shut down more than one line at once for repairs. The reason the Orange Line needs emergency repairs in the first place is that the MBTA maintained it poorly and wouldn’t act when it was less urgent, such as six months ago (Sandy reports noticing a consistent deterioration in service since January). Today, the shutdowns are probably unavoidable. But the Red Line shutdowns, for a capital construction project involving the Longfellow Bridge, can be delayed. The MBTA should do that in the future in order to both avoid having to use inaccessible buses and allow passengers to take a circumferential bus to a functioning subway line.

Fix DeKalb Avenue

In New York, there are two dedicated subway tracks on the Manhattan Bridge offering a bypass of Lower Manhattan. Between DeKalb Avenue in Brooklyn and Canal Street in Chinatown in Manhattan, Q trains run nonstop for 3.5 km, while the R train goes the long way, taking 5.5 km and making 2 intermediate stops in Downtown Brooklyn and 4 in Lower Manhattan. The N skips DeKalb Avenue, with a 4.5 km nonstop segment between Canal Street and the Atlantic/Pacific/Barclays station complex.

The Q and N should be immense time savers. Instead, the Q does the trip in 8 minutes and the N in 10, both of which average 26-27 km/h. The subway’s overall average speed, weighed down by local trains stopping every 700 meters, is 29 km/h. The Q and N are still time savers, though, because the R does the 5.5 km in 18 minutes, an average speed of 16 km/h – far less than the systemwide average, and even less than the slowest Paris Metro line, Line 4 with its 500-meter interstations and 20 km/h average speed. Between DeKalb and Pacific, about 800 meters, the R takes 3 minutes. Unfortunately, New York City Transit is not taking any measures that would fix this, and when I asked about one possibility, I got excuses.

There are two reasons why this part of the subway is so slow. The first is something called signal timers. Timers are devices installed at frequent intervals on long interstations, such as the bridges and tunnels connecting Manhattan with Brooklyn and Queens, limiting train speed. These timers have always been around, but after fatal accidents in the 1990s, New York City Transit tightened them, reducing speed further; for some more background, see my Vox piece from last summer. The timers are more safety theater than safety. The biggest conclusion I reached from looking at the accident postmortem on the NTSB and some NYCT information was “make sure your trains’ brakes work as intended”; NYCT derated the trains’ service and emergency braking rates later in the 90s, which marginally reduces maintenance costs but is bad for safety and brutal for train speed.

The second reason is the switches at DeKalb Avenue. DeKalb is a six-track station, with four tracks feeding the Manhattan Bridge and two feeding the tunnel through Lower Manhattan. The two tunnel tracks then continue to the south as local tracks on the Fourth Avenue Line, carrying the R; this is the least used of all subway trunk lines into Manhattan, because the detour and low speed make it useless for most Midtown-bound passengers. The four bridge tracks include two express tracks at DeKalb going to the Brighton Line, and two super-express tracks skipping DeKalb continuing to the south as express Fourth Avenue tracks. Today, there is a splitting and recombining of branches. The B and D run together from Sixth Avenue to the Manhattan Bridge, and the N and Q run together from Broadway, but just north of DeKalb they recombine as B and Q running to Brighton, and D and N running super-express down Fourth Avenue.

This recombination at DeKalb slows down trains considerably, in two ways. First, the interlocking is complex. You can see it on this map on NYCSubway.org; in addition to splitting and recombining the B, D, N, and Q, it also has a non-revenue connection allowing R trains to serve the Brighton Line. Trains on diverging turnouts go at glacial speeds. And second, trains from four lines influence one another’s schedules, and delays propagate. Supervising train movements is thus difficult, and control center has to have a camera watching the trains enter the interlocking to ensure they adhere to schedule; timetables have to take the resulting delays into account.

When I first complained about reverse-branching in New York, I talked about capacity limits imposed by having more trunk lines than branches, a situation that is still to some extent true going north and east of Midtown. At DeKalb, there are six tracks going in and six going out, but the recombination makes things slower, and should be removed. NYCT should make a decision between having B and D trains run on the Brighton Line and the N and Q on Fourth Avenue, or the reverse. The interlocking permits either option, with entirely grade-separated junctions, allowing the trains on the two lines to no longer interfere with each other’s operations.

