Why is Second Avenue Subway Phase 2 So Expensive?

I am only loosely following the news about the second phase of Second Avenue Subway. The project, running from 96th Street to 125th, with a short segment under 125th to Lexington, passing under the 4, 5, and 6 trains, is supposed to be cheap. In the 1970s, work began on Second Avenue Subway before the city went bankrupt, and there are extant tunnel segments built cut-and-cover in East Harlem between the station sites. The stations need to be dug, but the plan dating back to 2003 was to build them cut-and-cover as well, with local disruption for only a few blocks around 106th, 116th, and 125th Streets. Only one part would be difficult: going deep under 125th, under the preexisting subway. And yet, costs are very high, and the design seems to be taking a wrong turn.

In the early 2000s, the cost projections were $3.7 billion for phase 1 (actual cost: $5 billion, but much of the difference is inflation), and $3.3 billion for phase 2 (projected cost: at least $6 billion). Since then, there have been changes. For about a year I heard rumors that the preliminary engineering had been done wrong, and it was impossible to use the preexisting tunnel segments. Then I heard that no, it’s actually possible to use the existing tunnels. But a few days ago I heard that even though it’s possible, the MTA is now planning to demolish the existing tunnels and build the entire project deep underground using tunnel-boring machines.

With the information generally given out at community meetings, it’s hard to know what’s exactly going on. However, the fact that the MTA is talking about this suggests extreme disinterest in cost control. Cut-and-cover construction is cheaper than TBMs, per a 1994 paper by Godard, Barrié, Zhang, et al, looking at French urban rail costs since the 1970s. The tradeoff is that it forces rail lines to go underneath streets, which is disruptive to pedestrians and merchants, or demolish private property. Fortunately, Second Avenue is a wide, straight throughfare, and requires no such demolitions, while the disruption would be localized to areas that are scheduled to get subway stops as part of the project. Metro extensions here and in a number of other European cities are constructing stations cut-and-cover and the tunnels between them with TBMs; Metro Line 12’s online documents state that station construction involves just 18 months of digging.

It’s possible that the need to turn to 125th Street is messing up the plan to do everything cut-and-cover. While the turn itself can be done with minimal demolitions (the inside of the curve has a few small buildings, and there’s also an alignment slightly farther east that goes under vacant land while maintaining a 90-meter curve radius), going underneath the Lexington Avenue Line requires diving deep, and then there is no advantage to cut-and-cover. Building cut-and-cover under existing lines is difficult, and in that case, TBMs are warranted.

If the problem is 125th Street, then I would propose extending phase 2 and then breaking it apart into two subphases. Phase 2.0 would be cut-and-cover and open stations at 106th, 116th, and possibly 125th and 2nd temporarily. Phase 2.5 would involve driving TBMs under 125th Street all the way to Broadway; this could be done with a large-diameter TBM, with the platforms contained within the bore and vertical access dug so as to avoid the intersecting north-south subways. 125th Street has 30,000 crosstown bus boardings according to the MTA, which would make it the busiest bus corridor in the city per km: 10,000 per km, compared with 8,000 on the busiest single route, the M86. It is a priority for subway expansion, and if it’s for some reason not possible to easily build from 96th and 2nd to 125th and Lex in one go then the entire project should be extended to 125th and Broadway, at somewhat higher cost and far higher benefits.

The reason phase 1 was so expensive is that the stations were mined from small digs, rather than built cut-and-cover as is more usual. The idea was to limit street disruption; instead there was street disruption lasting 5 years rather than 1.5, just at small bore sites at 72nd and 86th rather than throughout the station boxes’ footprints. The TBM drive and systems cost together $260 million per kilometer, compared with $125 million on Paris’s Metro Line 1 extension, but the stations cost $750 million each, compared with $110 million.

