Search results for: deinterlining

When Reliability Matters Above All Else

This post is about situations in which the most important thing for transportation is reliability, more so than average speed or convenience. It’s inspired by two observations, separated by a number of years: one is my own about flying into or out of Boston, the other is from a New York Times article from yesterday describing a working-class subway rider’s experience.

My observation is that over the years, I’ve used Logan Airport a number of times, sometimes choosing to connect via public transportation, which always involves a bus as the airport is not on the rail network, and other times via taxi or pickup. My choice was always influenced by idiosyncratic factors – for example, which Boston subway line my destination is on, or whether I was visiting someone with a car and free time. However, over the last eight years, a consistent trend is that I am much more likely to use the bus arriving at the airport to the city than departing. I know my own reasoning for this: the bus between South Station and the airport is less reliable than a cab, so when in a crunch, I would take a train to South Station (often from Providence) and then hail a taxi to the airport.

The New York Times article is about a work commute, leading with the following story:

Maribel Burgos barely has time to change into her uniform before she has to clock in at the McDonald’s in Lower Manhattan where she works, even though she gives herself 90 minutes to commute from her home in East Harlem.

It does not take 90 minutes to get between East Harlem and Lower Manhattan on the subway. The subway takes around half an hour between 125th Street and Bowling Green, and passengers getting on at one of the local stations farther south can expect only a few minutes longer to commute with a cross-platform change at Grand Central. Taking walking and waiting time into account, the worst case is around an hour – on average. But the subway is not particularly reliable, and people who work somewhere where being five minutes late is a firing offense have to take generous margins of error.

When is reliability the most important?

What examples can we think of in which being late even by a little bit is unacceptable? Let us list some, starting with the two motivating examples above:

  • Trips to the airport
  • Work trips for highly regimented shift work
  • Trips to school or to an external exam
  • Work trips for safety-critical work such as surgery
  • Trips to an intercity train station

In some of these cases, typically when the riders are of presumed higher social class, the system itself encourages flexibility by arranging matters so that a short delay is not catastrophic. At the airport, this involves recommendations for very early arrival, which seasoned travelers know how to ignore. At external exams, there are prior instructions of how to fill in test forms, de facto creating a margin of tolerance; schools generally do not do this and do mark down students who show up late. Doctors as far as I understand have shifts that do not begin immediately with a life-critical surgery.

But with that aside, we can come up with the following commonalities to these kinds of trips:

  • They are trips to a destination, not back home from it
  • They are trips to a fairly centralized and often relatively transit-oriented destination, such as a big workplace, with the exception of regimented shift work for retail (the original NY Times example), which pays so little nobody can afford to drive
  • They are disproportionately not peak trips, either because they are not work trips at all, or because they are work trips for work that is explicitly not 9-to-5 office work
  • They are disproportionately not CBD-bound trips

The first point means that it’s easy to miss this effect in mode choice, because people can definitely split choice between taxis and transit or between different transit modes, but usually not between cars and transit. The second means that driving is itself often unreliable, except for people who cannot afford to drive. The third means that these trips occur at a point in time in which frequency may not be very high, and the fourth means that these trips usually require transfers.

What does reliability mean?

Reliability overall means having low variance in door-to-door trip time. But for the purposes of this discussion, I want to stress again that trips to destinations that require unusual punctuality are likely to occur outside rush hour. Alas, “outside rush hour” does not mean low traffic, because midday and evening traffic in big cities is still quite bad – to take one New York example with shared lanes, the B35 steadily slows down in the first half of the day even after the morning peak is over and only speeds up to the 6 am timetable past 7 pm. Thus, there are twin problems: frequency, and traffic.

Traffic means the vagaries of surface traffic. Buses are generally inappropriate for travel that requires any measure of reliability, or else passengers have to use a large cushion. Everything about the mixed traffic bus is unreliable, from surface traffic to wait times, and bunching is endemic. Dedicated lanes improve things, but not by enough, and unreliable frequency remains a problem even on mostly segregated buses like the Silver Line to the airport in Boston.

Frequency is the harsher problem. The worker commuting from Harlem to Lower Manhattan is if anything lucky to have a straight-short one-seat ride on the 4 and 5 trains; most people who need to be on time or else are not traveling to city center and thus have to transfer. The value of an untimed transfer increases with frequency, and if every leg of the trip has routine 10-minute waits due to bunching or just low off-peak frequency guidelines, the trip gets intolerable, fast.

What’s the solution?

Bus redesigns are a big topic in the US right now, often pushed by Jarrett Walker; the latest news from Indianapolis is a resounding success, boasting 30% increase in ridership as a result of a redesign as well as other changes, including a rapid bus line. However, they only affect the issue of reliability on the margins, because they are not about reliability, but about making base frequency slightly better. New York is replete with buses and trains that run every 10-15 minutes all day, but with transfers, this is not enough. Remember that people who absolutely cannot be late need to assume they will just miss every vehicle on the trip, and maybe even wait a few minutes longer than the maximum advertised headway because of bunching.

