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.


  1. Henry

    I agree with most of the deinterlining except that of the J/M/Z. The M and J/Z have wildly different travel paths, and of the two the M is far more popular, since it goes to where people actually want it to go. Delancey Essex is not a good transfer point, and neither are Canal or Fulton since those would require backtracking, to say nothing of their actual physical facilities. Of all the merges that are most likely to cause cascading delays throughout the system, the J/M/Z has very limited impact.

    • newtonmarunner

      I disagree with you. I think Culver should get full service to 6th Ave. (which provides a decent East New York/Coney Island off-peak connection from a lower transfer penalty), and LES, which has pretty crummy transit service for Manhattan and their distance to the CBD, should get full service on the F and J. Further, if we send the G to Atlantic (to relieve the A and give the G better connections to BMT/IRT Lines), Park Slope/Red Hook/Williamsburg on off-peak retain decent connections to each other.

      • newtonmarunner

        As for improving the J, eliminate skip-stop service and improve the connection to the G at Broadway so the J transfers to the G rather than the L.

        • newtonmarunner

          My plans have Culver going 20-30 tph to 6th Local; Fulton to 8th Express (to CPW Express) at 30-35 tph. Off-peak service is 50 to 75 percent of those figures. Coney Island and East New York will never have a 1-seat ride to each other any more than UES and UWS will have a 1-seat ride to each other.

          My concern is the transfer penalty at Jay St./Metrotech from A/C to F for East NY to Coney Island (and vice versa) during off-peak hours if you give Culver only a branch worth of service — rather than a full trunk. 8-10 minute headways on weekends (current service) is a huge transfer penalty compared to 4-5 minute headways (de-interlined service). Travel between these two communities, I think, is enough that riders shouldn’t be facing those kinds of off-peak transfer penalties.

      • Henry

        The F provides a rather circuitous ENY – Manhattan connection, and I can’t really believe that ENY – CI travel demand is all that high.

        The 6th Av M is important in that it provides a relatively attractive alternative to the overburdened L since it’s a one-seat ride to Midtown.

        I’m a little bit perplexed as to what a G to Atlantic would even look like, and why that would be better than just digging out a passageway connecting Lafayette G and Fulton C to Atlantic.

        These numbers are a bit dated, but there is no capacity crunch on the F. There also isn’t on the J/M/Z, but that line has seen a much more dramatic growth trajectory due to the gentrification of Northern Brooklyn, and I would not be surprised if post-L shutdown, at least some L ridership switched over to the M permanently.

        • Alon Levy

          The L runs 20 tph on infrastructure that can handle 26. The problem there is electronics rather than concrete; unfortunately, even electronics cost a fortune in New York, but they’re investing in the required upgrades as we speak. I didn’t list this as an extension opened up by deinterlining because it’s a separate issue, but I would propose extensions of both the L and the 7 to avoid dealing with bumper tracks: the 7 should be extended a few stops to College Point, partly in an open cut, and the L should be extended one stop into the Meatpacking District, and this way both lines could run 30+ tph with CBTC.

          The G to Atlantic would be a small dig costing a large fortune. I brought it up semi-seriously on Twitter; some people decided it was a great idea, some decided it was terrible. I’m mostly in the terrible camp, for the reason you give – it’s way easier to build pedestrian passageways to the C and G.

          • newtonmarunner

            I’d add that you could probably squeeze out a few more tph on Flushing, too, if you eliminate peak direction express service. That, however, might further congest 74th/Roosevelt as more Flushing travelers would want the QB Express, its difficult transfer notwithstanding.

            [Fwiw, I still think based on matching line-tunnel demand, Flushing should get 59th St. Bridge and Astoria should get the 42nd St. Tunnel. But that would not be easy to do for the operating cost savings and one-seat Flushing-Chinatown ride.]

          • Alon Levy

            The limiting factor on the 7 is the bumper tracks at Flushing. There are 3 of them, but they’re still bumper tracks. It’s not the local/express system.

          • adirondacker12800

            Trains stopped running over the 59th Street Bridge in the 40s when they tore down the Second Ave El.

          • adirondacker12800

            I’m not in the mood to go check all of schedules for all of the buses that go to Flushing. If you are going to extend the 7 either extend it east, where the busiest bus lines are or south where the busiest bus line are. People can change to the train outside of downtown Flushing. The buses will still go to downtown but some of the transferring will move out of downtown.

          • Henry

            They are *partially* addressing the issue; IIRC the L shutdown will only include upgrades to bump by 1-2 TPH. That being said, the most logical L terminus is Hudson Yard, probably with an intermediate stop at 23rd. (And eventually a northern extension to 72 to relieve the West Side IRT.)

          • newtonmarunner

            I agree with you that the bumper tracks are the biggest limiting factor to the Flushing Line’s capacity. Still, getting rid of express/local will add 1-3 tph at no cost.

          • newtonmarunner

            @airodancker — Extending the 42nd St. Subway West to Hoboken/Jersey City isn’t a bad idea. But (1) it’s costly, and more important (2) it doesn’t solve the capacity problem on the Flushing Line. I like Flushing going to (1) College Point or down (2) Main St. to Jamaica Transit Center, though (1) is probably preferable to (2).