I in fact asked NYCT about it by proxy. NYCT dismissed the idea, on the grounds that transfer volumes between the B/D and N/Q would be too big. At Atlantic/Pacific, the Pacific side has a cross-platform transfer between the local R and express D/N, but going between the Pacific side and the Atlantic side (the B/Q, and separately the 2/3/4/5) involves a lot of walking. NYCT believes that passengers would flood the corridors looking for a train to their preferred destination, and the transfer volumes would require trains to have long dwell times. NYCT said nothing about whether the overall speed would actually fall, but I believe that based on the large transfer volumes NYCT predicts, passenger trip times (including transfer times) would rise. The only problem: I don’t believe NYCT’s prediction is true at all.

The B and D trains go express up Sixth Avenue, making stops at Grand Street in Chinatown, Broadway-Lafayette on Houston Street, West Fourth Street in the Village, and Herald Square. The N and Q trains go express up Broadway, serving Canal Street in Chinatown, Union Square, and Herald Square. North of Herald Square the two lines are never more than one long block apart until they leave Midtown. Passengers going toward Midtown are unlikely to have strong opinions about which of the two lines they would prefer.

Passengers going to destinations between Manhattan Bridge and Midtown might register stronger preferences. Union Square is the fourth busiest subway station in New York, and is quite far from the B and D. The closest alternative using the B and D is to change cross-platform to the M or F at West Fourth, and get off at 14th Street and Sixth Avenue, two long blocks from Union Square. Three more stations are potential concerns: Canal Street ranks 18th, West Fourth ranks 21st, and Broadway-Lafayette ranks 25th. Getting to Broadway-Lafayette from the N or Q is easy: the station and Canal Street are both on the 6, and passengers can transfer to the 6 at Canal.

West Fourth and Canal remain concerns, but they are not huge ones; they are secondary destinations. Canal is only a major destination for Chinese-New Yorkers, and in Brooklyn they cluster in Sunset Park along Fourth Avenue, suggesting that the Fourth Avenue express tracks should carry the N and Q and the Brighton tracks should carry the B and D. The urban geography of Chinese-New Yorkers is changing due to the combination of fast immigration and fast integration and migration to the suburbs, but this is a service decision, not an infrastructure investment; it can be reversed if demographics change.

Moreover, as a destination, West Fourth is predominantly used for NYU. The Village is a dense residential neighborhood, and West Fourth allows its residents to easily reach Lower Manhattan, Downtown Brooklyn, and two different four-track trunk lines through Midtown. But it has few jobs, outside NYU, which lies mostly between Sixth Avenue and Broadway. Union Square can adequately serve people going toward NYU, and stations on the R and 6 to the south can serve people going to NYU even better. The one problem is that the transfer between the R and the N/Q at Canal Street is not cross-platform; the cross-platform transfers start at Union Square. But with coverage of multiple stations walkable to NYU, the loss of the one-seat ride to West Fourth is not fatal. Even the transfer to the A, C, and E trains at West Fourth has alternative options: passengers from the N or Q going to the E can transfer to the F or M at Herald Square and reach the same stations, and passengers going to the A or C can transfer to the 1 at Times Square and to the A or C at Columbus Circle, both of which transfers are not much harder than climbing two flights of stairs at West Fourth.

With so many options, not many riders would be connecting at Atlantic/Pacific, and trains could keep dwell times short. If anything, dwell times might be shorter, because missing a train would be less fatal: the next train on the same track would serve the same destinations in Midtown, so riders would only need to wait about 3 minutes at rush hour, and 5 minutes off-peak. The gain in speed would be substantial, with the interlocking imposing fewer operational constraints.

NYCT might need to slightly rework the switches, to make sure the chosen matching of the lines in Manhattan and Brooklyn takes the straight and not the diverging direction at the turnouts; typically, the straight direction imposes no speed limit (up to full line speed on high-speed rail lines), but the diverging direction is slow. A matching in which the B and D go on Brighton and the N and Q on Fourth Avenue express to my understanding already involves only one diverging move, if I am reading the track map linked on NYCSubway.org correctly. At the same time, NYCT could fix the switches leading to the R: there was through-service from the Brighton Line to the tunnel tracks the R uses today, but there no longer is, so this out-of-service connection should get diverging and not straight moves. But even with the R, the capital investment involved is minimal.

I do not know the potential travel time gains between DeKalb and Canal Street (or Grand Street) with no timers or reverse-branching. With straight tracks across Manhattan Bridge, and wide curves toward Grand Street, 3.5-minute trips are aspirational, 4-minute trips are still possible, and 5-minute trips should be easy. From Pacific Street, add one more minute, corresponding to cruising at 50 km/h, a speed limit the subway routinely attains even on local tracks. This saves passengers from DeKalb about 4 minutes, and passengers from Pacific about 5. The average trip across the system is about 21 minutes, and the average delay (“excess journey time“) is 3 minutes. The saving would be immense, and contribute to both more casual ridership between Brooklyn and Manhattan, and lower operating costs coming from faster trips.