Thus, improving reliability means a wider toolkit, including all of the following features:

  • No shared lanes in busy areas, ever – keep the mixed traffic to low-traffic extremities of the city, like Manhattan Beach.
  • Traffic signals should be designed to minimize bus travel time variance through conditional signal priority, focusing on speeding up buses that are running slow; in combination with the above point, the idea of giving a late bus with 40 passengers the same priority at an intersection as a single-occupant car should go the way of the dodo and divine rights of kings.
  • Off-peak frequency on buses and trains needs to be in the 5-8 minute range at worst.
  • Cross-platform transfers on the subway need to be timed at key transfer points, as Berlin manages routinely at Mehringdamm when it’s late and trains run every 10 minutes (not so much when they run every 5); in New York it should be a priority to deinterline and schedule a 4-way timed pulse at 53rd/7th.
  • Branch scheduling should be designed around regular gaps, rather than crowding guidelines – variation between 100% and 130% of seats occupied is less important to the worker who will be fired if late than variation between waiting 4 and waiting 8 minutes for a train.
  • Suburban transit should run on regular clockface schedules every 30, 20, or 15 minutes, with all transfers timed, including with fare-integrated commuter trains.

New York City Zoning and Subway Capacity

I got a bunch of accolades and a bunch of flaming replies over a tweetstorm imagining a bigger, better New York. Some people complained about my claim that subway trains in Brooklyn are underfull; I urge everyone to read my analysis of data from 2016 – it’s still relevant today, as the only big change is that Second Avenue Subway has reduced Upper East Side crowding. The point of this post is to demonstrate where zoning should definitely focus on adding more apartments, to fill trains that are not yet full.

The map

Instead of using the current subway map, let us start with a deinterlined map:

The reason for using this map is that it’s cleaner than the real map, since there is no track-sharing between routes of different colors, and not much route-sharing (one color local, one express). Getting from here to this map is cheap but not free, as it requires certain junction rebuilds, especially on the 2/3. I ask that my commenters resist the temptation to argue over the details of this map, since the point about zoned capacity does not really depend on questions like whether the E runs local in Queens and the F runs express or the reverse.

Where there is capacity

In 2016, three directions on the subway were truly at capacity, surpassing 4 standees per square meter: the 2/3 and 4/5 coming into Midtown from Uptown, and the L. The analysis looks at crowding on trains entering the Manhattan core, so it lumps lines from Queens based on which tunnel they enter from, which underestimates crowding on the E, since it shares tracks with the under-capacity M. Counted properly, the express Queens Boulevard trains should be viewed as near or at capacity as well, the F having 3.33 standees per square meter and the E having somewhat more.

Additional lines with capacity crunches, with about 3 standees per square meter or more, include the A/D coming in from Uptown, the 6, and the Astoria Line (then the N/Q, now the N/W). The 1 and 7 trains have capacity crunches as well in outlying areas: the 7 is overcrowded until it hits the transfer points to the E/F and N/W but has plenty of space in Long Island City, and the 1 is fairly crowded north of the junction with the express trains and then unloads passengers onto the overcrowded 2/3. These areas should not be deemed to have much spare capacity until such time as operations on the subway improve, permitting higher frequency and eventually more lines.

In contrast, the remaining lines have space, often plenty of space. Everything in Brooklyn except the L and to some extent the J/M/Z is underfull: these trains have high frequency as determined by crowding guidelines at the Uptown or Queens end, but in Brooklyn there are fewer people today so the ridership is weaker. The local lines on the Upper West Side both have plenty of space on the trains as well as space on the tracks for more trains if need be. The 7 downstream of Queensboro Plaza has plenty of space, and the local Queens Boulevard trains downstream of Jackson Heights have nowhere for passengers to transfer to an overcrowded express service.

Since I’m relying on data from 2016, there’s no accounting for Second Avenue Subway. Even then, the 4/5 was only the third most overcrowded trunk line entering the Manhattan core, and it’s likely that there’s additional capacity coming from the new line. There’s certainly space on the tracks for more trains on Second Avenue, and one of the goals of deinterlining specifically is to make it feasible to run more service on this line, which currently only runs a train every 6-8 minutes at rush hour.

The map of where New York could add housing

The map excludes parts of Lower and Midtown Manhattan where the highest and best use is commercial rather than residential. But the boundaries there are deliberately crude: Downtown Brooklyn, NYU, and the Meatpacking District are drawn, to avoid excessive fragmentation of the drawn area, while Chelsea and Hell’s Kitchen are excluded as too close to Midtown.

The map also does not look at considerations other than capacity. Some of the highlit areas on the Upper East and West Sides and Lower East Side are already built to very high density, at least on the avenues and major streets; these areas should be the template of how the rest of the city should look. At the other end, East New York has too weak demand for massive construction, especially if everything to its west is upzoned.

However, large swaths of desirable, close-in areas with relatively short buildings are highlit. Rich inner Brooklyn neighborhoods like Park Slope and South Brooklyn are currently built to missing middle density, with a floor area ratio of about 1.5 away from corner lots. A more appropriate floor area ratio in these neighborhoods is 12, corresponding to tapering buildings in the 20-30 story range, as on the avenues on the Upper East and West Sides. Park Slope is half an hour from Midtown by subway, and less than that from Lower Manhattan. The population of these neighborhoods is perhaps 150,000, and should be more than a million given their proximity to job centers.