          • adirondacker12800

            I didn’t say anything about New Jersey. I think extending the subway to New Jersey is a realllllllly stupid idea.

          • newtonmarunner

            @airodonacker — Couldn’t disagree more on extending the subway to NJ being a stupid idea. Extending the subway to NJ would (1) make 42nd St. demand less unidirectional, so minimal operating costs, (2) prevent much of Hudson and Union Counties from having 3-seat rides to Manhattan jobs, and (3) increase political support from NJ for the Garden State to get EMUs for regional rail.

            Extending the subway to Bergenline Ave. — eventually — is definitely sensible, IMO (though not with 42nd St.).

          • adirondacker12800

            Eastern Hudson County is a long narrow peninsula with a ridge running down the middle. Except for the few people who live within walking distance of the station, they would trading their one seat ride, to the PABT and walk, or two seat ride, bus to the PABT and change to the subway, for a three seat ride. Get the suburbanites who go down to the train station, where there are trains, to get on a bus to the PABT, onto a train, that leaves more capacity in the tunnel and the PABT for frequent buses in Hudson County.

        • newtonmarunner

          Sorry, @Henry. My response on the East New York-Coney Island 2-seat ride is above your reply. Much like UES-UWS, ENY and CI will never have 1-seat rides to each other. It’s the off-peak transfer penalty @ Jay St/MetroTech (as well as not giving full service to LES on 6th Local and Nassau St.) for ENY to CI (A/C to F) that bothers me if you keep J/M/Z together rather than giving full service from Culver to 6th Local (and full service on Nassau St.).

    • Eric

      “and neither are Canal or Fulton since those would require backtracking”

      A transfer at Canal only backtracks by about 300m. That adds less than a minute of total travel time – insignificant.

      • Henry

        That’s also assuming the transfer at Canal to any trains is straightforward, which would be a generous characterization of that general complex. A minute of transfer time, plus whatever additional transfer time, would be pretty awful.

        • Eric

          Still much preferable to waiting 10 minutes for another M train, or whatever people do nowadays.

          • Henry

            There’s a fair amount of leeway with how much M service can be run. They plan to run trains every 4 minutes during the L shutdown; presumably, if they bought enough cars and Bombardier had not screwed up delivery of the new trains, they would be able to run such services even in normal conditions.

            Quite frankly, the orange M is the best thing to have happened to transit riders on that line in decades.

  2. johndmuller

    Many or the problems you attempt to fix with uninterlining are imperfections in the network, such as lack of flyovers at Rogers Jct, W96th St and the Lenox turnouts. Adding those flyovers would ‘fix’ the IRT pretty well, provided the dispatching and switching crews were trained by il duce’s transit engineers. [To top it off, you could add/replace the junction on the Jerome Ave line north of Yankee Stadium, crossing into Manhattan and turning south to join the Lenox fork; some improvement to the existing transfer options to the west side from Jerome.]

    The timers are also playing havoc with the dynamics of optimizing one’s trips. It used to be, at least in my memory, that express trains went faster than they seem to now. For example, the run down Central Pk. West now features an express cruising sedately down the outer track while a local stops and zooms through all those stations staying more or less even with the express; in my recollection, one had a good chance of gaining a local by switching to an express at certain strategic points (if you were desperate to get somewhere or just a kid playing on the subway).
    The same spoilers seem to have done the job to other lines as well somebody has reined in the expresses.

    In Brooklyn, they have flat out removed the expresses from many lines, turning the trips from the outer reaches into excuses for driving. Need to jazz up the expresses so that some of the outer branches can be extended further out and still be reasonable. In the case of Brooklyn, it probably needs to wait for the SAS so that there is somewhere for the expresses to go; there would seem to be space in the Montague and Rogers St, tunnels if there was an SAS or something else on the Manhattan side.

    • Alon Levy

      Yes, the timers are a big part of the problem on the express lines, which is why I’m only ascribing 2 minutes of delay to the junction. The Q does DeKalb-Canal in 8 minutes on the schedule; it should be about 4 at 70 km/h, 5 at 50 km/h (which might be compatible with the timers), and 6 at 40 km/h (which definitely is compatible). But delays at the merge point are still serious, which is why the N and Q’s average speed over the bridge is low even by the standards of other long nonstop runs subject to timers, like 125th-59th or QBP-Lex.

      What you’re proposing with junction fixes is hard. In the 1950s NYCT chose not to do it but instead deinterline; at the time it was still rebuilding parts of the system, e.g. adding express platforms at 59th and Lex. Building new flying junctions is extremely expensive, and has no real purpose on the West Side Line except saving a transfer on a very frequent line for people on the 1.

  3. Bobbo

    What is the train-per-hour loss for local stops in the peak direction in the Bronx and Queens on three-track lines? I often take the 6 to Westchester Sq. in the evenings and, especially counting the almost inevitable 3-5-minute wait at Parkchester for the local to pull out and switch to the downtown tracks. I often wonder if I’ve even saved any time and, even if I have, if it’s worth the loss of service to the local trains.

    • Alon Levy

      The stop penalty is about 45-60 seconds, but in practice it’s less because express trains tend to have longer dwell times. The time difference per the schedule is 5-6 minutes between Parkchester and 125th Street.

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