It’s crucial that the MTA not repeat this mistake in phase 2, and it’s crucial that area transit activists hold the MTA’s feet to the fire and demand sharp cost control. Even taking the existing premiums as a given, cut-and-cover stations should not cost more than $200 million each, which means phase 2 as planned should cost $600 million for stations, about $330 million for systems, and another $350 million for overheads. At $1.3 billion this still represents high cost per kilometer, about $500 million, but it’s based on actual New York cost items, which means it’s plausible today. There is no excuse for $6 billion.


  1. Ian Mitchell

    Obviously, a 2nd ave subway and a crosstown line under 125th street are warranted, but do they actually need to belong to the same project?

    I’d rather see a crosstown line under 125th street link as part of Triboro RX than as a dogleg off the the 2nd ave subway. Would there be insurmountable depth issues?

    • newtonmarunner

      I disagree. A 2nd-125th subway means

      (1) a 2-seat ride for NW Harlem/Inwood/Washington Hts. to UES
      (2) a 2-seat ride for East Harlem/UES to West 4th.
      (3) a non-Times Sq. 2-seat ride going from UWS to UES and vice versa (effectively relieving 2/3 at 72nd St.).

      Also, having Triboro go through the Hub (albeit on the edge) rather than 125th means the Grand Concourse Line and 6 have a 2-seat rail ride to the Bronx Hub. This would effectively relieve the Bx1/2 buses.

      I’m also not feeling the Harlem/Bronx ties to (74th/Roosevelt) Jackson Heights (or Queens’s ties to Harlem). I think a lot more people in the Bronx work in LIC/Williamsburg/Downtown Brooklyn or a secondary job cluster in Manhattan (e.g., Union Sq./W. 4th/Columbia) than work on 74th/Roosevelt. Improving those kinds of commutes should take higher priority, IMO.

      • Ian Mitchell

        “This would effectively relieve the Bx1/2 buses.”
        I’m not so sure I agree.

        As far as commuting patterns, I’d rather defer to the data.

      • adirondacker12800

        They already have a two seat ride from the Upper East Side to West 4th. Change at 63rd and Lex to the F. Across the platform.
        Triboro, any proposal I’ve seen, uses existing railroad ROW. There isn’t any at 74th and Roosevelt that isn’t already subway.

        • newtonmarunner

          E. Harlem doesn’t have an easy 2-seat ride to West 4th. It’s a looong walk from 51/Lex (6) to the E on 53rd/3rd.

          Triboro connects to 74th/Roosevelt. Might be a tough transfer, though.

        • adirondacker12800

          Take the Q train to 63rd and Lex, cross the platform to the F, the F goes to West 4th street. Unless I’m grossly misunderstanding. Nah, uptown Lex to 125th to change to a downtown Q doesn’t get West 4th. Uptown Lex to 125th to change to the Q for West Side lines, I assume the IND, to get to West 4th, would be a three seat ride. Musta had something in mind that involves changing to the IND at 125th and St. Nicholas from,a Second Ave. train from a Second Ave. station. The E train doesn’t go that far uptown, it goes to Queens. If I was possessed of the urge to take an uptown Second Avenue train to 125th and St. Nicholas to get West 4th I’d take an A or a D not a B or a C. Unless there is something going on or the dead of night, crossing the platform at 63rd and Lex would be easier and faster. The F train goes to West 4th, it’s across the platform at 63rd and Lex.

          • Alon Levy

            From the Upper East Side or East Harlem to West 4th the fastest way is to take the 6 to 8th-NYU or the 4/5 to Union Square and then walk. The 6/E transfer sucks, and the Q/F transfer is okay but both legs of the trip have shit off-peak frequency.

          • newtonmarunner

            I smell someone’s de-interlining plan being necessary to improve frequency and reliability and decrease transfer penalties. …

  2. marvin gruza

    The 125 Street aspect of the 2nd avenue subway is expensive and will either kill the project or kill all subsequent pieces. Extend the 2nd ave subway into the bronx and/or maybe into Queens.