NYCT should not make excuses for this. The timers may have been originally justified as a safety improvement, but reducing train braking rates had the opposite effect. And, uniquely among the various reverse-branch points in New York, DeKalb feeds two Manhattan trunks that are very close to each other, especially in Midtown, to the point that one-seat rides to every stop have limited value. It should make a decision about whether to run the B/D together on Fourth Avenue and the N/Q on Brighton (switching the Q and D) or the reverse (switching the B and N), based on origin-and-destination data. Some passengers might bemoan the loss of one-seat rides, but most would cheer seeing their trips sped up by 4-5 minutes.

Little Things That Matter: Vertical Circulation

Chatelet-Les Halles has a problem with passenger circulation. It has exceedingly wide platforms – the main platforms, used by the RER A and B, are 17 meters wide – but getting between the platform level and the rest of the station runs into a bottleneck. There are not enough stairs and escalators between the platform and the mezzanine, and as a result, queues develop after every train arrival at rush hour. Similar queues are observed at the Gare du Nord RER platforms. The situation at Les Halles is especially frustrating, since it’s not a constrained station. The platforms are so wide they could very easily have four or even six escalators per access point flanking a wide staircase; instead, there are only two escalators, an acceptable situation at most stations but not at a station as important as Les Halles.

This is generally an underrated concern in the largest cities. In smaller cities, the minimum number of access points required for coverage (e.g. one per short subway platform, two per long platform) is enough even at rush hour. But once daily ridership at a station goes into the high five figures or the six figures, a crunch is unavoidable.

There are two degrees of crunch. The first, and worse, is when the capacity of the escalators and stairs is not enough to clear all passengers until the next train arrives. In practice, this forces trains to come less often, or to spread across more platforms than otherwise necessary; Penn Station’s New Jersey Transit platforms are that bad. The situation at Les Halles and Gare du Nord is a second, less bad degree of crunch: passengers clear the platform well before the next train arrives, but there’s nonetheless a significant queue at the bottom of the escalator pits. This adds 30-60 seconds to passenger trip times, a nontrivial proportion of total trip time (it’s a few percent for passengers within the city and inner suburbs). Avoiding even the less bad crunch thus has noticeable benefits to passengers.

The capacity of a horizontal walkway is 81 passengers per minute per meter of width (link, p. 7-10). This is for bidirectional travel. Unidirectional capacity is a little higher, multidirectional capacity a little lower. Subway platforms and passages are typically around 5 meters wide, so they can move 400 passengers per minute – maybe a little more since the big crunch is passengers heading out, so it’s unidirectional with a few salmons (passengers arrive at the station uniformly but leave in clumps when the train arrives). Busier stations often have exits at opposite ends of the platform, so it’s really 400*2 = 800. Queues are unlikely to form, since trains at best arrive 2 minutes apart, and it’s uncommon for a train to both be full and unload all passengers at one station.

An escalator step can be 60 cm, 80 cm, or 1 meter wide, with another 60 cm of handrail and gear space on both sides. On public transit, only the widest option is used, giving 1.6 meters of width. The theoretical capacity is 9,000 passengers per hour, but the practical capacity is 6,000-7,000 (link, p. 13), or 100-120 per minute. This is more than pedestrian walking capacity per unit of step width, but less per unit of escalator pit width. So a pedestrian walkway ending in a battery of escalators will have a queue, unless the width of the escalator bank is more than that of the walkway leading to it.

Moreover, escalators aren’t just at the end of the station. The busiest train stations have multiple access points per platform, to spread the alighting passengers across different sections of the platform. But mid-platform access points have inherently lower capacity, since they compete for scarce platform width with horizontal circulation. It appears that leaving around 2 meters on each side, and dedicating the rest to vertical circulation, is enough to guarantee convenient passenger access to the entire platform; in a crunch, most passengers take the first access point up, especially if there’s a mezzanine (which there is at Les Halles).

