Search results for: deinterlining

Deinterlining and Schedule Robustness

There’s an excellent Uday Schultz blog post (but I repeat myself) about subway scheduling in New York. He details some stunning incompetence, coming from the process used to schedule special service during maintenance (at this point, covering the entirety of the weekend period but also some of the weekday off-peak). Some of the schedules are physically impossible – trains are scheduled to overtake other trains on the same track, and at one point four trains are timetabled on the same track. Uday blames this on a combination of outdated software, low maintenance productivity, aggressive slowdowns near work zones, and an understaffed planning department.

Of these, the most important issue is maintenance productivity. Uday’s written about this issue in the past and it’s a big topic, of similar magnitude to the Transit Costs Project’s comparison of expansion costs. But for a fixed level of maintenance productivity, there are still going to be diversions, called general orders or GOs in New York, and operations planning needs to schedule for them. How can this be done better?

The issue of office productivity

Uday lists problems that are specific to scheduling, such as outdated software. But the software is being updated, it just happens to be near the end of the cycle for the current version.

More ominous is the shrinking size of ops planning: in 2016 it had a paper size of 400 with 377 positions actually filled, and by 2021 this fell to 350 paper positions and 284 actually filled ones. Hiring in the American public sector has always been a challenge, and all of the following problems have hit it hard:

  • HR moves extraordinarily slowly, measured in months, sometimes years.
  • Politicians and their appointees, under pressure to reduce the budget, do so stupidly, imposing blanket hiring freezes even if some departments are understaffed; those politicians universally lack the competence to know which positions are truly necessary and where three people do the job of one.
  • The above two issues interact to produce soft hiring freezes: there’s no hiring freeze announced, but management drags the process in order to discourage people from applying.
  • Pay is uncompetitive whenever unemployment is low – the compensation per employee is not too far from private-sector norms, but much of it is locked in pensions that vest after 25 years, which is not the time horizon most new hires think in.
  • The combination of all the above encourages a time clock managerial culture in which people do not try to rock the boat (because then they will be noticed and may be fired – lifetime employment is an informal and not a formal promise) and advancement is slow, and this too deters junior applicants with ambition.

Scheduling productivity is low, but going from 377 to 284 people in ops planning has not come from productivity enhancements that made 93 workers redundant. To the contrary, as Uday explains, the workload has increased, because the maintenance slowdowns have hit a tipping point in which it’s no longer enough to schedule express trains on local train time; with further slowdowns, trains miss their slots at key merge points with other lines, and this creates cascading delays.

Deinterlining and schedule complexity

One of the benefits of deinterlining is that it reduces the workload for ops planning. There are others, all pertaining to the schedule, such as reliability and capacity, but in this context, what matters is that it’s easier to plan. If there’s a GO slowing down the F train, the current system has to consider how the F interacts with every other lettered route except the L, but a deinterlined system would only have to consider the F and trains on the same trunk.

This in turn has implications for how to do deinterlining. The most urgent deinterlining in New York is at DeKalb Avenue in Brooklyn, where to the north the B and D share two tracks (to Sixth Avenue) and the N and Q share two tracks (to Broadway), and to the south the B and Q share tracks (to Coney Island via Brighton) and the D and N share tracks (to Coney Island via Fourth Avenue Express). The junction is so slow that trains lose two minutes just waiting for the merge point to clear, and a camera has to be set up pointing at the trains to help dispatch. There are two ways of deinterlining this system: the Sixth Avenue trains can go via Brighton and Broadway trains via Fourth Avenue, or the other way around. There are pros and cons either way, but the issue of service changes implies that Broadway should be paired with Fourth Avenue, switching the Q and D while leaving the B and N as they are. The reason is that the Fourth Avenue local tracks carry the R, which then runs local along Broadway in Manhattan; if it’s expected that service changes put the express trains on local tracks often, then it’s best to set the system up in a way that local and express pairings are consistent, to ensure there’s no interlining even during service changes.

This should also include a more consistent clockface timetable for all lines. Present-day timetabling practice in New York is to fine-tune each numbered and lettered service’s frequency at all times of day based on crowding at the peak point. It creates awkward situations in which the 4 train may run every 4.5 minutes and the 5, with which it shares track most of the way, runs every 5.5, so that they cannot perfectly alternate and sometimes two 4s follow in succession. This setup has many drawbacks when it comes to reliability, and the resulting schedule is so irregular that it visibly does not produce the intended crowding. Until 2010 the guideline was that off-peak, every train should be occupied to seated capacity at the most crowded point and since 2010 it has been 125% of seated capacity; subway riders know how in practice it’s frequently worse than this even when it shouldn’t be, because the timetables aren’t regular enough. As far as is relevant for scheduling, though, it’s also easier to set up a working clockface schedule guaranteeing that trains do not conflict at merge points than to fine-tune many different services.

Deinterlining and delocalization of institutional knowledge

Uday talks about New York-specific institutional knowledge that is lost whenever departments are understaffed. There are so many unique aspects of the subway that it’s hard to rely on scheduling cultures that come from elsewhere or hire experienced schedulers from other cities.

There is a solution to this, which is to delocalize knowledge. If New York does something one way, and peers in the US and abroad do it another way, New York should figure out how to delocalize so that it can rely on rest-of-world knowledge more readily. Local uniqueness works when you’re at the top of the world, but the subway has high operating costs and poor planning and operations productivity and therefore its assumption should be that its unique features are in fact bugs.

Deinterlining happens to achieve this. If the subway lines are operated as separate systems, then it’s easier to use the scheduling tools that work for places with a high degree of separation between lines, like Boston or Paris or to a large extent London and Berlin. This also has implications for what capital work is to be done, always in the direction of streamlining the system to be more normal, so that it can cover declining employee numbers with more experienced hires from elsewhere.

How Deinterlining Can Improve New York City Transit

New York is unique among the major subways of the world in the extent of interlining its network has. All routes share tracks with other routes for part of the way, except the 1, 6, 7, and L. The advantage of this system is that it permits more one-seat rides. But the disadvantages are numerous, starting with the fact that delays on one line can propagate to nearly the entire system, and the fragile timetables lead to slower trains and lower capacity. New NYCT chief Andy Byford just released a plan calling for investment in capacity, called Fast Forward, focusing on accessibility and improved signaling, but also mentioning reducing interlining as a possibility to increase throughput.

I covered the interlining issue more generally in my article about reverse branching, but now I want to explain exactly what it means, having learned more about this issue in London as well as about the specifics of how it applies to New York. In short, New York needs to reduce the extent of reverse branching as much as possible to increase train speed and capacity, and can expect serious gains in maximum throughput if it does so. It should ultimately have a subway map looking something like this:

Lessons from London

In London, there is extensive interlining on the Underground, but less so than in New York. The subsurface lines form a complex interconnected system, which also shares tracks with one branch of the Piccadilly line, but the Northern, Central, Victoria, Jubilee, and Waterloo and City lines form closed systems (and the Bakerloo line shares tracks with one Overground line). The Northern line reverse-branches: it has two central trunks, one through Bank and one through Charing Cross; one southern segment, with through-trains to both trunks; and two northern branches, each sending half its trains to each trunk. The other closed systems have just one trunk each, and as a result are easier to schedule and have higher capacity.

As the Underground moves to install the same high-capacity signaling on more and more lines, we can see what the outer limit of throughput is on each system. The Northern line’s new moving-block signaling permits 26 trains per hour on the Bank trunk and 22 on the Charing Cross trunk. When the Battersea extension opens, reverse branching on the south will end, pairing the older line to Morden with Bank and the new extension with Charing Cross, and capacity will rise to 32 tph per trunk. Planned improvements to transfer capacity at Camden Town, the northern branch point, will enable TfL to permanently pair each northern branch with one central trunk, raising capacity to 36 tph per trunk. Moreover, TfL expects moving block signaling to raise District line capacity from 24 tph to 32, keeping the current reverse branching. The Victoria line already runs 36 tph and the Jubilee line soon will too, while the Central line runs 35 tph. So 36 vs. 32 seems like the difference coming from the final elimination of reverse branching, while more extensive reverse branching reduces capacity further.

The reason complex branching reduces capacity is that, as delays propagate, the schedule needs to incorporate a greater margin of error to recover from unexpected incidents. It also slows down the trains, since the trains are frequently held at merge points. The general rule is that anything that increases precision increases capacity (such as automation and moving block signaling) and anything that reduces precision reduces capacity; reverse branching reduces timetable precision, because each train can be delayed by incidents on more than one line, making delays more common.

What deinterlining in New York entails

NYCT has its work cut out for it when it comes to deinterlining. There are eight different points in the system where reverse-branching occurs – that is, where lines that do not share track in Manhattan (or on the G trunk outside Manhattan) share tracks elsewhere.

  1. The 2 and 5 trains share tracks on the Nostrand Avenue Line.
  2. The 2 and 5 also share tracks in the Bronx.
  3. The A and C trains share tracks on the two-track narrows through Lower Manhattan and Downtown Brooklyn.
  4. The A and D share the express tracks on Central Park West while the B and C share the local tracks.
  5. The E and F share the express tracks on Queens Boulevard, while the M and R share the local tracks, the E and M share the tunnel from Queens to Manhattan, and the N, R, and W share a different tunnel from Queens to Manhattan.
  6. The B and Q share tracks in Brooklyn, as do the D and N.
  7. The F and G share tracks in South Brooklyn.
  8. The M shares the Williamsburg Bridge tracks with the J/Z but runs in Manhattan on the same tracks as the F.