    For 125th Street, a segregated bus lane or light rail (maybe even continued over the triboro bridge to LGA) would give a better combination of service and bang for the $

  3. vanshnookenraggen

    A bigger picture problem is that there is no big picture planning going on at the MTA or city. 2nd Ave will be terminated at 125th because no one has bothered to think about where else it could go. Planning for this started 20 years ago and much has changed, especially in the Bronx. Cross-125th is obvious but nothing is being done about the Bronx. The original reasoning behind 2nd Ave (1929) was that it would convert the 6 train from a long local to 2nd Ave express. This obviously cannot happen today but this is due to lack of any planning going on. Replacing the 6 with the Q is a non starter, not to mention the Q wouldn’t be enough service for a new 3rd Ave (Bronx) line. Connecting it to the Concourse Line will cause problems and has questionable demand since the 4 is already there. The only simple option I can see is to extend the Q along the MetroNorth tracks to 180th St and have it replace the Eastchester 5 since. But nothing is going to be perfect because 2nd Ave was botched from the start. Not to mention if Phase 3 will ever happen.

    • adirondacker12800

      The Metro North tracks are full of Metro North trains. More less next to a cliff that give people to the east longer walks and people to the west… still on existing lines that aren’t at the bottom of a cliff.

        • Alon Levy

          I suspect going under 125th does a lot more to relieve crowding on the 2/3 than taking over the NYWB. It’s probably even on time with the 2/3 to Times Square even while making more stops, just because the 2/3 is so slow, and it’s definitely faster for jobs in the 50s or if you’re going from Park or 5th to Times Square.

          (Also, I killed your duplicate comment.)

          • vanshnookenraggen

            Thanks! I totally see the usefulness of 125th in the grand scheme. My rant was more about how since no one is doing long range planning 2nd Ave is being built to be far less useful than it could be.

          • newtonmarunner

            Still, how many trains per hour is the 2/3 running uptown during rush hour? 22? It seems to me they should try to get that figure up to 30+ before laying concrete requiring deep tunnel boring.

          • newtonmarunner

            I just don’t see how 2nd Ave. can be more useful than going across 125th. I don’t like going up 3rd Ave. because (1) the one branch under a river rule (2) we already have wasted Metro North capacity on the Harlem Line, and (3) the Grand Concourse and Jerome Ave. Lines won’t be able to transfer in the Bronx or Harlem (in the case of Jerome, it’d be a difficult transfer) to the Q and vice versa. Heck, there should be a transferring on a branch rule that it doesn’t count as a good transfer since the penalty is so much higher from lower frequency.

    • red dog

      If 125th is such a major concern and issue and possible expense, it seems like somewhere along the line someone should try to figure out where all the present bus riders, who everyone thinks will just move underground, are going and coming from. I’m always surprised that many planners base their plans on what makes sense to them, and not to the actual ridership is doing and would like to do.

  4. Henry

    125/Park has always struck me as an awful terminal. I don’t know that 125th would actually do all that well as a subway corridor; most bus riders on 125th St are heading to other destinations on 125th St, and in that case the depth of a crosstown subway could potentially make travel time vs. a bus not all that much faster. After all, the M14A/D are still extremely busy despite the presence of the L underground, and the 7 is not used by people traveling within 42 St. Add in the fact that it forecloses the possibility of two extensions to the Bronx (one serving Third, one serving Castle Hill/Soundview/Hunts Point to relieve the 6) and I dislike the general idea.

    If it were up to me, Phase I would go to 116/2nd, and Phase II would go up Third in the Bronx to 149th, to link to the Eastern Bronx lines before the Lex (and thus actually provide some measure of time-competitiveness with the Lex versus a transfer that forces you to get on the Lex anyways)

    • vanshnookenraggen

      You make a good point about surface transit needs vs subway but I would argue that there is still a solid percentage of riders on 14th St who take the L from the west to the east sides and the 7 also has the parallel Shuttle which is heavily used during the day. It’s worth considering a 125th crosstown line which goes to Queens instead but either way you have to deal with digging deep and subway to surface travel times is more of an issue here than at 14th or 42nd Sts where the subways are not as deep. Again, lack of long term planning will end up costing more in the long run because ideas like this can’t be dealt with now.