Should New York invest in better commuter rail operations, it will face a bigger risk of queues than Paris has. This is for two reasons. First, New York has much higher job density in Midtown than Paris has anywhere, about 200,000/km^2 vs. perhaps 100,000 around La Defense and the Opera (my figures for both areas in Paris have huge fudge factors; my figure for New York comes from OnTheMap and is exact). And second, Manhattan’s north-south orientation makes it difficult to spread demand across multiple CBD stations on many commuter rail lines. One of the underrated features of a Penn Station-Grand Central connection is that through-trains would have passengers spread across two CBD stops, but other through-running regional rail lines would not have even that – at best they’d serve multiple CBDs, with one Midtown stop (e.g. my line 4 here).

When I computed the needs for vertical circulation at a Fulton Street regional rail station in this post, I was just trying to avoid the worse kind of crunch, coming up with a way to include 16 platform-end escalators (12 up, 4 down in the morning peak) and 16 mid-platform escalators (8 up, 8 down) on a 300-meter long two-level station. It’s likely that the escalator requirement should be higher, to avoid delaying passengers by 1-1.5 minutes at a time. With four tracks (two on a Grand Central-Staten Island line, two on a Pavonia-Brooklyn line) and 12-car trains arriving every 2 minutes, in theory the station could see 240,000 incoming passengers per hour, or 4,000 per minute. In reality, splitting passengers between Grand Central and the Financial District on what I call line 4 means that a sizable majority of riders wouldn’t be getting off in Lower Manhattan. When I tried to compute capacity needs I used a limit passenger volume of 120,000 per hour, and given Midtown’s prominence over Lower Manhattan, even 90,000 is defensible.

90,000 per hour is still 1,500 per minute, or 3,000-4,000 if we are to avoid minute-long queues. A single up escalator is limited to about 100-120 people per minute, which means that twenty up escalators is too little; thirty or even forty are needed. This requires a wider platform, not for horizontal passenger circulation or for safety, but purely for escalator space, the limiting factor. I proposed an 8-meter platform, with space for four escalators per end (two ends per platform, two platforms on two different levels), but this suggests the tube diameter should be bigger, to allow 10-meter platforms and six escalators per end, giving four up escalators per end. This is 16 up escalators. Another 16-20 up escalators can be provided mid-platform: the plan for eight up escalators involved eight access points interspersed along the platform, and 10-meter platforms are wide enough width to include three escalators (two up, one down) per bank and on the border of allowing four (three up, one down).

The situation at the Midtown stations in New York is less constrained. Expected volumes are higher, but Grand Central and Penn Station both spread passengers among multiple platforms. In the near term, Penn Station needs to add more vertical circulation at the New Jersey Transit platforms. The LIRR remodeled its section of the station to add more access points in the 1990s (e.g. West End Concourse), but New Jersey Transit is only doing so now, as part of phase 1 of Moynihan Station, and it’s still not adding as many, since its platforms are shorter and don’t extend as far to the west.

Nonetheless, given the number of proposals out there for improving Penn Station, including ReThinkNYC and Penn Design’s plan, it’s important to think of longer-term plans for better vertical circulation. When I proposed eliminating Penn Station’s above-ground infrastructure, I came up with a design for six approach tracks (including a new Hudson tunnel connecting to Grand Central), each splitting into two platform tracks facing the same platform; the six platforms would each be 15 meters wide, but unlike Les Halles, each of six access points would have six escalators, four up and two down in the morning peak, or alternatively four escalators and a wide staircase (the climb is 13 meters, equivalent to a five-floor walkup). There would be ample capacity for anything; emptying a full 12-car train would take forty seconds, and it’s unlikely an entire 12-car train would empty.

Neighborhoods With Excess Capacity

In New York, the tech industry has clustered in the Meatpacking District, around 14th Street and 8th Avenue. Google’s building (the company’s largest office outside the Googleplex) is there, Samsung’s New York offices are there, startup incubators are there with co-working spaces. Stephen Smith has called for commercial upzoning there (on YIMBY three years ago, and on Twitter just now), despite NIMBY objections. He argues not only that there is pent-up demand for office space, but also that there is excess subway capacity there: “the L train’s capacity west of Union Square is essentially unlimited, after the hordes from Brooklyn headed to destinations east of Broadway change for the 4/5/6 and N/Q/R.” While his other arguments for upzoning are solid, this one is incorrect, and I’d like to explain which areas have excess capacity and which don’t.

Two years ago, I wrote this post about modeling transit crowding. The model is primitive – it assumes a one-dimensional city, 100% mode share, and independent job and residence distributions. For the purposes of this post, cities A, B, and C from the model are not relevant (they have perfect mixture of jobs and residences); cities D, E, and F, with separation of residences and jobs, are more relevant, with city F, with partial mixture, the most useful.