NYCT should work to eliminate all of the above reverse branches. The easiest to start with is #6: the junction at DeKalb Avenue should be set to keep the B and D trains together and to keep the N and Q together rather than to mix them so that the B shifts to the Q tracks and the D to the N tracks. This requires no changes in physical infrastructure, and has especially high benefits as the junction delays trains by several minutes in each direction. Moreover, the loss of one-seat rides is minimal: the BDFM and NQRW run closely parallel in Manhattan and intersect with a transfer at Herald Square in addition to the inconveniently long BQ/DNR transfer at Atlantic Avenue.

Another relatively easy reverse branch to eliminate is #8, a recent introduction from the 2010 service cuts. Previously, today’s M route in Queens and Manhattan was covered by the V train, which turned on the Lower East Side, while the M ran the same route as the J/Z, merging onto the R and thence the N in Brooklyn at rush hour. Today’s route is thus an M-V merger, which railfans including myself hoped would help decongest the L by creating an alternative route from Williamsburg to Midtown. Unfortunately, such decongestion has not happened, perhaps because gentrification in Williamsburg clusters near the L and not near the J or M.

Harsh decisions

Fixing the reverse-branching at DeKalb Avenue and on the Williamsburg Bridge is painless. The other reverse branches require a combination of hard decisions and new infrastructure.

Fixing reverse branches #3 and #4 requires no capital investment, just political will. Reverse branch #4 is there because there’s demand for two routes’ worth of capacity in the tunnel from Brooklyn but there’s only one express line on Eighth Avenue, and that in turn is the result of reverse branch #3; thus these two issues should be tackled together.

NYCT should decide between having the A and C trains run express between 145th and 59th Streets and the B and D trains run local, or the other way around. This is not an easy decision: either Washington Heights or Grand Concourse would get consigned to local trains. North of 145th the total number of boardings is 102,000 at B/D stations compared with 79,000 on the A/C, but conversely Concourse riders can change to the express 4 trains whereas Washington Heights’ only alternative is the local 1. However the A and C run, express or local, the E should run the opposite in Manhattan – it can merge to either the local or express tracks – and the express trains should continue to Brooklyn. The map I made doesn’t distinguish local from express service, but my suspicion is that Washington Heights should get express trains, on account of its long commutes and lack of fast alternatives.

The same problem of harshness occurs in reverse-branch #5. In theory, it’s an easy fix: there are three track pairs in Queens (Astoria, Queens Boulevard local, Queens Boulevard express) feeding three tunnels to Manhattan (63rd, 60th, and 53rd Streets). In practice, the three Manhattan trunks have astonishingly poor transfers between them in Midtown. Nonetheless, if it does nothing else, NYCT should remove the R from Queens Boulevard and route all 60th Street Tunnel trains to Astoria; together with fixing DeKalb Avenue, this would separate the lettered lines into two closed systems, inherited from the BMT and IND.

However, undoing the connection between the BMT and the IND probably requires constructing a transfer station in Long Island City between Queensboro Plaza and Queens Plaza, which involves a few hundred meters of underground walkway. Even then, the connection cannot possibly be convenient. The saving grace is that Eighth Avenue, Sixth Avenue, and Broadway are close enough to one another that passengers can walk to most destinations from any line.

Subsequently, NYCT should make a decision about whether to send express Queens Boulevard trains to 63rd Street and Sixth Avenue and local trains to 53rd and Eighth, as depicted in the above map, or the other way around. The problem is that the merge point between 53rd and 63rd Street Tunnels is one station east of Queens Plaza, at a local station, and thus the true transfer point is Roosevelt Avenue, far to the east. Riders on the local stations west of Roosevelt would get no choice where to go (though they get little choice today – both the E and M serve 53rd Street, not 63rd). The argument to do things as I depict them is to give the local stations access to 53rd Street; the argument to switch the lines is that there is more demand on 53rd than 63rd and also more demand on the express tracks than the local tracks, so the busiest lines should be paired. However, this in turn runs into turnback capacity limitations on the E in Manhattan, at the World Trade Center bumper tracks.

Potentially, NYCT could try to convert 36th Street into an express station, so that passengers could connect cross-platform. But such a dig would be costly and disruptive to operations. There were plans to do this at 59th Street on the 1/2/3 a few decades ago, for the transfer to the A/B/C/D, but nothing came of them.

Where new infrastructure is needed

The remaining reverse branches get increasingly more difficult. Already #7 requires new turnouts. The South Brooklyn trunk line has four tracks, but there’s not enough demand (or space in Manhattan) to fill them, so only the local tracks are used. There are occasional railfan calls for express service using the F, but it’s better to instead use the express tracks to segregate the G from the F. The G could be turned at Bergen Street on the local tracks, while the F could use the express tracks and then transition to the locals on new turnouts to be constructed at Carroll Street.

Also in the category of requiring new turnouts is #1: Rogers Avenue Junction is set up in a way that briefly forces the 2, 3, and 5 trains to share a short segment of track, limiting capacity. This can be resolved with new turnouts just east of the junction, pairing Nostrand Avenue Line with the local tracks and the West Side and the portion of the Eastern Parkway Line east of Nostrand with the express tracks and the Lexington Avenue Line. Trains on Eastern Parkway could either all go local, or keep the current mixture of local trains to New Lots (currently the 3) and express trains to Utica (currently the 4), skipping a total of two stations. This fix also reduces passengers’ access to one-seat rides, but at least there is a reasonable cross-platform transfer at Franklin Avenue, unlike on Queens Boulevard or at 145th Street and St. Nicholas.

And then there is #2, by far the most difficult fix. Demand on the White Plains Road branch in the Bronx is too strong to be a mere branch: the combined number of boardings at all stations is 166,000 per weekday, and besides, the line branches to Dyre Avenue near its outer end and thus needs the frequency of either a trunk or two branches to ensure adequate service to each other branch. This is why it gets both the 2 and 5 trains. There is unfortunately no infrastructure supporting a switch eliminating this track sharing: the 4 and 5 trains could both use this line, but then the 2 has no way of connecting to Jerome Avenue Line without new tunnels.

On the map, I propose the most obtrusive method of fixing this problem: cutting the 3 trains to a shuttle, with a new pocket track at 135th Street, letting passengers transfer to the 2, ideally cross-platform. With all through-trains running on the 2, there is no need (or space) for the 5 on White Plains Road, and instead the 5 should help boost the frequency on Jerome Avenue. In addition, some work is required at Woodlawn, which currently has bumper tracks, fine for a single branch but not for a non-branching trunk line (the bumper tracks on the L limit throughput to 26 tph no matter how good the electronics are).

Additional infrastructure suggested by deinterlining

Deinterlining is a service increase. Lines that today only get half or two-thirds service would get full trunk frequency: Second Avenue Subway would get the equivalent of the Q and N trains, the Astoria Line would get the entirety of 60th Street Tunnel’s capacity, Eighth Avenue would get more express trains, and 63rd Street Line and the South Brooklyn Line would get more than just the half-service of the F. With six track pairs on the lettered lines through Midtown and six north and east (Central Park West*2, Second Avenue, Astoria, Queens Boulevard*2), there is no room for natural branching to give more service to busy areas than to less busy ones.

One solution to this situation is targeted development on weak lines. Even with half service, South Brooklyn has underfull F trains, and Southern Brooklyn’s B, D, N, and Q trains aren’t much busier, making this entire area an attractive target for upzoning.

However, it’s more interesting to look at lines with extensions that suggest themselves. Second Avenue Subway has the obvious extension north to Harlem in phase 2, and a potential subsequent extension under 125th Street to Broadway, which is less obvious but popular among most area railfans (including one of my inside sources at NYCT). The Astoria Line has a natural extension to LaGuardia, ideally elevated over Ditmars to capture local ridership on Astoria as well as airport traffic; while the steel el structures in New York are soundboxes, it is possible to build quieter els using concrete (as on the 7 el over Queens Boulevard in Sunnyside) or a mixture of concrete columns and a steel structure (as on the Metro 2 and 6 els here in Paris).

The Nostrand Avenue Line provides an especially interesting example of a subway extension suggested by deinterlining. The terminal, Flatbush Avenue, was intended to be temporary, and as a result has limited turnback capacity. To prevent it from constraining the entire 2 route, which became the city’s most crowded even before Second Avenue Subway began decongesting the 4 and 5, it would be prudent to extend the line to Sheepshead Bay as the city intended when it planned the line in the 1910s.

In contrast, a subway extension under Utica, a stronger bus corridor than Nostrand with a strong outer anchor at Kings Plaza, loses value under deinterlining. It could only get a branch and thus have lower capacity than Nostrand. It would also definitely force branching on the express trains, whereas without such an extension they could run as a single unbranched line between Woodlawn and New Lots Avenue via Jerome Avenue, Lexington Avenue, and Eastern Parkway. A Utica subway should wait until there is political will to fund an entirely new crossing into Manhattan, presumably via Williamsburg to help decongest the L.

A second extension I have occasionally mooted, a subway under Northern, loses value even more. Such a subway would be a fourth trunk line in Queens and have to come at the expense of capacity on Queens Boulevard. It is only supportable if there is an entirely new tunnel to Midtown, passing under the mess that is the tracks in Long Island City.

A deinterlined New York City Subway

Fast Forward proposes moving block signaling on the most crowded subway segments, but typically only on trunks, not branches, and in some cases not even entire trunks. But in the long term, New York should transition to moving blocks and automation on all lines – at the very least the highly automated system used on the L, but ideally fully driverless operation, in recognition that wages are going up with economic growth but driver productivity isn’t. Simultaneously, deinterlined operations should allow tph counts in the mid 30s or even more (Metro 13 here runs 38 tph and Metro 14 runs 42).

Instead of the potpourri of lines offered today, there would be fewer, more intense lines. Nomenclature would presumably change to deal with the elimination of some services, clarifying the nature of the subway as a nine-line system in which five lines have four tracks and four lines have two. Each of these fourteen track pairs should be able to support a train every 90-105 seconds at the peak; not all lines have the demand for such frequency, and some have capacity-limiting bumper tracks that aren’t worth fixing (e.g. the 1 at Van Cortlandt Park), but many lines have the infrastructure and the demand for such capacity, including the express lines entering Midtown from Uptown or Queens.