    • chris

      To add to vanshnookenraggen’s notes, the M14s goes further west, and have stops further east on 14th.

      The 7 also has limited utility for 42nd street riders, given that it only has three stops. If the 10th Ave stop was built, I imagine it would be a lot more popular.

    • Alon Levy

      I don’t think the Bronx needs that much relief. Here is the ridership per tail in the Bronx (the 3 transfer stations add another 45,000). The stations from 68th to 125th inclusive have 238,000 weekday riders, as of 2016. The trains in the Bronx just aren’t that crowded – the crowding starts in Harlem.

      The Bronx could use extensions that add coverage, rather than relief. But that’s where Metro-North comes in – Park Avenue lies right between Grand Concourse and White Plains Road.

      I don’t expect people to take a 125th Street crosstown one stop, and even two stops may be dicey. But trips all the way from Broadway to the East Side are plausible, as are trips involving a transfer, such as from Washington Heights to the UES or from the Bronx to Columbia. The curve from 2nd to 125th here is a feature and not a bug: it gives people from West Harlem and Washington Heights a direct two-seat ride to Uptown Manhattan’s second biggest job center.

      • newtonmarunner

        I think the Bx1/2, Bx15, Bx19, and Bx41 need relief (and wealthy Morrisania and East Tremont by the Murphy Triangle need rail coverage) as much of their demand is unidirectional. Also, there should probably be at least two radial trunk lines going to 3rd/149th (the Hub), with the second radial connecting to the 6 at 138th or 125th.

          • newtonmarunner

            Grand Concourse Line has $hit connections to the Bronx Hub and the 6. That — and the rapid transit desert on the northern parts of the Bx1/2 probably why the bus route’s ridership is so high. But you’re right — the priority should be the places missed by the Harlem Line’s Regional Rail on 3rd Ave, Murphy Triangle, and East Tremont, and a stronger connection for the 6 to the Bronx Hub.

      • crazytrainmatt

        Not sure what the ridership numbers correspond to on the ground, but as of a few years ago, rush hour 4 trains would be packed well before entering Manhattan.

      • Henry

        Bronx -> UWS is already served by the 1/2/B/D, and none of those are at capacity north of 96 St.
        Other connections from 125th headed downtown from SAS are not competitive going Downtown; going to the UES/Midtown, the 4/5 head directly there, the 2 has a direct transfer to the 4, the B/D also have a connection to the 4 and are only a few blocks away. That basically leaves you ridership on the 1, A/C, the Manhattan portions of the 2/3, and the 6 if you want to put up with the slightly higher inconvenience of SAS over the Lex express. Which is not a lot.

        Third is certainly worthy of a train; B/D and 2/5 together have 220,000 riders, the Bx41 and Bx15 add another 51,000. So assuming that half the people taking B/D and 2/5 can be served by Third, that’s 161,000 potential riders. (In reality this figure is probably higher since the 4 is so close to the B/D and is almost certainly siphoning away riders from those lines.)

        Plus according to New York’s investigation into SBS expansion, Third Av/Soundview, as the last frontiers of affordability within the five boroughs, are high-growth areas that are served by inconvenient bus trips to overcrowded subway lines. Lex trains are actually crowded south of Yankee Stadium; 125th is overcrowded not because of Harlem, but because it’s the northernmost transfer point between the 4/5 and 6. Encouraging more people to transfer at 125/Park-Lex would make overcrowding worse; better to make the SAS stop at Third/138th and Third/149th after 116th, to provide a much faster intercept for 2/5 and 6 riders. (As far as 125th/2nd goes, I think it’s a pretty crap location to put a subway station; the river flood zone + the MTA bus depots + Triboro onramps make it a place with very limited walkshed and sustainable development potential.)