The results of the model are fairly predictable. In the morning peak, transit vehicles (or roads!) fill up toward the center as they pass through residential areas, and then empty in the commercial core. This means that more residences outward of the point of greatest congestion, and more jobs inward of it, add more crowding; more jobs outward of the point, and more residences inward of it, do not. More jobs on the other side of city center add to crowding, because people still ride through the point of greatest crowding.

On the L, the point of greatest crowding is between Bedford Avenue (the last stop in Brooklyn) and First Avenue (the first in Manhattan). This means that more residential development on the L in Brooklyn and more commercial development in Manhattan would add crowding – even commercial development on the West Side would attract riders living in Brooklyn, who would ride through the overcrowded segment under the East River. The other subway lines serving the Meatpacking District suffer from the same problem: those are the 2 and 3 at 7th Avenue and 14th Street, and the A, C, and E at 8th Avenue. With Second Avenue Subway having taken some crowds off the 4 and 5 on the East Side, it’s likely the 2, 3, and E are the most crowded subway lines in New York today (the A has more room). Yes, most riders on those lines get off in Midtown, but it doesn’t matter, because riders from the Upper West Side and Queens, attracted to new jobs in the Meatpacking District, would still ride through the most crowded point, at the entry to Midtown.

So if not the Meatpacking District, where is it better to add jobs, purely from the perspective of subway crowding? Superficially, the answer is to mix them across the residential parts of the city. But here, my model runs into problems with mode share. The model says that adding jobs in (say) Downtown Brooklyn increases subway crowding, because of riders from Uptown Manhattan riding to the south. Per the model, it’s best to add jobs on the side with more crowding, which is the north and Queens sectors, not the Brooklyn sector, where only the L is very crowded. This means, more jobs on the Upper East and West Sides, and maybe also in Long Island City, near Queensboro Plaza.

But in reality, there is some travel segmentation in New York. People who work on the Upper East and West Sides probably live in those neighborhoods or in Harlem and the Bronx, and people who work in Downtown Brooklyn probably live elsewhere in Brooklyn. Yes, it’s possible to commute between the Upper East Side and Downtown Brooklyn, but people would not ordinarily choose to do so – the commute is long and crowded (because of all the Midtown-bound workers), and there isn’t much saving on rent. People might still do it for various reasons, like a two-body problem or moving frequently between jobs – this is why through-running is important – but it’s much less common than living and working on the same side of city center.

So most likely, office development in Downtown Brooklyn would mainly attract ridership from within Brooklyn. Extra ridership from Uptown Manhattan and the Bronx is likely to be small. The upshot is that locations outside the most crowded point on each inbound subway line are likely to lead to large gains in subway ridership without much additional crowding.

I bring up Downtown Brooklyn and not just the Upper West and East Sides because it is better-connected to more bedroom communities by subway. These include the Lower East Side and Chinatown, Long Island City, and nearly all of Brooklyn. Long Island City is also highly accessible, from much of Queens and the parts of Brooklyn on the G train. But the Upper West and East Sides aren’t so accessible because of the lack of good east-west subway options.

Of course, the situation on the ground is different. New York is desperate to add tech jobs in Downtown Brooklyn, but the tech industry insists on clustering in the Meatpacking District. There’s only so much a city can force developers to site themselves in the areas most convenient for infrastructure. But from a long-term capacity standpoint, it’s in New York’s interest to encourage commercial development outside the Manhattan core, especially in areas that get decent subway service from multiple directions, like Long Island City, Downtown Brooklyn, and maybe Jamaica.

It would be easier if there were more service targeted at off-core destinations. This is part of why I harp on regional rail all the time – the LIRR would be able to serve Downtown Brooklyn and Jamaica better if it didn’t exist just for the benefit of suburban salarymen working in Midtown. But this also includes Triboro, which would give multidirectional service to nodes including Jackson Heights, the Bronx Hub, and Brooklyn College. This would encourage developers to build commercial at these nodes, which suffer from poor access to workers today.

Note that opening circumferential transit, in this model, has the opposite of the expected effect on radial lines. Normally, a new transit line reduces demand on parallel lines and increases demand on intersecting lines, which runs the risk of overloading them. But if a circumferential line encourages office development at intersection points with radials, it will still encourage more ridership on the radials, but this ridership will completely miss the congested inner portions of the radials.