Off-peak, too, service would improve. There is ample capacity outside rush hour, but turning the system into one of lines arriving every 4-5 minutes with strategic transfers rather than every 8-10 minutes would encourage people to take the trains more often. The trains would simultaneously be faster and more reliable, since incidents on one line would wreck service on other trains on the same line but leave the rest of the network unaffected.

With service improvements both during and outside rush hour, New York could expect to see substantial increases in ridership. Raising peak frequency from the current 24 tph to 36 tph on the busiest lines (today’s 2/3, 4/5, A/D, and E/F) is equivalent to building an entirely new four-track subway trunk line, and can be expected to produce similar benefits for passengers. The passups that have become all too familiar for riders on the 4, L, and other busy trains would become a thing of the past unless ridership rose 50% to match the increase in capacity.

New York Can’t Build, LaGuardia Rail Edition

When Andrew Cuomo was compelled to resign, there was a lot of hope that the state would reset and finally govern itself well. The effusive language I was using at the time, in 2021 and early 2022, was shared by local advocates for public transportation and other aspects of governance. A year later, Governor Hochul has proven herself to be not much more competent than Cuomo, differing mainly in that she is not a violent sex criminal.

Case in point: the recent reporting that plans for rail to LaGuardia Airport are canceled, and the option selected for future development is just buses, makes it clear that New York can’t build. It’s an interesting case in which the decision, while bad, is still less bad than the justification for it. I think an elevated extension of the subway to LaGuardia is a neat project, but only at a normal cost, which is on the order of maybe $700 million for a 4.7 km extension, or let’s say $1 billion if it’s mostly underground. At New York costs, it’s fine to skip this. What’s not fine is slapping a $7 billion pricetag on such an endeavor.

LaGuardia rail alignments

On my usual base map of a subway system with some lines swapped around to make the system more coherent but no new construction, here are the various rail alignments to the airport:

A full-size image can be found here. All alternatives are depicted as dashed lines; the subway extension is depicted in yellow in the same color as the Astoria Line, and would be elevated until it hit airport grounds, while the other two options, depicted as thinner black lines, are people movers or air trains. The air train option going east of airport grounds was Cuomo’s personal project and, since it went the wrong way, away from Manhattan, it was widely unpopular among anyone who did not work for Cuomo and was for all intents and purposes dead shortly after Hochul took office.

The issue of construction costs

Here’s what the above-linked New York Times article says about the rail alignments.

The panel’s three members — Janette Sadik-Khan, Mike Brown and Phillip A. Washington — said in a statement that they were unanimous in recommending that instead of building an AirTrain or extending a subway line to the airport, the Port Authority and the transportation authority should enhance existing Q70 bus service to the airport and add a dedicated shuttle between La Guardia and the last stop on the N/W subway line in Astoria.

The panel agreed that extending the subway to provide a “one-seat ride” from Midtown was “the optimal way to achieve the best mass transportation connection.” But they added that the engineers that reviewed the options could not find a viable way to build a subway extension to the cramped airport, which is hemmed in by the Grand Central Parkway and the East River.

Even if a way could be found to extend the subway that would not interfere with flight operations at La Guardia, the analysis concluded, it would take at least 12 years and cost as much as $7 billion to build.

The panel realized that the best option is an extension of the subway. Such an extension would be about 4.7 km long and around one third underground, or potentially around 5 km and entirely above-ground if for some reason tunneling under airport grounds were cost-prohibitive. This does not cost $7 billion, not even in New York. We know this, because Second Avenue Subway phase 1 was, in today’s money, around $2.2 billion per km, and phase 2 is perhaps a little more. There are standard subway : elevated cost ratios out there; the ones that emerge from our database tend to be toward the higher end perhaps, but still consistent with a ratio of about 2.5.

Overall, this is in theory pretty close to $7 billion for a one-third underground extension from Astoria to the airport. But in practice, the tunneling environment in question is massively easier than both phases of Second Avenue Subway – there’s plenty of space for cut-and-cover boxes in front of the terminal, a more controllable utilities environment, and not much development in the way of the elevated sections, which are mostly in an industrial zone to be redeveloped.

Does New York want to build?

New York can’t build. But to a significant extent, New York doesn’t even want to build. The report loves finding excuses why it’s not possible: they are squeamish about tunneling under the runways, they are worried an above-ground option would take lanes from the Grand Central Parkway (which a rail link would substitute for at higher capacity), they are worried about federal waivers.

In truth, in a constrained city, everything is under a waiver. In comments years ago, Richard Mlynarik pointed out that the desirable standard for railroad turnouts is that they should be straight – that is, the straight path should be on straight track, while the speed-restricted diverging path should curve away. But in practice, German train stations are full of curved turnouts, on which both paths are on a curve, because in a constrained urban zone it’s not possible to realize the desired standard, and a limit value is required. The same is true of any other engineering standard for a railroad, such as curve radii.

The issue of waivers is not limited to engineering or to rail. Roads are supposed to follow design standards, but land-constrained urban motorways are routinely on waivers. Even matters of safety can be grandfathered occasionally on a case-by-case basis. Financial and social standards are waived so often for urban megaprojects that it’s completely normal to decide them on a case-by-case basis; the United States doesn’t even have formal benefit-cost analyses the way Europe does.

And I’ve seen how American agencies are reluctant to even ask for waivers for things that politicians don’t really care about. Richard again brings up the example of platform heights on the San Francisco Peninsula: Caltrain rebuilt all platforms to a standard that didn’t have any level boarding, on the grounds that high platforms would interfere with oversize freight, which does not run on the line, and which the relevant state regulator, CPUC, indicated that they’d approve a waiver from if only the railroad asked. I have just seen an example of a plan to upgrade some stations in the Northeast that is running into trouble because the chosen construction material isn’t made in the United States, and even though “there’s no suitable made in America alternative” is legal grounds for a waiver from Buy America rules, the agency doesn’t so far seem interested in asking.

In general, New York can’t build. But in this case, it seems uninterested in even trying.

The bus alternative

Instead of a rail link, the plan now is to improve bus service. Here’s the New York Times story again:

The estimated $500 million in capital spending would also go toward creating dedicated bus lanes along 31st Street and 19th Avenue in Queens and making the Astoria-Ditmars Blvd. station on the N and W lines accessible to people with disabilities, the Port Authority said. Some of that money could also be spent to create a mile-long lane exclusive to buses on the northbound Brooklyn-Queens Expressway between Northern Boulevard and Astoria Boulevard, the Port Authority said.

Among the criticisms of the AirTrain plan was its indirect route. Arriving passengers bound for Manhattan would have had to travel in the opposite direction to catch a subway or L.I.R.R. train at Willets Point. The Port Authority chose that route, alongside the parkway, to minimize the need to acquire private property. Community groups were also concerned about the impact on property values in the neighborhoods near La Guardia in northern Queens.

To be very clear, it does not cost $500 million to make a station wheelchair-accessible. In New York, the average cost is around $70 million in 2021 dollars, with extensive contingency, planned by people who’d rather promise 70 and deliver 65 than promise 10 and deliver 12. In Madrid, the cost is around 10 million euros per station, with four elevators (the required minimum is three), and in Milan, shallow three-elevator station retrofits are around 2 million per station. Transfer stations cost more, proportionately to the number of lines served, but Astoria-Ditmars is not a transfer station and has no such excuse. So where is the other $430 million going?

The answer cannot just be bus lanes on 31st Street (on which the Astoria Line runs) or 19th Avenue (the industrial road the indicated extension on the map would run on). Bus lanes do not cost $430 million at this scale. They don’t normally cost anything – red paint and “bus only” markings are a rounding error, and bus shelter is $80,000 per stop with Californian cost control (to put things in perspective, I heard a $10,000-15,000 quote, in 2020 dollars, from a smaller American city).

Schedule Planners as a Resource

The Effective Transit Alliance published its statement on Riders Alliance’s Six-Minute Service campaign, which proposes to run every subway line in New York and the top 100 bus routes every (at worst) six minutes every day from morning to evening. We’re positive on it, even more than Riders Alliance is. We go over how frequency benefits riders, as I wrote here and here, but also over how it makes planning easier. It is the latter benefit I want to go over right now: schedule planning staff is a resource, just as drivers and outside capital are, and it’s important for transit agencies to institute systems that conserve this resource and avoid creating unnecessary work for planners.

The current situation in New York

Uday Schultz writes about how schedule planning is done in New York. There’s an operations planning department, with 350 budgeted positions as of 2021 of which 284 are filled, down from 400 and 377 respectively in 2016. The department is responsible for all aspects of schedule planning: base schedules but also schedules for every service change (“General Order” or GO in short).

Each numbered or lettered route is timetabled on it own. The frequency is set by a guideline coming from peak crowding: at any off-peak period, at the most crowded point of a route, passenger crowding is supposed to be 25% higher than the seated capacity of the train; at rush hour, higher standee crowding levels are tolerated, and in practice vary widely by route. This way, two subway routes that share tracks for a long stretch will typically have different frequencies, and in practice, as perceived by passengers, off-peak crowding levels vary and are usually worse than the 25% standee factor.

Moreover, because planning is done by route, two trains that share tracks will have separate schedule plans, with little regard for integration. Occasionally, as Uday points out, this leads to literally impossible schedules. More commonly, this leads to irregular gaps: for example, the E and F trains run at the same frequency, every 4 minutes peak and every 12 minutes on weekends, but on weekends they are offset by just 2 minutes from each other, so on the long stretch of the Queens Boulevard Line where they share the express tracks, passengers have a 2-minute wait followed by a 10-minute wait.