  5. johndmuller

    For the sake of getting something done in some of our lifetimes perhaps instead of terminating at Lex on 125th, with portals to the future northern extension, it should rather build to a temporary terminal at (or just north of) 125th on 2nd, with portals to furn before 125th for the future 125 St. branch. If the ultimate build-out should end up with both the 125th and Lex as well as the 125 and 2nd stations, it wouldn’t be the end of the world – could even be some kind of transfer point for healthy living through walking types. I don’t believe many people will bother to get off the Lex at 125th to transfer onto the Q or T once they’ve already gotten onto it; except for 6 train riders, if they wanted to go to Times Square they most likely already had a chance take or to transfer to the 5. As for MN riders transferring there instead of GCT, yeah sure (and yes, I know that there are some trips where transferring to the Q might be a good idea, but Penn Station access for both sides of MN might exist before this transfer does).

    Except for figuring out the proper depths for the portals to 125th St. and the 2nd & 125th station so as not to be too shallow for the follow on segments, this construction would be less complicated with all the stuff involving the underpinnings beneath the Lex and MNRR (and whatever future-proofing might need to be done to accommodate increasing MN’s track load should they wish to build up or down in their corridor). So conceivably, much of this phase could be built with cut and cover except insofar as the northern part might need to be deeper to anticipate their future paths.

    Putting off the 125th segment might be bad politically, so maybe not the ideal approach, but maybe splitting off a branch before getting into the Bronx is not the way to go either. Should have built a 4 track mainline in phase 1; perhaps it is time to think about ways to deal with that shortcoming.

    • newtonmarunner

      I think Regional Rail from Grand Central Station to Fulton St. via Union Sq. will take care of not 4-tracking SAS. Waaay cheaper than tunneling under the Harlem River, also hits more compelling destinations in Union Sq. and Fulton St. than the ones in SAS Phases III and IV.

      Also, trying to get 30+ tph on SAS to Broadway, 53rd St to 8th Ave, CPW Express, 7th Express, 8th Express, Lex Express, etc. will help. Organization before electronics before concrete.

      • johndmuller

        Hard to see how tunneling under the Harlem River would be more expensive than MN breaking out of GCT southbound (let alone Waaay more), finessing the way through the Shuttle, 7 and Lex morass (possibly having to shift some of their tracks a bit). If you’re gonna build deep stations under the 3 and 4 line junctions at Union Sq and Fulton St, your now talking about a lot more tunneling in Manhattan versus the Bronx and two stations which will each be more complicated than the 3rd/138th and 3rd/149th transfer stations between SAS and the 6 and 2,5 lines would be in the Bronx.

        One interesting thing to do south of GCT might be to rebuild the Lex under Lexington Ave, giving over the Park Ave ROW to MN down to Union Square. The new Lex would go down through Gramercy Pk then beneath Irving to its own 14th St stop, possibly overlapping the L‘s 3rd Ave station enough for a transfer, then plow ahead to rejoin the Lex trackage before Astor Pl. Possibly split the Lex express off from the local in this section and give only the express tracks to MN, keeping all the local stations in use. Remember I said interesting, not financially or logistically feasible.

        • newtonmarunner

          Except SAS Phases III and IV aren’t thaaat useful compared to Regional Rail to Fulton via Union Sq. GCT, Union Sq., and Fulton St. (1) are more compelling destinations than 2nd or 3rd Ave. south of Midtown, and (2) connect to other lines (2/3/4/5/6/7/L/N/Q/R/W/A/C/J/Z) in a way 2nd Ave. Subway Phases III and IV don’t, and (3) has greater capacity than the subway as trains are longer.