Subway deserts and future additions

The map is designed to work with more or less the same service as today, maybe with slightly more frequency on lines that could handle it easily (that is, Second Avenue Subway). But what about future service? The L train is overcrowded, but only runs 19 trains per hour at the peak due to electrical limitations, and could go up to 26 with better electrical capacity, or for that matter lighter trains drawing less power during acceleration. Further extensions of Second Avenue Subway could more effectively relieve pressure off the 4/5, to the point of creating more capacity in the Bronx, which remains well below peak population. Commuter rail modernization opens up large swaths of Queens. Decades in the making extensions on Nostrand and Utica fill in the transit desert in southeast Brooklyn, currently served by buses that nominally come every 2 minutes and in practice comes in platoons of 4 every 8 minutes.

As with the map above, a hypothetical map of development sites assuming reasonable subway expansion includes areas that would be unlikely to actually see new development. Williamsburg and Greenpoint may turn into forests of towers given the opportunity, but in neighborhoods like Sheepshead Bay and East Flatbush developers might well stick to the occasional 6-to-10-story mid-rise building that would not look out of place in Paris. In Eastern Queens, the desired density is probably spiky, with clusters of tall buildings around LIRR stations surrounded by single-family houses and missing middle, much like the structure of density in Toronto and Vancouver.

Frequency-Ridership Spirals

I was reticent to post about this topic; I polled it on Patreon in December and it got just under 50% while the two topics I did blog, difficult urban geography and cross-platform transfers, got 64% and 50% respectively. However, between how close the vote was and the conversation about the current state of the subway in New York, I felt obligated to explain what’s been going on. The short version is that practically the entire change in subway ridership in New York over the last generation or two has come from the off-peak, and the way American cities set their frequency guidelines off-peak amplify small changes in demand, so that a minor setback can lead to collapse and a minor boost can lead to boom.

The good news is that by setting frequency to be high even if it does not look like ridership justifies it, cities can generate a virtuous cycle on the upswing and avoid a vicious one on the downswing. However, it requires the discipline to run good service even in bad times, when bean counters and budget cutters insist on retrenchment. The Chainsaw Al school of management looks appealing in recessions or when ridership is falling, and this is precisely when people who run transit agencies must resist the urge to cut frequency to levels that lead to a positive feedback loop wrecking the system.

Ridership-frequency elasticity

The key to the frequency-ridership spiral is that cutting frequency on transit makes it less useful to passengers, since door-to-door trip times are longer and less reliable. The size of this effect can be measured as the elasticity of ridership with respect to service: if increasing service provision by 1% is demonstrated to raise ridership by e%, we say that the elasticity is e.

Fortunately, this question is fundamental enough to transit that there is extensive published literature on the subject:

  • In a classical TRB paper, Armando Lago, Patrick Mayworm, and Matthew McEnroe look at data from several American cities as well as one British one, disaggregating elasticity by frequency, mode (bus or commuter rail), and period (peak or off-peak). The aggregate average value is e = 0.44 for buses and e = 0.5 for commuter rail, but when frequency is better than every 10 minutes, e = 0.22 on average.
  • Todd Litman of the advocacy organization VTPI has a summary mostly about fare elasticity but also service elasticity, suggesting e is in the 0.5-0.7 range in the short term and in the 0.7-1.1 range in the long term.
  • A paper by Joe Totten and David Levinson includes its own lit review of several studies, including the two above, finding a range of 0.3 to 1.1 across a number of papers, with the lower figures associated with urban service and the higher ones with low-frequency suburban service. The paper’s own research, focusing on transit in Minneapolis, finds that on weekdays, e = 0.39.

One factor that I have unfortunately not seen in the papers I have read is trip length. Frequency is more important for short trips than long ones. This is significant, since when the headway is shorter relative to in-vehicle trip time we should expect lower elasticity with respect to the headway. Waiting 10 minutes rather than 5 minutes for an hour-long trip is not much of an imposition; waiting 30 minutes rather than 15 for the same trip is a greater imposition, as is waiting 10 minutes rather than 5 for a 20-minute trip.

In New York, the average unlinked subway trip is 13.5 minutes long, so the difference between 10 and 5 minutes is very large. Lago-Mayworm-McEnroe cite research saying passengers’ disutility for out-of-vehicle time is 2-3 times as large as for in-vehicle time; the MTA’s own ridership screen states that this penalty is 1.75, the MBTA’s states that it is 2.25, and a study by Coen Teulings, Ioulina Ossokina, and Henri de Groot says that it is 2 in the Netherlands. Figuring that this penalty is 2, the worst-case scenario for off-peak weekday wait time in New York, 10 minutes, has passengers spending more perceived time waiting for the train than riding it, and even in the average case, 10/2 = 5 minutes, it is close. In that case, higher values of e are defensible. Lago-Mayworm-McEnroe have less data about in-vehicle time elasticity and do not attempt to aggregate in- and out-of-vehicle time. But adding everything together is consistent with e = 0.8 relative to speed averaged over the total wait and in-vehicle time, and then e is maybe 0.4 relative to frequency.

The impact of service cuts

If the elasticity of ridership relative to frequency is 0.4, then cutting service by 1% means cutting ridership by 0.4%. If half the operating costs are covered by fares, then revenue drops by 0.2% of total operating expenses, so the 1% cut only saves 0.8% of the total subsidy. Achieving a 1% cut in operating costs net of fare revenue thus requires a 1.25% cut in service, which reduces ridership by 0.5%.