Why?

The current situation creates more work for schedule planners, in all of the following ways:

  • Each route is run on its own set of frequencies.
  • Routes that share tracks can have different frequencies, requiring special attention to ensure that trains do not conflict.
  • Each period of day (morning peak, midday, afternoon peak, evening) is planned separately, with transitions between peak and off-peak; there are separate schedules for the weekend.
  • There are extensive GOs, each requiring not just its own bespoke timetable but also a plan for ramping down service before the start of the GO and ramping it up after it ends.

This way, a department of 284 operations planners is understaffed and cuts corners, leading to irregular and often excessively long gaps between trains. In effect, managerial rules for how to plan trains have created makework for the planners, so that an objectively enormous department still has too much work to do and cannot write coherent schedules.

Creating less work for planners

Operations planners, like any other group of employees, are a resource. It’s possible to get more of this resource by spending more money, but office staff is not cheap and American public-sector hiring has problems with uncompetitive salaries. Moreover, the makework effect doesn’t dissipate if more people are hire – it’s always possible to create more work for more planners, for example by micromanaging frequency at ever more granular levels.

To conserve this resource, multiple strategies should be used:

Regular frequencies

If all trains run on the same frequency all day, there’s less work to do, freeing up staff resources toward making sure that the timetables work without any conflict. If a distinction between peak and base is required, as on the absolute busiest routes like the E and F, then the base should be the same during all off-peak periods, so that only two schedules (peak and off-peak) are required with a ramp-up and ramp-down at the transition. This is what the six-minute service program does, but it could equally be done with a more austere and worse-for-passengers schedule, such as running trains every eight minutes off-peak.

Deinterlining

Reducing the extent of reverse-branching would enable planning more parts of the system separately from one another without so much conflict. Note that deinterlining for the purposes of good passenger service has somewhat different priorities from deinterlining for the purposes of coherent planning. I wrote about the former here and here. For the latter, it’s most important to reduce the number of connected components in the track-sharing graph, which means breaking apart the system inherited from the BMT from that inherited from the IND.

The two goals share a priority in fixing DeKalb Avenue, so that in both Manhattan and Brooklyn, the B and D share tracks as do the N and Q (today, in Brooklyn, the B shares track with the Q whereas the D shares track with the N): DeKalb Junction is a timetabling mess and trains have to wait two minutes there for a slot. Conversely, the main benefit of reverse-branching, one-seat rides to more places, is reduced since the two Manhattan trunks so fed, on Sixth Avenue and Broadway, are close to each other.

However, to enable more convenient planning, the next goal for deinterlining must be to stop using 11th Street Connection in regular service, which today transitions the R from the BMT Broadway Line and 60th Street Tunnel to the IND Queens Boulevard local tracks. Instead, the R should go where Broadway local trains go, that is Astoria, while the Broadway express N should go to Second Avenue Subway to increase service there. The vacated local service on Queens Boulevard should go to IND trunks in Manhattan, to Eighth or Sixth Avenue depending on what’s available based on changes to the rest of the system; currently, Eighth Avenue is where there is space. Optionally, no new route should be added, and instead local service on Queens Boulevard could run as a single service (currently the M) every 4 minutes all day, to match peak E and F frequencies.

GO reform

New York uses too many GOs, messing up weekend service. This is ostensibly for maintenance and worker safety, but maintenance work gets done elsewhere with fewer changes (as in Paris or Berlin) or almost none (as in Tokyo) – and Berlin and Tokyo barely have nighttime windows for maintenance, Tokyo’s nighttime outages lasting at most 3-4 hours and Berlin’s available only five nights a week. The system should push back against ever more creative service disruptions for work and demand higher maintenance productivity.

More on Six-Minute Service in New York

Two years ago I wrote about how New York should aim to run every bus and subway service every six minutes off-peak. Buses would require a combination of aggressive bus redesign and speedup treatments for this to be viable. The subway already has very low variable operating costs off-peak and such a boost in frequency would naturally increase efficiency; New York City Transit gets around 550 service-hours annually per train driver, whereas the Berlin U-Bahn with its flat all-day schedule gets around 900. But now, the more mainstream New York-area transit advocacy group Riders’ Alliance has its own proposal for six-minute service, which it has aggressive marketed using the hashtag #6minuteservice.

This is a good campaign and I hope more people in the region take notice and push for it until the state implements it in full. The impact on passenger convenience is massive, not just in the form of shorter waits but also higher reliability coming from better timetabling, and hopefully also slightly more speed coming from said higher reliability. The proposal says that it would take $250 million a year in extra spending to effect this system, and it’s unknown but plausible that it would increase ridership by enough to defray this cost entirely, even without any efficiency treatments to reduce unit costs.

What’s in the Riders’ Alliance proposal?

Between 5 am and 9 pm on weekdays, and between 8 am and 10 pm on weekends, all subway routes and the top 100 bus routes in the city should run at worst every six minutes. This echoes a report by the comptroller’s office from last year, recommending this as an alternative to rush hour-focused service by bringing up corona-related ridership decreases.

It’s not stated but I think the subway routes in question are reckoned by letter or number, which means the A train runs every six minutes but each of its two branches runs every 12. This is fine – the two branches of the A are exceptionally far out, which is why a single service splits to them, where elsewhere in New York each branch gets its own number or letter.

The implications for timetabling

Timetabling a consistent all-day service is much easier than timetabling bespoke service patterns. The Riders’ Alliance proposal aims to face the general public rather than planners and therefore omits this benefit, but this benefit reaches passengers as well, in non-obvious ways.

First, if all trains and buses run every six minutes, then it’s possible to set up clockface timetables. These don’t matter very much if they run every six minutes, but they do if they run every 12, as I expect the two A branches to. The same is true of buses that branch: some outer ends may run every 12 minutes, in which case they can and should run on repeating clockface timetables that passengers can memorize. Passengers who can remember “my bus leaves at :01, :13, :25, :37, and :49” without having to consult timetables or trip planners all the time are likelier to take the trip; this was my commute for a year in Vancouver.

The A train today runs every 15 minutes on each branch but it’s not on a consistent clockface schedule, which depresses ridership. In effect, current practice is little different from what Swiss planners warn of: they say the best way to reduce ridership is to run service every 11, 13, or 17 minutes, rather than every 12 or 15 on a clockface pattern.

Second, if all trains run on the same frequency, then service planning on a complexly interlined system like New York’s becomes more tractable. Today, every train runs on a separate frequency, often different from the services it shares track with. The 2 and 3 trains share track most of the way, from Franklin Avenue to 135th Street, but the 2 is just a little more frequent, resulting in the following northbound timetable at Franklin:

10:03: 2
10:07: 3
10:12: 2
10:15: 3
10:21: 2
10:28: 3
10:32: 2
10:34: 3
10:37: 2
10:41: 3
10:43: 2
10:49: 2
10:51: 3
10:57: 3
11:01: 2
11:03: 3
11:09: 2
11:15: 3
11:17: 2
11:22: 3
11:24: 2
11:28: 3

This is irregular both on the trunk and on each individual service – the 2 on average runs every eight minutes but has a 12-minute gap, and the 3 runs on average every nine but also has a 12-minute gap. It’s an unavoidable consequence of the combination of extensive reverse-branching and subway frequency guidelines that run different services at different headways. The six-minute service proposal straightens this by aligning the trains to a single frequency, with regular alternation between successive trains on trunks.

And third, another benefit of a regular frequency to planning is that schedule planners can reliably avoid merge conflicts. This, in turn, speeds up service, which is full of planned delays and schedule padding at pain points. It’s not a full substitute for deinterlining, which would eliminate the merge conflicts at the worst junctions, but it makes it viable to no longer write impossible schedules with the planning department that New York City Transit has.

Service quality and demographics

Both Riders’ Alliance and the comptroller report it uses as its source point out demographic differences between peak and off-peak riders: rush hour subway commuters have a median income of $50,783 a year, even higher (slightly) than drivers, but off-peak subway commuters have a median income of $37,048 and bus commuters have a median income of $30,374.

In both reports this is taken to be indicative that off-peak service is mostly for poorer people, but it’s not the right analysis. The picture that emerges from the data is not that in general rush hour commuters outearn off-peak commuters; for one, most off-peak commutes are done by car, not by public transportation. Rather, what’s going on is that off-peak public transit quality is bad and this suppresses ridership among those who can afford a car.

By the same token, we can look at the incomes of commuters in regions of the United States that have no public transit to speak of – maybe some buses or even a few trains but with rounding-error ridership and low single-digit modal split. In metro New York, public transit and car commuters have about the same median income, and in some secondary transit cities like Chicago public transit commuters actually outearn drivers, since service to non-CBD destinations is so bad it suppresses ridership below median income more than above it. But in places like Los Angeles, the median income of transit commuters is not much more than half that of car commuters, because service quality is so bad that anyone who can afford to drive does.

The upshot of this is that better off-peak transit service is going to increase the average income of off-peak transit users, by attracting people who currently drive. This is also going to lead to higher-socioeconomic status shifts: higher levels of degree attainment, a larger proportion of white riders, a larger proportion of native-born riders.

I bring this up because a rise in the relative average income of users as service quality improves means the improvement is working as intended. It doesn’t mean the subway is gentrifying or turns away poorer riders, it just means it no longer repels riders who can afford to drive. This is important, because too much American transit planning is based on market segmentation in which service is supposed to be for a specific class of rider, and if the demographics are changing it means it’s being revamped for a different class. In reality, there’s just one transit system for one city and income differences are indicative of quality differences and not of inherent differences in the travel market.

How much does this cost? What is the ridership impact?