Suspended Railways

Suspended railways are not a common mode of transportation. In Europe, the best-known example is the Wuppertal Suspension Railway, opened in 1901. Two examples exist in Japan, which is more willing to experiment with nonstandard rail technology. With essentially just these three examples in normal urban rail usage, it is hard to make generalizations. But I believe that the technology is underrated, and more cities should be considering using it in lieu of more conventional elevated or underground trains.

The reason why suspended trains are better than conventional ones is simple: centrifugal force. Train cars are not perfectly rigid – they have a suspension system, which tolerates some angle between the bogies and the carbody. Under the influence of centrifugal force, the body leans a few degrees to the outside of each curve:

 

If the train is moving away from you, and is turning left, then the outside of the curve is to your right; this is where the body leans in the image on the right. This is because centrifugal force pushes everything to the right, including in particular the carbody. This increases the centrifugal force felt by the passengers – the opposite of what a tilt system does. A train is said to have soft suspension if this degree of lean is large, and rigid suspension if it is small. The depicted image is rotated 3 degrees, which turns 1 m/s^2 acceleration in the plane of the tracks into 1.5 m/s^2 felt by the passengers; this is the FRA’s current limit, and is close to the maximum value of emergency deceleration. There are no trains with perfectly rigid suspension, but the most recent Shinkansen trains have active suspension, which provides the equivalent of 1-2 degrees of tilt.

On a straddling train, this works in reverse. A straddling train moving away from you turning left will also suspend to the right:

 

It’s almost identical, except that now the floor of the train leans toward the inside of the curve, rather than to the outside. So the suspension system reduces the lateral acceleration felt by the passengers, rather than increasing it. By softening the suspension system, it’s possible to provide an arbitrarily large degree of tilt, limited only by the maximum track safety value of lateral acceleration, which is not the limiting factor in urban rail.

This is especially useful in urban rail. Longer-distance railroads can superelevate the tracks, especially high-speed tracks, where trains have to be reliable enough for other reasons that they never have to stop in the middle of a superelevated curve. Some urban rail lines have superelevation as well, but not all do. Urban rail lines with high crowding levels routinely stop the trains in the middle of the track to maintain sufficient spacing to the train ahead; this is familiar to my New York readers as “we are being delayed because of train traffic ahead of us,” but the same routinely happens in Paris on the RER. This makes high superelevation dicey: a stopped train leans to the inside of the curve, which is especially uncomfortable for passengers. High superelevation on urban rail is also limited by the twist, i.e. the rate at which the superelevation increases per linear meter (in contrast, on intercity rail, the limiting factor is jerk, expressed in superelevation per second).

Another reason why reducing curve radius is especially useful in urban rail is right-of-way constraints. It’s harder to build a curve of radius 200 meters in a dense city (permitting 60 km/h with light superelevation) than a curve of radius 3 km outside built-up areas (permitting 250 km/h with TGV superelevation and cant deficiency). Urban rail systems make compromises about right-of-way geometry, and even postwar systems have sharp curves by mainline rail standards; in 1969, the Journal of the London Underground Railway Society listed various European limits, including Stockholm at 200 meters. The oldest lines go well below that – Paris has a single 40-meter curve, and New York has several. Anything that permits urban rail to thread between buildings (if above ground), building foundations (if underground), and other lines without sacrificing speed is good; avoiding curves that impose 30 km/h speed limits is important for rapid transit in the long run.

Suspended railways are monorails, so they run elevated. This is not inherent to the technology. Monorails and other unconventional rail technologies can go underground. The reason they don’t is that a major selling point for monorails is that their sleek structures are less visually obtrusive when elevated. But underground they can still use the same technology – if anything, the difficulty of doing emergency evacuation on an elevated suspended monorail is mitigated on an underground line, where passengers can hop to the floor of the tunnel and walk.

I’d normally say something about construction costs. Unfortunately, the technology I am plugging has three lines in regular urban operation, opened in 1901, 1970, and 1988. The 1988 line, the Chiba Monorail, seems to have cost somewhat more per km than other contemporary elevated lines in Japan, but I don’t want to generalize from a single line. Underground there should not be a cost difference. And ultimately, cost may well be lower, since, at the same design speed, suspended monorails can round tighter curves than both conventional railroads and straddle monorails.

Despite its rarity, the technology holds promise in the most constrained urban environments. When they built their next new metro lines, disconnected from the older network, cities like New York, London, Paris, and Tokyo should consider using suspended railroads instead of conventional subways.