This may not sound too bad, but that’s because the above analysis does not incorporate fixed costs. Rail comes equipped with fixed costs for maintenance, station staffing, rolling stock, and administration, regardless of how much service the agency runs. Lisa Schweitzer uses this fact to defend Los Angeles’s MTA from my charge of high operating costs: she notes that Los Angeles runs much less service than my comparison cases in the US and Europe and thus average cost per train-km is higher even without undue inefficiency. In contrast, bus costs are dominated by driver wages, which are not fixed.

New York does not keep a headcount of transit employees in a searchable format – the Manhattan Institute’s See Through New York applet helps somewhat but is designed around shaming workers who make a lot of money through overtime rather than around figuring out how many people work (say) maintenance. But Chicago does, and we can use its numbers to estimate the fixed and variable costs of running the L.

The CTA has somewhat more than 10,000 workers, split fairly evenly between bus and rail. The rail workers include about 800 working for the director of maintenance, working on the rolling stock, which needs regular servicing and inspections regardless of how often it’s run; 550 working for facilities maintenance; (say) 400 out of 800 workers in administrative capacity like communications, general counsel, purchasing, and the chief engineer’s office; 600 workers in power and way maintenance; nearly 1,000 customer service agents; and 450 workers in flagging, switching, and the control towers. Only 500 workers drive trains, called rapid transit operators or extra board, and there may charitably be another 200 clerks, managers, and work train operators whose jobs can be cut if there is a service cut. A service cut would only affect 15% of the workers, maybe 20% if some rolling stock maintenance work can be cut.

In New York the corresponding percentage is somewhat higher than 15% since trains have conductors. Train operators and conductors together are about 13% of the NYCT headcount, so maybe 20% of subway employees, or 25% with some extra avoidable maintenance work.

What this means is that achieving a 2% cut in subsidy through reducing service requires a service cut of much more than 2%. If only 25% of workers are affected then, even without any frequency-ridership elasticity, the agency needs to cut service by 8% to cut operating costs by 2%.

The Uber effect

The combination of elasticity and fixed costs means that rail ridership responds wildly to small shocks to ridership. For a start, if the agency cuts service by 1%, then operating costs fall by 0.25%. Ridership falls by 0.4%, and thus revenue also falls by 0.4%, which is 0.2% of total operating costs. Thus operating costs net of revenue only fall by 0.05%. The only saving grace is that this is 0.05% of total operating costs; since by assumption fare revenue covers half of operating costs, this saves a full 0.1% of the public subsidy.

Read the above paragraph again: taking fixed costs and elasticity into account, cutting service by 1% only reduces the public subsidy to rail service by 0.1%. A 2% cut in subsidy in a recession requires a brutal 20% cut in service, cutting ridership by 8%. And this only works because New York overstaffs its trains by a factor of 2, so that it’s plausible that 25% of employees can be furloughed in a service cut; using Chicago numbers this proportion is at most 20%, in which case revenue falls one-to-one with operating costs and there is no way to reduce the public subsidy to rail operations through service cuts.

Of course, this has a positive side: a large increase in service only requires a modest increase in the public subsidy. Moreover, if trains have the operating costs of Chicago, which are near the low end in the developed world, then the combined impact of fixed costs and elasticity is such that the public subsidy to rapid transit does not depend on frequency, and thus the agency could costlessly increase service.

This is relevant to the Uber effect – namely, the research arguing that the introduction of ride-hailing apps, i.e. Uber and Lyft, reduces transit ridership. I was skeptical of Bruce Schaller’s study to that effect since it came out two years ago, since the observed reduction in transit ridership in New York in 2016 was a large multiple of the increase in total taxi and ride-hailing traffic once one concentrated on the off-peak and weekends, when the latter rose the most.

But if small shocks to ridership are magnified by the frequency-ridership spiral, then the discrepancy is accounted for. If a shock cuts ridership by 1%, which could be slower trains, service disruptions due to maintenance, or the Uber effect, then revenue falls 1% and the subsidy has to rise 1% to compensate. To cover the subsidy through service cuts requires a 10% cut in service, further cutting ridership by 4%.

Off-peak service guidelines

The above analysis is sobering enough. However, it assumes that service cuts and increases are uniformly distributed throughout the day. This is not the actual case for American transit agency practice, which is to concentrate both cuts and increases in the off-peak.

Unfortunately, cuts in off-peak service rather than at rush hour do not touch semi-fixed labor costs. The number of employees required to run service is governed by the peak, so running a lot of peak service without off-peak service leads to awkward shift scheduling and poor crew utilization. Higher ratios of peak to base frequency correlate with lower total service-hours per train driver: in addition to the examples I cite in a post from 2016, I have data for Berlin, where the U-Bahn’s peak-to-base ratio is close to 1, and there are 829 annual service-hours per driver.

I discussed the fact that the marginal cost of adding peak service is several times that of adding off-peak service in a post from last year. However, even if we take rolling stock acquisition as a given, perhaps funded by a separate capital plan, marginal crew costs are noticeably higher at the peak than off-peak.

In New York, the rule is that off-peak subway frequency is set so that at the most crowded point of each route, the average train will be filled to 125% seated capacity; before the round of service cuts in 2010 this was set at 100%, so the service cut amounted to reducing frequency by 20%. The only backstop to a vicious cycle is that the minimum frequency on weekdays is set at 10 minutes; on weekends I have heard both 10 and 12 minutes as the minimum, and late at night there is a uniform 20-minute frequency regardless of crowding.