The Riders’ Alliance proposal says the additional cost of the program is $250 million a year in operating expenses. In 2019, NYCT spent $8.8 billion on operations and got $4.6 billion in fares, so this is in theory a 6% increase in subsidy, and in practice a little less as better service attracts more fare-paying riders. This is without any concurrent attempts to use the increase in service to increase efficiency (read: reduce unit staffing levels) and, I think, without bus speedups that permit much higher frequency for the same cost.

It’s unclear what the revenue impact should be; the ridership impact can be estimated from longstanding results in the literature about ridership-frequency elasticity, which in the case of NYCT should be about 0.4. The proposal increases off-peak service on the subway by around 50% in principle and a bit more in practice because of the reduced variability in frequency, say two-thirds: most lines are to go from 10- to six-minute headways and the rest, which are mostly more frequent than this, get a smaller increase that we round up to two-thirds by taking the impact of higher reliability into account. This means an increase in off-peak ridership of around 23%. The bus impact is even larger – in Brooklyn the median bus headway is right between 12 and 15 minutes, and even taking into account that the busiest buses do much better, this is close to a doubling of the effective frequency.

In turn, most ridership is off-peak. In 2019, peak (7-10 am) ridership into the Manhattan core was 923,000 per weekday, amounting to 44% of ridership entering the Manhattan core on a weekday, or around 33% of all inbound weekday ridership and 27% of all ridership. Even adding a bit to account for peak ridership that doesn’t enter Manhattan, only about a third of subway ridership in New York was at the peak before corona; the peak share has fallen since, but is slowly creeping back up as workers slowly return to the office. Raising two-thirds of ridership by 23% is massive – it’s a 15% systemwide increase for a much smaller increase in operating costs, and a somewhat larger increase in bus ridership to boot.

Unfortunately, I can’t turn this into a revenue impact estimate. While the demographics in the section above specify off-peak commuters, the studies that my ridership estimate is based on measure riders, including peak commuters who ride more often for non-work trips. Such riders already have monthly passes, so making it easier for them to ride is excellent for the city’s long-term health but doesn’t defray the added cost. Converted riders who are not already on the system as well as the odd peak rider who doesn’t already have a pass do generate more revenue, but I don’t know how many there are; these need to be a little more than a third of the overall increase in ridership to fully defray costs, which sounds plausible to me.

Public Transportation in the Southeastern Margin of Brooklyn

Geographic Long Island’s north and south shores consist of series of coves, creeks, peninsulas, and barrier islands. Brooklyn and Queens, lying on the same island, are the same, and owing to the density of New York, those peninsulas are fully urbanized. In Southeastern Brooklyn, moreover, those peninsulas are residential and commercial rather than industrial, with extensive mid-20th century development. Going northeast along the water, those are the neighborhoods of Manhattan Beach, Gerritsen Beach, Mill Basin, Bergen Beach, Canarsie, Starrett City, and Spring Creek. The connections between them are weak, with no bridges over the creeks, and this affects their urbanism. What kind of public transportation solution is appropriate?

The current situation

The neighborhoods in the southeastern margin of Brooklyn and the southern margin of Queens (like Howard Beach) are disconnected from one another by creeks and bays; transportation arteries, all of which are currently streets rather than subway lines, go north and northwest toward city center. At the outermost margin, those neighborhoods are connected by car along the Shore Parkway, but there is no access by any other mode of transportation, and retrofitting such access would be difficult as the land use near the parkway is parkland and some auto-oriented malls with little to no opportunity for sprawl repair. The outermost street that connects these neighborhoods to one another is Flatlands, hosting the B6 and B82 buses, and if a connection onward to Howard Beach is desired, then one must go one major street farther from the water to Linden, hosting the B15.

For the purposes of this post, the study area will be in Brooklyn, bounded by Linden, the Triboro/IBX corridor, and Utica:

This is on net a bedroom community. In 2019, it had 85,427 employed residents and 39,382 jobs. Very few people both live and work in this area – only 4,005. This is an even smaller proportion than is typical in the city, where 8% of employed city residents work in the same community board they live in – the study zone is slightly smaller than Brooklyn Community Board 18, but CB 18 writ large also has a lower than average share of in-board workers.

In contrast with the limited extent of in-zone work travel, nearly all employed zone residents, 76,534, work in the city as opposed to its suburbs (and 31,685 of the zone’s 39,382 jobs are held by city residents). Where they work looks like where city workers work in general, since the transportation system other than the Shore Parkway is so radial:

Within the zone, the southwestern areas, that is Mill Basin and Bergen Beach, are vaguely near Utica Avenue, hosting the B46 and hopefully in the future a subway line, first as an extension of the 4 train and later as an independent trunk line.

To the northeast, Canarsie, Starrett City, and Spring Creek are all far from the subway, and connect to it by dedicated buses to an outer subway station – see more details on the borough’s bus map. Canarsie is connected to the L subway station named after it by the B42, a short but high-productivity bus route, and to the 3 and 4 trains at Utica by the B17, also a high-productivity route. Starrett City does not have such strong dedicated buses: it is the outer terminus of the circumferential B82 (which is very strong), but its dedicated radial route, the B83 to Broadway Junction, is meandering and has slightly below-average ridership for its length. Spring Creek is the worst: it is a commercial rather than residential area, anchored by the Gateway Center mall, but the mall is served by buses entering it from the south and not the north, including the B83, the B84 to New Lots on the 3 (a half-hourly bus with practically no ridership), the rather weak B13 to Crescent Street and Ridgewood, and the Q8 to Jamaica.

The implications for bus design

The paucity of east-west throughfares in this area deeply impacts how bus redesign in Brooklyn ought to be done, and this proved important when Eric and I wrote our bus redesign proposal.

First, there are so few crossings between Brooklyn and Queens that the routes crossing between the two boroughs are constrained and can be handled separately. This means that it’s plausible to design separate bus networks for Brooklyn and Queens. In 2018 it was unclear whether they’d be designed separately or together; the MTA has since done them separately, which is the correct decision. The difficulty of crossings argues in favor of separation, and so does the difference in density pattern between the two boroughs: Brooklyn has fairly isotropic density thanks to high-density construction in Coney Island, which argues in favor of high uniform frequency borough-wide, whereas Queens grades to lower density toward the east, which argues in favor of more and less frequent routes depending on neighborhood details.

Second, the situation in Starrett City is unacceptable. This is an extremely poor, transit-dependent neighborhood, and right now its bus connections to the rest of the world are lacking. The B82 is a strong bus route but many rush hour buses only run from the L train west; at Starrett City, the frequency is a local bus every 10-12 minutes and another SBS bus every 10-12 minutes, never overlying to produce high base frequency. The B83 meanders and has low ridership accordingly; it should be combined with the B20 to produce a straight bus route going direct on Pennsylvania Avenue between Starrett City and Broadway Junction, offering neighborhood residents a more convenient connection to the subway.

Third, the situation in Spring Creek is unacceptable as well. Gateway Center is a recent development, dating only to 2002, long after the last major revision of Brooklyn buses. The bus network grew haphazardly to serve it, and does so from the wrong direction, forcing riders into a circuitous route. Only residents of Starrett City have any direct route to the mall, but whereas Starrett City has 5,724 employed residents (south of Flatlands), and Spring Creek has 4,980 workers, only 26 people commute from Starrett City to Spring Creek. It’s far more important to connect Spring Creek with the rest of the city, which means buses entering it from the north, not the south. Our bus redesign proposal does that with two routes: a B6/B82 extension making this and not Starrett City the eastern anchor, and a completely redone B13 going directly north from the mall to New Lots and thence hitting Euclid Avenue on the A/C and Crescent Street on the J/Z.

What about rail expansion?

New York should be looking at subway expansion, and not just Second Avenue Subway. Is subway expansion a good solution for the travel needs of this study zone?

For our purposes, we should start with the map of the existing subway system; the colors indicate deinterlining, but otherwise the system is exactly as it is today, save for a one-stop extension of the Eastern Parkway Line from New Lots to the existing railyard.

Starrett City does not lie on or near any obvious subway expansion; any rail there has to be a tram. But Canarsie is where any L extension would go – in fact, the Canarsie Line used to go there until it was curtailed to its current terminus in 1917, as the trains ran at-grade and grade-separating them in order to run third rail was considered impractically expensive. Likewise, extending the Eastern Parkway Line through the yard to Gateway Center is a natural expansion, running on Elton Street.

Both potential extensions should be considered on a cost per rider basis. In both cases, a big question is whether they can be built elevated – neither Rockaway Parkway nor Elton is an especially wide street most of the way, about 24 or 27 meters wide with 20-meter narrows. The Gateway extension would be around 1.3 km and the Canarsie one 1.8 km to Seaview Avenue or 2.3 km to the waterfront. These should cost around $250 million and $500 million respectively underground, and somewhat less elevated – I’m tempted to say elevated extensions are half as expensive, but this far out of city center, the underground premium should be lower, especially if cut-and-cover construction is viable, which it should be; let’s call it two-thirds as expensive above-ground.

Is there enough ridership to justify such expansion?

Let’s start with Canarsie, which has 28,515 employed residents between Flatlands and the water. Those workers mostly don’t work along the L, which manages to miss all of the city’s main job centers, but the L does have good connections to lines connecting to Downtown Brooklyn (A/C), Lower Manhattan (A/C again), and Midtown (4/5/6, N/Q/R/W, F/M, A/C/E). Moreover, the density within the neighborhood is uniform, and so many of the 28,515 are not really near where the subway would go – Rockaway/Flatlands, Rockaway/Avenue L, Rockaway/Seaview, and perhaps Belt Parkway for the waterfront. Within 500 meters of Rockaway/L and Rockaway/Seaview there are only 9,602 employed residents, but then it can be expected that nearly all would use the subway.