Peak frequency is governed by peak crowding levels as well, but much higher crowding than 125% is permitted. However, the busiest lines are more crowded than the guidelines and run as frequently as there is capacity for more trains, so there is no feedback loop there between ridership and service.

The saving grace is that revenue is less sensitive to off-peak ridership, since passengers who get monthly passes for their rush hour trips ride for free off-peak. However, this factor requires there to be substantial enough season pass discounts so that even rush hour-only riders would use them. Berlin, where U-Bahn tickets cost €2.25 apiece in bundles of 4 and monthly passes cost €81, is such a city: 18 roundtrips per month are enough to justify a monthly. New York is not: with a pay-per-ride bonus a single ride costs $2.62 whereas a 30-day pass costs $121, so 23.1 roundtrips per month are required, so the breakeven point requires a roundtrip every weekday and every other weekend.

New York subway ridership evolution

The subway’s crisis in the 1970s reduced ridership to less than 1 billion, a level not seen since 1918. This was on the heels of a steady reduction in ridership over the 1950s and 60s, caused by suburbanization. In 1991, ridership was down to 930 million, but the subsequent increase in reliability and fall in crime led to a 24-year rally to a peak of 1,760 million in 2015.

Throughout this period, there was no increase in peak crowding. On the contrary. Look at the 1989 Hub Bound Report: total subway ridership entering Manhattan south of 60th Street between 7 and 10 am averaged about 1 million, down from 1.1 million in 1971 – and per the 2016 report, the 2015 peak was only 922,000. Between 1989 and 2015, NYCT actually opened a new route into Manhattan, connecting the 63rd Street Tunnel to the Queens Boulevard Line; moreover, a preexisting route, the Manhattan Bridge, had been reduced from four tracks to two in 1986 and went back to four tracks in 2004.

Nor was there much of an increase in mode share. The metropolitan statistical area’s transit mode share for work trips rose from 27% in 2000 to 30% in 2010. In the city proper it rose from 52% in 1990 to 57% in 2016. No: more than 100% of the increase in New York subway ridership between 1991 and 2015 was outside the peak commute hours, and nearly 100% of it involved non-work trips. These trips are especially affected by the frequency-ridership spiral, since frequency is lower then, and thus a mild positive shock coming from better maintenance, a lower crime rate, and perhaps other factors translated to a doubling in total ridership, and a tripling of off-peak ridership. Conversely, today, a very small negative shock is magnified to a minor crisis, even if ridership remains well above the levels of the 1990s.

The way out

Managers like peak trains. Peak trains are full, so there’s no perception of wasting service on people who don’t use it. Managers also like peak trains because they themselves are likelier to ride them: they work normal business hours, and are rich enough to afford cars. That current NYCT head Andy Byford does not own a car and uses the city’s transit network to get around scandalizes some of the longstanding senior managers, who don’t use their own system. Thus, the instinct of the typical manager is to save money by pinching pennies on off-peak service.

In contrast, the best practice is to run more service where possible. In Berlin, nearly all U-Bahn trains run every 5 minutes flat; a few lines get 4-minute peak service, and a few outer ends and branches only get half-service, a train every 10 minutes. At such high frequency, the frequency-ridership spiral is less relevant: an increase to a train every 4 minutes would require increasing service by 25%, raising costs by around 5% (Berlin’s one-person crews are comparable to Chicago’s, not New York’s), but not result in a significant increase in ridership as the shorter headway is such a minute proportion of total travel time. However, New York’s 10-minute off-peak frequency is so low that there is room to significantly increase ridership purely by running more service.

In 2015 I criticized the frequency guidelines in New York on the grounds of branching: a complexly branched system must run interlined services at the same frequency, even if one branch of a trunk line is somewhat busier than the other. However, the frequency-ridership spiral adds another reason to discard the current frequency guidelines. All branches in New York should run at worst every 6 minutes during the daytime, yielding 3-minute frequency on most trunks, and the schedules should be designed to avoid conflicts at junctions; non-branching trunk lines, that is the 1, 6, 7, and L trains, should run more frequently, ideally no more than every 4 minutes, the lower figure than in Berlin following from the fact that the 1 and 6 trains are both local and mostly serve short trips.

Moreover, the frequency should be fixed by a repeating schedule, which should be clockface at least on the A train, where the outer branches would only get 12-minute frequency. If ridership increases by a little, trains should be a little more crowded, and if it decreases by a little, they should be a little less crowded. Some revision of schedules based on demand may be warranted but only in the long run, never in the short run. Ideally the system should aim at 5-minute frequency on every route, but as the N, R, and W share tracks, this would require some deinterlining in order to move more service to Second Avenue.

This increase in frequency is not possible if politicians and senior managers respond to every problem by cutting service while dragging their feet about increasing service when ridership increases. It requires proactive leadership, interested in increasing public transit usage rather than in avoiding scandal. But the actual monetary expense required for such frequency is not large, since large increases in frequency, especially in the off-peak, mostly pay for themselves through extra ridership. The initial outlay required to turn the vicious cycle into a virtuous one is not large; all that is required is interest from the people in charge of American transit systems.

New York City Subway Expansion Proposal

I wrote a post proposing disentangling the subway in New York a few months ago. On the same basis, I’ve drawn some extra lines that I think should be built in the event the region can get its construction costs under control:

A higher-resolution image (warning: 52 MB) can be found here. The background image is taken from OpenStreetMap. Python 2.7 code for automatically downloading tiles and pasting them into a single image can be found here. Make sure you get PIL or else the paste.py file won’t run; first run tiles.py, and choose whichever tiles you’d like (the boundaries I used for this image are given in the paste.py code as x1, x2, y1, y2), and then run paste.py, changing the x1, x2, y1, y2 variables in the code as needed. As a warning, pasting images together makes them much bigger – the sum of the individual tiles I used is 15 MB but pasted together they became 46 MB.

Legend

Local stations are denoted by black circles, express stations by bigger circles with white filling. On four-track lines and three-track lines with peak-direction express trains (that is, the 2, 6, and D in the Bronx and the 7 in Queens), the local/express designation is straightforward. Two-track tails are denoted as all local; for the most part the trains continue as express on the three- or four-track lines, but on the Brighton Line the expresses keep turning at Brighton Beach while the locals are the trains that go into Coney Island. On a few two-track segments stations are denotes as express and not local, for example the 2 in Harlem or the A in Lower Manhattan and Downtown Brooklyn: this occurs when a two-track line turns into a three- or four-track line farther out, so that people don’t get the impression that these are local-only stations that the express trains skip.

The local and express patterns are barely changed from today. On Eastern Parkway trains run local east of Franklin Avenue, without skipping Nostrand and Kingston-Throop as the 4 does today. Skip-stop on the J train is eliminated, as is express-running between Myrtle and Marcy Avenues. On Queens Boulevard and Central Park West, the trains serving Sixth Avenue (i.e. the orange ones) run express and the ones serving Eighth (i.e. the blue ones) run local, but I’m willing to change my mind on at least one of these two designations; on Queens Boulevard, 36th Street is also turned into an express station, so that passengers can transfer to 63rd or 53rd Street.

As far as possible, I’ve tried to be clear about which stations are connected and which aren’t. The rule is that circles that touch or are connected by a black line denote transfer stations. However, in the lower-resolution version it may hinge on a single pixel’s worth of separation in Downtown Manhattan. The only new interchanges in Downtown Manhattan connect the 1 with PATH in the Village and at World Trade Center (and the latter connection also connects to the R, E, and 2/3).

No existing subway station is slated for closure. If an existing subway station is missing a circle, it’s an error on my part. Edit: I found one mistaken deletion – the 9th Street PATH station (which should be connected with West 4th, but the West 4th circle doesn’t touch PATH).

New lines

Most of this map should be familiar to people who have followed discussions among railfans in New York (and not just myself) about the next priorities after Second Avenue Subway. Utica and Nostrand are there, with stops that match nearly all of the east-west buses. Northern Boulevard, which Yonah Freemark pointed is a denser corridor than Utica, is also there. Triboro RX is there: the route through the Bronx includes a little more tunneling to connect with the 2 train better, forced by incursions onto the right-of-way farther north. LaGuardia gets an elevated extension of the N, which I’ve periodically argued is superior to other alignments and sound in its own right. Second Avenue Subway continues west under 125th Street, providing crosstown service on a street where buses are very busy despite being slower than walking.

In New Jersey, a hefty proportion of the lines already exist, as part of PATH or the Hudson-Bergen Light Rail. PATH is completely dismembered in this proposal: the line from Newark to World Trade Center is connected with the 6 train, an idea that I don’t think is a top priority but that some area advocates (such as IRUM) have proposed; most of the rest is turned into a 7 extension and connected with the two southern HBLR branches, both of which are extended, one to Staten Island and one to Newark; what remains is reduced to a shuttle from Hoboken to Sixth Avenue. Note that the 6-PATH train also gets an infill stop at Manhattan Transfer for regional rail connections.

The other extensions come from a number of different places:

  • The 6 is extended to Co-op City, the 7 is extended to College Point, and the 1 to the edge of the city. The first two are big ridership generators, and all three also extend lines beyond their bumper tracks, increasing turnback capacity.
  • The Queens Boulevard express trains branch in Jamaica, as they do today, and both branches are extended to near city limits. The southern extension also increases turnback capacity (some E trains run to Jamaica-179th and not Jamaica Center today for this reason), but the primary purpose is to improve coverage to areas of the city that are already at worst missing middle density and redevelopable as mid-rise apartment blocks, and have very long commutes today.
  • The 1 is extended to Red Hook. This was proposed by AECOM a few years ago; my alignment differs somewhat in that it doesn’t connect Red Hook with the subway within Brooklyn, but does connect it directly with South Brooklyn, where in the event of such a subway extension a high-frequency bus (the B71) could run onward.
  • Instead of the periodically mooted 7 extension to Secaucus, the L is extended there, with a four-track tunnel under the Hudson providing for easy 7/L transfers.
  • There’s a preexisting bellmouth for connecting the C train to New Jersey across the George Washington Bridge; it is activated in this plan, with an extension to Paterson elevated over Route 4, with tunneling within Paterson itself. Route 4 is a freeway, but it’s flanked by shopping centers in Paramus, has good regional rail connections and good potential connections if the Northern Branch and West Shore Line are reactivated, and terminates in a dense working-class city.
  • The old Erie Main Line gets converted to subway operations, running elevated through the built-up area of Secaucus.
  • To connect some of the new lines to one another, two new Manhattan trunk lines, both two-track, are built: under 50th Street, and under Third Avenue, the latter substituting for phases 3 and 4 of Second Avenue Subway in order to avoid reverse-branching. Third then connects to the northern reaches of Eighth Avenue Line via a super-express line, with new stations at 110th and 125th; the alignment through Central Park is designed to allow cheap cut-and-cover construction.
  • Bergenline Avenue, where traffic fills a bus every 2 minutes, gets a subway. One station is designed for a commuter rail transfer to new Hudson tunnels with a Bergenline stop. The segment south of Journal Square is weaker and can be removed from scope, but as it can be done in an existing above-ground right-of-way, it’s also cheaper than the rest.
  • The D train gets a two-stop extension to the north to connect to Metro-North at Williams Bridge and the 2 train at Gun Hill Road.