The B42 an B17 provide a lower limit to the potential ridership of a subway extension. The subway would literally replace the B42 and its roughly 4,000 weekday riders; nearly all of the 10,000 riders of the B17 would likely switch as well. What’s more, those buses were seeing decreases in ridership even before corona due to traffic and higher wages inducing people to switch away from buses – and in 2011, despite high unemployment, those two routes combined to 18,000 weekday riders.

If that’s the market, then $500 million/18,000 weekday riders is great and should be built.

Let’s look at Gateway now. Spring Creek has 4,980 workers, but first of all, only 3,513 live in the city. Their incomes are very low – of the 3,513, only 1,030, or 29%, earned as much as $40,000/year in 2019 – which makes even circuitous mass transit more competitive with cars. There’s a notable concentration of Spring Creek workers among people living vaguely near the 3/4 trains in Brooklyn, which may be explained by the bus connections; fortunately, there’s also a concentration among people living near the proposed IBX route in both Brooklyn and Queens.

The area is the opposite of a bedroom community, unlike the other areas within the study zone – only 1,114 employed people live in it. Going one block north of Flatlands boosts this to 1,923, but a block north of Flatlands it’s plausible to walk to a station at Linden at the existing railyard. 51% of the 1,114 and 54% of the 1,923 earn at least $40,000 a year. Beyond that, it’s hard to see where neighborhood residents work – nearly 40% work in the public sector and OnTheMap’s limitations are such that many of those are deemed to be working at Brooklyn Borough Hall regardless of their actual commute destination.

There’s non-work travel to such a big shopping center, but there are grounds to discount it. It’s grown around the Shore Parkway, and it’s likely that every shopper in the area who can afford a car drives in; in Germany, with generally good off-peak frequency and colocation of retail at train stations, the modal split for public transit is lower for shopping trips than for commutes to work or school. Such trips can boost a Gateway Center subway extension but they’re likely secondary, at least in the medium run.

The work travel to the mall is thankfully on the margin of good enough to justify a subway at $50,000/daily trip, itself a marginal cost. Much depends on IBX, which would help deliver passengers to nearby subway nodes, permitting such radial extensions to get more ridership.

How Washington Should Spend $10 Billion

The planned $10 billion expansion of Washington Union Station is a waste of money, but this does not mean that money appropriated for public transportation in the National Capital Region is a waste. The region has real transportation needs that should be addressed through urban rail expansion – just not through a rebuild of the intercity rail station. Those needs include local and regional travel, to be addressed through investment in both the Metro and the commuter rail networks. It is fortunate that when I probed on Twitter, there was broad if imperfect agreement among area advocates about what to do.

A $10 billion budget should be spent predominantly on new Metro Rail lines, carefully chosen to satisfy multiple goals at once: physical expansion of the reach of the system, additional core capacity, and deinterlining to improve reliability and increase the capacity of existing lines. For the purposes of the question I posed to area advocates, I set the expansion budget at $7.5 billion, good for 30 km at average global prices, leaving the rest for commuter rail improvements.

What to do about commuter rail

Washington does not have a large legacy commuter rail network, unlike New York, Chicago, Boston, or Philadelphia. It is not as old as those cities, and its conception as the southern end of an East Coast region stretching up to Boston is postwar, by which point investment in passenger rail was largely relegated to the past. Nonetheless, it does have some lines, three to the north as the MARC system and two to the south as the VRE system. They should be upgraded to better commuter rail standards.

Union Station already has the infrastructure for through-running. The junction between the through-tunnel and the terminal tracks is flat, and almost all intercity trains terminate and most will indefinitely no matter how much investment there is in high-speed rail to points south. This requires delicate scheduling, which is good up to about 18 trains per hour in each direction, either six through- and 12 terminating or the other way around. Running half-hourly all-day service on each of the lines, with some additional urban overlay in Virginia and extra service on the Penn Line to Baltimore, should not be too difficult.

Thus, the main spending items on the agenda are not new tracks, but electrification and high platforms. MARC runs diesel trains even under catenary on the Northeast Corridor, which problem requires no additional electrification to fix, but its other two lines are unelectrified, and VRE has no electrification infrastructure. Those lines total 327 route-km of required wiring, with extensive single-tracking reducing per-km cost; this should be around $600 million. But note that they all carry significant freight traffic, and additional accommodations may be necessary.

As far as platforms go, there are nearly 50 stations requiring high platforms (I think 49 but I may have miscounted). At Boston costs it should be $1 billion or a bit more, but that’s for long trains, and MARC trains are not so long, and a system based on shorter trains at higher frequency would be somewhat cheaper. Infill stations are probably unnecessary – there are Metro Rail lines along the inner sections of most of the lines providing the urban rail layer.

Metro Rail expansion

The most pressing problem WMATA’s trains have is poor reliability. Two changes in the late 2000s and 2010s made the system worse: the 2009 elimination of automatic (though not driverless) operations worsened ride quality and reducing capacity, and the 2014 opening of the Silver Line introduced too much interlining reducing both reliability and capacity. WMATA is aware of the first problem and is working to restore ATO; the Silver Line’s problems should be fixed through judicious use of deinterlining. Deinterlining by itself only requires a short extension of the Yellow Line to separate the lines, but it can be bundled with further expansion.

Consensus among area advocates is that there should be separate tunnels for the Yellow and Blue Lines and a new trunk line under Columbia Pike, which three lines total 21 km. Additional lines can consist of another trunk line going northeast from Union Station between the Brunswick and Camden Lines or an extension of the Columbia Pike line from Bailey’s Crossroads, the present outer limit of high density, to Annandale, which would require extension transit-oriented development along the line.

A full-size version can be found here; note that the lines at Union Station are moved around to get rid of the Red Line’s awkward U-shape. The northeast extension option is colored red but should be a Blue Line extension, but the Red Line taking over H Street and going to Largo.

Systemic Investments in the New York City Subway

Subway investments can include expansion of the map of lines, for example Second Avenue Subway; proposals for such extensions are affectionately called crayon, a term from London Reconnections that hopped the Pond. But they can also include improvements that are not visible as lines on a map, and yet are visible to passengers in the form of better service: faster, more reliable, more accessible, and more frequent.

Yesterday I asked on Twitter what subway investments people think New York should get, and people mostly gave their crayons. Most people gave the same list of core lines – Second Avenue Subway Phase 2, an extension of the 2 and 5 on Nostrand, an extension of the 4 on Utica, an extension of the N and W to LaGuardia, the ongoing Interborough Express proposal, and an extension of Second Avenue Subway along 125th – but beyond that there’s wide divergence and a lot of people argue over the merits of various extensions. But then an anonymous account that began last year and has 21 followers and yet has proven extremely fluent in the New York transit advocacy conversation, named N_LaGuardia, asked a more interesting question: what non-crayon systemic investments do people think the subway needs?

On the latter question, there seems to be wide agreement among area technical advocates, and as far as I can tell the main advocacy organizations agree on most points. To the extent people gave differing answers in N_LaGuardia’s thread, it was about not thinking of everything at once, or running into the Twitter character limit.

It is unfortunate that many of these features requiring capital construction run into the usual New York problem of excessive construction costs. The same institutional mechanisms that make the region incapable of building much additional extension of the system also frustrate systemwide upgrades to station infrastructure and signaling.

Accessibility

New York has one of the world’s least accessible major metro systems, alongside London and (even worse) Paris. In contrast, Berlin, of similar age, is two-thirds accessible and planned to reach 100% soon, and the same is true of Madrid; Seoul is newer but was not built accessible and retrofits are nearly complete, with the few remaining gaps generating much outrage by people with disabilities.

Unfortunately, like most other forms of capital construction in New York, accessibility retrofits are unusually costly. The elevator retrofits from the last capital plan were $40 million per station, and the next batch is in theory $50 million, with the public-facing estimates saying $70 million with contingency; the range in the European cities with extensive accessibility (that is, not London or Paris) is entirely single-digit million. Nonetheless, this is understood to be a priority in New York and must be accelerated to improve the quality of universal design in the system.

Platform screen doors

The issue of platform screen doors (PSDs) or platform edge doors (PEDs) became salient earlier this year due to a much-publicized homicide by pushing a passenger onto a train, and the MTA eventually agreed to pilot PSDs at three stations. The benefits of PSDs are numerous, including,

  • Safety – there are tens of accident and suicide deaths every year from falling onto tracks, in addition to the aforementioned homicide.
  • Greater accessibility – people with balance problems have less to worry about from falling onto the track.
  • Capacity – PSDs take up platform space but they permit passengers to stand right next to them, and the overall effect is to reduce platform overcrowding at busy times.
  • Air cooling – at subway stations with full-height PSDs (which are rare in retrofits but I’m told exist in Seoul), it’s easier to install air conditioning for summer cooling.

The main difficulty is that PSDs require trains to stop at precise locations, to within about a meter, which requires signaling improvements (see below). Moreover, in New York, trains do not yet have consistent door placement, and the lettered lines even have different numbers of doors sometimes (4 per car but the cars can be 60′ or 75′ long) – and the heavily interlined system is such that it’s hard to segregate lines into captive fleets.

But the biggest difficulty, as with accessibility, is again the costs. In the wake of public agitation for PSDs earlier this year, the MTA released as 2019 study saying only 128 stations could be retrofitted with PSDs, at a cost of $7 billion each, or $55 million per station; in Paris, PSDs are installed on Métro lines as they are being automated, at a cost of (per Wikipedia) 4M€ per station of about half the platform length as in New York.

Signaling improvements

New York relies on ancient signaling for the subway. This leads to multiple problems: maintenance is difficult as the international suppliers no longer make the required spare parts; the signals are designed around the performance specs of generations-old trains and reduce capacity on more modern trains; the signals are confusing to drivers and therefore trains run slower than they can.