Conspicuous absences

There is no subway connection to JFK or Newark Airport on this map. The JFK AirTrain is adequate with better regional rail and fare integration; so is a Newark connection at the current commuter rail station. A direct JFK regional rail connection may be included in a 9-line regional rail map (for reference, the map I usually peddle has 5 or 6 trunk lines, not 9). A Newark rapid transit connection may be included in a much more expansive version, but even then it’s unlikely – the only reason to build such a connection is for extra capacity, and it’s better to resolve mainline rail capacity crunches by building more mainline rail.

There is no R train to Staten Island, an extension that some railfans (including myself many years ago) periodically call for; this could be added, but is a low priority, as regional rail could provide faster service to Downtown Brooklyn with a transfer than the R train ever could.

But the biggest absence is Second Avenue Subway phases 3 and 4. Phase 3 is replaced with a subway under Third Avenue, and phase 4 is omitted entirely. The reason for this omission is, as mentioned above, to avoid reverse-branching, and permit the new system to consist of separate lines without track-sharing, which is more reliable than today’s heavily interlined system.

Phase 4 is also difficult and not all that useful. Lower Manhattan construction is sometimes necessary but should be avoided when it isn’t, as the area has narrow rights-of-way, complex underground station footprints, and archeology going back to the 17th century. There is no capacity crunch heading to Lower Manhattan – southbound trains unload in Midtown in the morning peak – and the area is so small and has so many subways that there is no coverage gap that Second Avenue Subway would fill. Even phase 3 mostly duplicates the Lexington Avenue Line, but serves a large and growing business district in East Midtown where trains do have a capacity crunch, hence the Third Avenue subway.

Scope and costs

The map has around 110 km of new subway and 100 km of new els and other open-air lines (such as the Triboro and Erie rights-of-way). Some of the subways can be built cut-and-cover given sufficient political cajoling, including Nostrand, most of Bergenline, parts of Third and Utica, Northern, and the outer Queens extension. But many cannot: there are 6 new river crossings (50th*2, 7, L, Utica, 1), a kilometer of pure pain in connecting the 6 with PATH, another PATH pain involving a new Exchange Place dig for platforms for the 7, and some new stations that have to be mined (e.g. 50th Street).

At what I consider a normal first-world cost, the tunnels would be around $25 billion in last decade’s money, so maybe $30 billion in today’s money, and the els would add around $10 billion. To put things in perspective, the current five-year MTA capital program is spending $33 billion, nearly all of which is routine maintenance. It’s affordable within a decade if the region gets its construction costs under control.

Reverse-Branching Does not Save You the Transfer

I wrote a detailed proposal about why New York should deinterline, and how. I got a lot of supportive comments (in the transit blogging sense, i.e. nitpicking), but also some pushback, arguing that people like their one-seat rides, and making them transfer under a more coherent system would make their riding experience worse. I could go on about how London is facing the same problem and is choosing to invest a lot of money into deinterlining in order to increase train capacity, but in the case of New York, there’s a blunter answer: what one-seat ride? The extent of reverse-branching on the subway does not really give people one-seat rides, and New York City Transit is making service decisions that do not maximize one-seat rides even when doing so would be relatively painless.

Outer branches

Most outer branches with just one route naturally offer direct service to the route’s trunk line. Let’s look at the current subway_map, and compare it with my proposed deinterlining, which is again this:

Today, riders on the West End Line only have service on the D, so they only have a one-seat ride to Sixth Avenue. Riders on the Sea Beach Line only have the N, and riders on the local Brighton Line trains only have the Q, so they only have one-seat rides to the Broadway express trains, and if they want to travel to Prince Street or 8th Street-NYU on the R they have to change trains at Canal, which is not a cross-platform transfer. Only a handful of stations get genuine choice between the two trunk lines: 36th Street on the D and N, and the inner few express stops on the B and Q, say up to Newkirk Avenue. These are express stops, with more ridership than the locals, but they’re not the majority of ridership on the subway in Southern Brooklyn. The majority of riders have to deal with the drawbacks of both reverse-branching (slow, infrequent trains) and coherent service (fewer one-seat rides).