To modernize them, New York is going straight to the most advanced system available: CBTC, or communications-based train control, also known as moving-block signaling. This is already done on the L and 7 trains and is under installation on other lines, which are not isolated from the rest of the system. CBTC permits much higher peak capacity in London; in New York, unfortunately, this effect has been weaker because of other constraints, including weak electrical substation capacity and bumper tracks at the terminals of both the L and the 7.

Moreover, in New York, the L train’s performance was derated when CBTC was installed, to reduce brake wear. The effect of such computer control should be the opposite, as computers drive more precisely than humans: in Paris, the automation of Line 1 led to a speed increase of 15-20%, and CBTC even without automation has the same precision level as full automation.

As before, costs form a major barrier. I can’t give the most recent analogs, because such projects tend to bundle a lot of extras, such as new trainsets and PSDs in Paris. In Nuremberg, the first city in the world to permanently convert a preexisting metro system to driverless operations, the cost of just the driverless system is said to have been 110M€ in the late 2000s, for what I believe is 13 km of U2 (U3 was built with driverless operations in mind, and then U2, from which it branches, was converted). It is said that automating U1 should cost 100M€ for 19.5 km, but this project is not happening due to stiff competition for federal funds and therefore its real cost is uncertain. In contrast, Reinvent Albany quotes $636 million for the 7 train in New York, of which $202 million must be excluded as rolling stock conversion; the Flushing Line is 16 km long, so this is still $27 million/km and not the $7-12 million/km of Nuremberg.

Maintenance regime

The maintenance regime in New York involves heavy slowdowns and capacity restrictions. Trains run 24/7 without any breaks for regular maintenance. Instead, maintenance is done one track at a time during off-peak periods, with flagging rules that slow down trains on adjacent tracks and have gotten more onerous over the last 10-20 years; only recently have planners begun to use temporary barriers to reduce the burden of flagging.

The result of this system is threefold. First, track maintenance productivity is extremely low – the train on an adjacent track slows down as it passes but the work stops as it passes as well. Second, speeds are unreliable off-peak and the timetable is in perpetual firefighting mode. And third, parts of the system are claimed to be incapable of running more than about 16 trains per hour off-peak, which means that if there is any branching, the branches are limited to 8, which is not enough frequency on a major urban metro system.

It takes a small amount of capital spending to increase efficiency of maintenance, through procuring more advanced machinery, installing barriers between tracks, and installing crossovers at appropriate locations. But it takes a large degree of operations and management reform to get there, which is necessary for reducing the high operating costs of the subway.

Deinterlining

New York has the most complicated interlining of any global metro network. Only four lines – the 1, 6, 7, and L – run by themselves without any track sharing with other lines. The 2, 3, 4, and 5 share tracks with one another. Then the lettered trains other than the L all share tracks on various segments, without any further segregation. Only some commuter rail networks are more complex than this – and even Tokyo has greater degree of segregation between different trunk lines, despite extensive through-service to commuter rail. The New York way guarantees more direct service on more origin-destination pairs, but at low frequency and with poor speed and reliability.

London, the second most interlined system, has long wanted to reduce interlining to increase capacity. The Northern line traditionally had just one southern segment reverse-branching to two central trunks, combining and splitting into two northern branches. When CBTC opened, the busier of the central trunks got 26 peak trains per hour; the more recent Battersea extension removed the interlining to the south, permitting boosting capacity up to 32 tph, and full deinterlining to the north would boost it to 36 tph, as on the most captive Underground lines.

In New York, it is desirable to remove all reverse-branching. At DeKalb Avenue in Downtown Brooklyn, the interlocking switches the four express (bridge) tracks from an arrangement of the B and D on one track pair and the N and Q on the other to the B and Q on one track pair and the D and N on the other; the process is so complex that every train is delayed two minutes just from the operation of the switches. Everywhere within the system, interlining creates too much dependency between the different trains, so that delays on one line propagate to the others, reducing reliability, speed, and capacity.

Some of the problem is, as usual, about high costs. Rogers Avenue Junction controls the branching of the 2, 3, 4, and 5 trains in Brooklyn, transitioning from the 2 and 3 sharing one track pair and the 4 and 5 sharing another to the 3 and 4 running on dedicated tracks and the 2 and 5 sharing tracks. For a brief segment, the 2, 3 and 5 trains all share tracks. This devastates capacity on both trunk lines, which rank first and third citywide in peak crowding as of the eve of the opening of Second Avenue Subway. There are already internal designs for rebuilding the junction to avoid this problem – at a cost of $300 million.

But some of the problem is also about operating paradigms. New York must move away from the scheduling ideas of the 1920s and 30s and understand that independently-operated lines with dedicated fleets and timetables, with passengers making transfers as appropriate, are more robust and overall better for most riders. DeKalb can be deinterlined with no capital spending at all, and so can Columbus Circle. It’s Rogers and Queens Plaza where spending is ideal (but even then, not strictly required if some operational compromises are made), and the 142nd Street Junction in Harlem where an extensive rebuild is obligatory in order to permit splitting the 2 from the 5 in the Bronx permanently.

Labor changes

Staffing levels in New York are very high. Trains have conductors and not just drivers; this is not globally unheard of (Toronto and some lines in Tokyo still have conductors) but it’s rare. With good enough signaling, a retrofit even for full automation is possible, as in Nuremberg, Paris, and Singapore. Maintenance work is likewise unproductive, not because people don’t work hard, but because they work inefficiently.

Improving this situation involves changes on both sides of the ledger – staffing and service. Conductors have to be cut for efficiency and not all of them can be absorbed by other roles, and the same is true of some station facilities and maintenance functions. In contrast, the low productivity of drivers in New York – they spend around 550 hours a year driving a revenue train whereas Berlin’s drivers, who get 6 weeks of annual paid vacation, scratch 900 – is the result of poor off-peak frequency, and must be resolved through increases in off-peak service that increase efficiency without layoffs.

Ultimate goal: six-minute service

I wrote two years ago about what it would take to ensure every public transit service in New York runs every six minutes off-peak, calling it a six-minute city.

Riders Alliance argues for the same goal, with the hashtag #6minuteservice; I do not know if they were basing this on what I’d written or if it’s convergent evolution. But it’s a good design goal for timetabling, with implications for labor efficiency, maintenance efficiency, the schedule paradigm, and the bus system.

No tradeoffs

It is fortunate that the agenda of systemwide improvements does not exhibit significant tradeoffs in investment. Other parts of the transit agenda do not need to suffer to implement those improvements. On the contrary, they tend to interact positively: accessibility and PSDs can be combined (and federal law is written in such a way that PSDs void the grandfather clause permitting the subway to keep most of its stations inaccessible), faster and more reliable trains can be run more frequently off-peak, better service means higher ridership and therefore higher demand for extensions. Only the issue of labor exhibits a clear set of losers from the changes, and those can be compensated in a one-time deal.

Moreover, the budget for such an agenda is reasonable, if New York can keep its construction costs under control. At the per-elevator costs of Berlin or Madrid, New York could make its entire network wheelchair-accessible for around $3.5-4 billion. Parisian PSDs, pro-rated to the greater size of New York trains, would be around $10 million a station, or $5 billion systemwide. Full automation at German costs would be maybe $6 billion with triple- and quad-track lines pro-rated. The entire slate of changes required for full deinterlining, including a pocket track for the 3 train at 135th Street, a rebuild of the 36th Street station in Queens, and a connection between Queensboro Plaza and Queens Plaza, should be measured in the hundreds of millions, not billions.

The overall program still goes into double-digit billions; it requires a big push. But this big push is worth two to three years’ worth of current New York City Transit capital spending. A New York that can do this can also add 50-100 km to its subway network and vice versa, all while holding down operating costs to typical first-world levels. For the most part, the planners already know what needs to be done; the hard part is getting construction costs to reasonable levels so that they can do it on the current budget.

Quick Note: the LaGuardia Transit Connector

It’s amazing how much good can happen when an obstacle like Andrew Cuomo is removed. In lieu of his backward air train proposal, hated by just about everyone not on his payroll, Governor Kathy Hochul is moving forward on a better set of alternatives for a mass transit connection to LaGuardia. It’s interesting to see what the process is looking at but also what it isn’t; so far this looks better than the alternatives analysis for Interborough Express (ex-Triboro).

So far I have not seen analysis, only drawings of 14 alternatives. As with the IBX study, the LGA plan distinguishes different modes of public transit – there are bus, light rail, subway, and even ferry options. But it doesn’t stop there. It looks at multiple alignments: the scope is how to connect LGA to the rest of the city the best, and this can be done from a number of different directions – even a backward train (as light rail) along an alignment similar to Cuomo’s is present, and will likely not advance further because of its circuitous route.

Among the 14 alternatives, I think the obviously best one is a subway extension (slide 12 above); another subway option, a branch following the Grand Central Parkway (slide 11), is inferior because of branching splits frequencies and ridership at the cut off Astoria-Ditmars Boulevard station is high. A subway extension promises a connection in around 30 minutes to Times Square, every 5 minutes all day, with good connections to other destinations via the transfers at Queensboro Plaza and in Midtown.

The one thing that I’m sad the analysis hasn’t looked at is intermediate stations. It’s around 4.5 km from Ditmars to the main LGA terminal along the proposed alignment, passing through redevelopable industrial land and through residential land in Astoria Heights awkwardly tucked between airport grounds and Astoria proper. The same quality of service that the airport could get, these neighborhoods could get as well, except a hair faster because they’re closer.

Extending the Astoria Line is especially useful since it is short and not especially crowded until it hits Queensboro Plaza and inherits the crowding of the 7 train and its riders. In the context of deinterlining the subway, this is especially valuable: right now 60th Street Tunnel carries the N and W from Astoria but also the R from Queens Boulevard, and under deinterlining the tunnel would carry only Astoria riders, and so to match the high demand to 60th Street it’s valuable to create as much ridership as possible on the Astoria Line past Queensboro Plaza.