Queens Boulevard has the same situation: local and express patterns mix up in a way that makes the choice of one-seat rides much weaker than it appears on the map. Riders at the local stations can choose between the M and the R, two trains that are never more than a few blocks apart in Midtown; only one station on either line is inconvenient to access from the other, 57th Street/7th Avenue, the least busy stop on the Broadway Line in Midtown on a passengers per platform basis (49th and 5th have less ridership but have two platform tracks and no Q service). The express stops get more serious choice, between the E and F, but those are just three stations: Jackson Heights-Roosevelt Avenue, Forest Hills-71st Avenue, and Kew Gardens-Union Turnpike. Queens Plaza has E, M, and R service, but passengers actually getting on at Queens Plaza can equally get on at Queensboro Plaza and ride the N, W, or 7.

Genuine choice between two relatively widely-separated trunk lines on the same trunk only exists in two and a half places in New York: the Central Park West Line offers a choice between the B and C trains, the Nostrand Avenue Line offers a choice between the 2 and 5 trains, and the inner half of the White Plains Line offers a choice between the 2 and 5 trains off-peak (at the peak the 5 runs express, so local stations only get the 2).

Cross-platform transfers

New York is blessed with cross-platform interchanges, usually between local and express trains on the same line. Riders on the 1 train are used to transferring to the 2 and 3 trains cross-platform at 96th Street; in the morning, the 1 train’s busiest point is actually from 103th Street to 96th, and not heading into Midtown. With 170,000 boardings at its stations north of 96th per weekday, the 1 is much busier than Nostrand (with 60,000 weekday boardings) or the combined total of local Central Park West stations from 72nd to 116th (with 65,000 boardings). It’s also slightly busier than the White Plains Road Line, let alone the inner segment with both 2 and 5 service (which has 95,000 boardings).

In Queens, a similar situation occurs on the 7. The stations east of Queensboro Plaza, excluding 74th Street-Broadway (where the transfer to the Queens Boulevard Line is), have a total of 215,000 weekday boardings. The trains fill at the outer end and then discharge at 74th Street as most passengers transfer, not cross-platform, to the faster Queens Boulevard Line; then they fill again at the stations to the west and discharge at Queensboro Plaza, which has a cross-platform transfer to the N and W.

This is relevant to some of the few segments of the subway where reverse-branching offers choice between different trunk lines. Passengers on the Nostrand Avenue Line could transfer cross-platform at Franklin Avenue, where the platforms aren’t much narrower than at 96th Street and Broadway, where passenger volumes are almost three times as high. Similarly, passengers on the Central Park West Line and its branches to Washington Heights and Grand Concourse could transfer cross-platform at 125th Street or at Columbus Circle; Columbus Circle is extremely busy already with origin-and-destination traffic, and the interchanges between local and express passengers could not possibly overwhelm it.

Only one place has a difficult connection: 149th Street-Grand Concourse, the interchange between the 2, 4, and 5 trains. This also happens to be the most difficult deinterlining project in general, because of the merger of the 2 and 3 further south; it requires either closing the northernmost two stations on the 3, or opening up a few blocks of Lenox Avenue to construct a pocket track. Because of the disruption involved, this project can be left for last, and come equipped with more passageways at 149th Street, just as London is first deinterlining the Northern line to the south (raising peak capacity on the Bank branch from 26 trains per hour to 32) and leaving the north for later (which would raise capacity further to 36 tph).

NYCT has deinterlined in the past

Upper Manhattan witnessed two deinterlinings in the second half of the 20th century, one in the 1950s and another in the 1990s. The service NYCT inherited from its three predecessor networks had systematic route nomenclature taking into account conventional and reverse branching.

On the IRT, West Side trains were numbered 1 (to Van Cortlandt Park), 2 (to the White Plains Road Line), and 3 (to Harlem-148th Street), and Lexington trains were numbered 4 (to the Jerome Avenue Line), 5 (to the White Plains Road Line), and 6 (to the Pelham Line); 2, 4, and 5 trains ran express, 3 and 6 trains ran local, and 1 trains could be either local or express. In the 1950s, NYCT changed this system on the West Side so that all 1 trains became local and all 3 trains became express. This was the result of track layout: the junction at 96th Street is flat if 3 trains have to cross over to the local tracks and 1 trains have to cross over to the express tracks, but under today’s present service pattern there are no at-grade conflicts. NYCT chose capacity and reliability over offering one-seat rides from West Harlem and Washington Heights to the express tracks.

On the IND, trains were identified by letters. A, C, and E trains ran on Eighth Avenue and B, D, and F trains on Sixth Avenue; A and B trains went to Washington Heights, C and D trains to Grand Concourse, and E and F trains to the Queens Boulevard Line. Local and express trains were identified using letter doubling: a single letter denoted an express train, a doubled one (e.g. AA) a local. The single vs. double letter system ended up discontinued as few trains consistently run express (just the A and D) and several run a combination of local and express (the B, E, F, N, and Q), and NYCT slowly consolidated the trains on Eighth and Sixth Avenue until there were only seven services between them. Eventually the B and C switched northern terminals, so that now the C runs as the local version of the A and the B as something like the local version of the D. Passengers in Washington Heights who wish to use Sixth Avenue Line have to transfer.

The situation on the IND wasn’t as clean as the deinterlining on the IRT. But it shows two important things. First, changes in train service have made the original reverse-branching less tenable from an operational perspective. And second, the value of a one-seat ride from Washington Heights or Central Harlem to local tracks is limited, since everyone takes the express train and transfers at Columbus Circle.