I hope that the alternatives analysis considers multiple stopping patterns in the future – that is, not just a nonstop route from Ditmars to the airport, but also an option with intermediate stations. (This does not mean local and express trains – either all trains should run locals, or all should run nonstop.) The cost of those stations is not high as it’s an elevated line, and the stop penalty on the subway is less than a minute since the top speed is so low (it looks like 45 seconds in practice comparing local and express trains on the same line).

Public Transportation in Megacities

I’ve been talking so much lately about integrated timed transfer in the context of Boston that people started asking me if it’s also applicable to New York. The answer is that the basic principles are not scale-dependent, but the implementation is, so in very large cities, public transport planning should not look like in Switzerland, a country whose largest metro area is staring at 2 million people from the bottom.

The one caveat here is that most cities are not huge. The developed world has seven megacities: Tokyo, Seoul, New York, Los Angeles, Osaka, London, Paris. And Los Angeles doesn’t really have public transportation, so we’re down to six. The middle-income world has a bunch more for sanity checking – Mexico City, São Paulo, Rio de Janeiro, Buenos Aires, Johannesburg, Moscow, Istanbul, Tehran, Beijing, Shanghai, Guangzhou, Shenzhen, Bangkok – but all are either still in convergence mode building up their networks or (mostly in Latin America) have given up. So much of this comes down to the idiosyncrasies of six cities, of which the largest three networks are substantially in the same planning tradition.

Demand is huge

Big cities have big centers, which can’t really be served by any mode except rapid transit. Even in Los Angeles, what passes for a central business district has around a 50% public transport modal split. This means that the transport network has to deliver high throughput to a relatively small city center. Even in a low-kurtosis city like Paris, most Métro lines converge on a narrow area ranging from Les Halles to Saint-Lazare; in a high-kurtosis one like New York or Tokyo, there are a few square kilometers with 200,000 jobs per km^2, which require an exceptionally dense network of rapid transit lines.

Some other network design principles follow from the need to amply serve city center. Specifically, high frequency is rarely a worry, because there’s so much demand even off-peak that usually megacity subway systems do not venture into the frequency range where long waits deter traffic; New York’s 10-minute midday gaps are bad, but that’s unusual and it comes from a combination of the legacy of postwar fear of subway crime suppressing demand and excessive branching.

But other principles require careful planning still.

Electronics before concrete, megacity version

The driverless lines in Paris support peak throughput of 42 trains per hour – a train every 85 seconds. CBTC on Line 13 without driverless operation supports 38 tph, and London’s CBTC-equipped lines support 36 tph when the branching isn’t too complex. It is imperative for other cities to learn from this and do whatever they can to reach similar headways. The difference between 21 tph, as in Shanghai, and Paris’s 42, is equivalent to building a brand new subway line. And what’s more, in a city in the size class we’re talking about, the primary concern is capacity – coverage is already good, so there really is no reason to build two 21 tph lines instead of one 42 tph one.

The situation in Paris is in a context with self-contained lines. That said, extremely busy self-contained lines do exist in other megacities – London has a bunch with near-Parisian levels of throughput, New York has some, Tokyo has a few, Seoul and Osaka are both more self-contained than Tokyo is.

Throughput and organization

The primacy of throughput means that it’s worthwhile to build small infrastructure upgrades, even with concrete, if they help with capacity. Right now the Northern line reverse-branches with the branches to the north recombining with those in the center, and Transport for London would like to split the line in two, reducing branching complexity, which would increase capacity. But doing so requires improving pedestrian circulation in the corridors of the branch point, Camden Town, where TfL expects very large transfer volumes if there’s a split and already there are circulation problems today without a split. Hence the plan in the medium term is to upgrade Camden Town and then split.

If there are bumper tracks at the end of a line, as at 8th Avenue on the L or Flushing-Main Street on the 7, then it’s useful to dig up the street for another block just to add some tail tracks. That way, trains could enter the station at full speed. This increases throughput, because the terminal interlocking has trains heading in opposite directions crossing each other at-grade, which imposes schedule constraints; it’s best if trains can go through the interlocking as fast as possible to reduce the time they’re in a constrained environment, but that in turn requires short tail tracks so that an overrun of a few meters is not catastrophic. Ideally the tail tracks should even extend a full train length past the platform to place the interlocking on the other side of it, as is done in Paris and Moscow; in that case, trains cross the interlocking out of service, when it’s easier to control their exact timings.

Such projects are disruptive, but the disruption is very localized, to just one transfer station for a deinterlining project as in London or one terminal as in New York, and the impact on capacity is very large, if not quite as large as the full suite of signaling and track upgrades that make the difference between a train every 3 minutes and a train every 1.5 minutes.

Network design

The ideal metro network is radial. Megacities already support that just because so many lines have to serve city center. However, it’s important to make sure every pair of lines intersects, with a transfer. No large metro network in the world achieves this ideal – Mexico City’s network is the largest without missed connections, but it is not radial and its only three radial lines are overburdened while the other lines have light ridership. Paris has just a single missed connection on the Métro proper, not counting the RER, but it has many pairs of lines that do not intersect at all, such as M1 and M3. London is more or less a pure radial, but there are a handful of misses, including one without any transfer between the two lines anywhere, namely the Metropolian line (including Hammersmith and City) and the Charing Cross branch of the Northern line.

Big cities that plan out a metro network have to make sure they do better. Missed connections reduce passenger ridership and lead riders to overload the lines that do get connections; for example, in Tokyo one reason cited for the high ridership of the Tozai Line is that until Fukutoshin opened it was the only one with a transfer to every other subway line, and in Shanghai, Line 1 was extremely congested as long as the alternatives going north either had critical missed connections (like Line 8) or avoided city center (like Line 3).

The role of regional rail

Regional rail as a basic concept is mostly scale-invariant. However, the design principles for trains that come every half hour are not the same as those for trains that come every 5 minutes. If trains come every half hour, they had better connect cities in a roundtrip time equal to an integer number of half hours minus turnaround times, so that they don’t have to loiter 25 minutes at a terminal collecting dust and depreciating. If they come every 5 minutes, they’re not going to loiter 25 minutes anyway, and the difference between a 5-minute turnaround and a 7-minute turnaround is not really relevant.

The design principles are then mostly about throughput, again. The most important thing is to build independent trunk lines for trains to serve city center. Even in a huge city, the finances of building a purely greenfield subway deep into suburbia are poor; Tokyo has done it with the Tsukuba Express but it’s mostly above-ground, and for the most part regional lines there and elsewhere come from taking existing suburban lines and linking them with city center tunnels.

Tokyo’s insistence on making these city center tunnels also form a coherent metro network is important. Only one non-Tokyo example is worth mentioning to add to all of this: this is Berlin, which is not a megacity but has three independent S-Bahn trunk lines. Berlin, unlike London and Paris, painstakingly made sure the S-Bahn lines would have transfers with the U-Bahn; its network has only one U-Bahn/S-Bahn missed connection, which is better than the situation in Tokyo, Paris, or (with Thameslink and Crossrail) London.

The role of development

All first-world megacities, and I believe also all megacities elsewhere, have high housing demand by domestic standards. All are very wealthy by domestic standards except Los Angeles, and Los Angeles is still incredibly expensive, it just doesn’t have the high wages to compensate that London and New York and Paris have. In such an environment, there’s no need to try to be clever with steering development to transit-oriented sites. Anywhere development is legal, developers will build, and the public transport system has a role to play in opening more land for more intense development through fast trips to the center.

A laissez-faire approach to zoning is useful in such an environment. This contrasts with smaller cities’ reliance on finger plans, like the original one in Copenhagen or the growing one in and around Berlin. No limits on development anywhere are required. The state’s planning role remains strong through transportation planning, and the suburbs may well form natural finger plans if developers are permitted to replace single-family houses with apartment buildings anywhere, since the highest-value land is near train stations. But state planning of where housing goes is counterproductive – high transit ridership comes from the impossibility of serving a large central business district by cars, and the risk of politicization and policy capture by homeowners is too great.

The advantage of this approach is also that because in a high-demand city public transport can to some extent shape and not just serve development, it’s okay to build lines that are good from the perspective of network coherence, even if the areas they serve are a bit light. This principle does not extend indefinitely – subway and regional rail lines should still go where people are – but for example building key transfer points in near-center neighborhoods that are not in high demand is fine, because demand will follow, as is building lines whose main purpose is to close some gap in the network.

Construction costs

The larger the city, the more important cost control is. This may sound counterintuitive, since larger cities have more demand – only in Manhattan could a $1.7 billion/km extension like Second Avenue Subway pencil out – but larger cities also have a bigger risk of cost blowouts. Already Tokyo has stopped building new rapid transit in the core despite very high crowding levels on the existing network, and London builds next to nothing as well. New York’s poor cost control led Philip Plotch to entitle his book about Second Avenue Subway The Last Subway. Even Paris builds mostly in the suburbs. Extensive city center and near-center construction continues in Seoul, in the context of very low construction costs.

The flip side is that a New York (or even London) that can build subways at the cost of Paris, let alone Seoul, is one that can rapidly solve all of its transport problems. My Assume Nordic Costs map fixates on a region of the world with small cities, but the construction costs in South Korea are if anything lower than in the Nordic countries. And even that map, given free reins for developers, is underbuilt – some lines would look ridiculous at current costs and zoning but reasonable given low costs and liberal zoning, for example something meandering through currently industrial parts of New Jersey.

Small cities designed their public transportation philosophy around scarcity: Switzerland really can’t just draw crayon and build it, because housing and transport demand there are finite and limited. Cities like New York and London, in contrast, should think in terms of abundance of infrastructure and housing, provided their regulations are set up in a way that permits the state to build infrastructure at low costs and private homebuilders to redevelop large swaths as they become easily accessible to city center.