          2nd Ave. is much better going to 125th St. than 3rd Ave. in the Bronx, which is wasting capacity. We don’t have an unlimited supply of track or unlimited space underground.

      • Eric

        “I think Regional Rail from Grand Central Station to Fulton St. via Union Sq. will take care of not 4-tracking SAS. ”

        Why not both? It would allow for a lot more upzoning.

        • newtonmarunner

          In the longer term, I think both will be necessary. I’d just rather start with RR to Fulton than 4-tracking SAS. The legacy tracks on the Harlem Line to GCT are virtually free, and Union Sq. and Fulton St. are more compelling destinations than SAS Phases III and IV are origins. RR would really help those on the Harlem Line get to Midtown Southeast, Penn, FiDi, Downtown Brooklyn, Newark (though not a popular destination for 3rd Ave and the rest of the Harlem Line), Union Sq. a lot faster.

  6. marvin gruza

    Maybe the region should think big and overcome state line divide.
    1-Send 15 tph from 2nd Ave across 125 Street to 8th ave and then up 8th ave to and over the GW Bridge into NJ (NJ routing and transfer options would be numerous and the fare in NJ would be distance based with swiping /tapping required both on entry and exit)
    2-use the rest of the GW capacity for the local 8th Ave service that currently terminate at 168 Street.

    3-Sent the rest of the 2nd Ave train up to Coop City via the existing RR right of way
    4-use the rest of of the 125 capacity (extended to 125th Street Hudson Ferry transfer) for the 6 TPh Trioborox + 6TPH for a LGA>citifield>Jamaica>JFK service (yes jamaica would require either a reverse move or a loop)
    5-send the 6TPH of the TriboroX + 6TPH of the LGA link also to coop City

    *Northern Nj/southern Rockland are served directly or indirectly with pressure removed from the PABT and Penn Station allowing for smaller/cheaper replacements to be built
    *Bronx/coop city is served
    *ridership is diverted of the Lex IRT
    *TrioboroX and a LGA/JFK line have transfers to every subway trunk line + the park ave and westside MetroNorth + a Hudson River ferry system
    *Regional connectivity is enhanced
    There may be enough for everyone for this to be politically doable

    • Alon Levy

      Two problems:

      1. This involves complex branching, connecting SAS, Eighth Avenue Line, Triboro, and the new branches. This means low service reliability because delays on one line propagate to the others, and this in turn constrains capacity.

      2. There’s no real demand for travel from SAS up St. Nick. The local tracks on St. Nick are underused because there’s not a lot of demand for slow travel, and SAS offers a circuitous service to Midtown and couldn’t compete. Meanwhile, a connection up St. Nick would divert trains away from 125th/Broadway, near Columbia, the biggest job center in Manhattan north of Midtown.

    • adirondacker12800

      The primary problem is that they went and used the capacity on George Washington Bridge for more road lanes back in the 60s. There’s no cheap ROW on the New Jersey side and there aren’t a lot of people in Bergen and Rockland counties that want to get to 178th Street are additional problems. Especially since many of them already have a more direct, faster route to Midtown and Downtown.

      • Eric

        They should take some of those lanes away and use them for the subway. There is cheap ROW in the median of the freeway. This might even decrease freeway congestion, since the subway can carry many times more people than a lane of cars. But of course I’m preaching to the choir here…

  7. Comradefrana

    “The reason phase 1 was so expensive is that the stations were mined from small digs, rather than built cut-and-cover as is more usual.”

    Well, 2/3 of them were (half if you count 63rd st/Lex). 96th street station was constructed cut-and-cover and still managed to cost $800 million. Of course, there was additional scope some of which would probably not be necessary for the phase 2 stations. As I understand it the important items were: base slab of the bored tunnel from 87th to 92nd streets; retrofit of the existing 99th-105th street tunnel (technically not part of the station, would be necessary for the phase 2 existing tunnels anyway); concrete slab and street restoration for the TBM Launchbox/track cross-over area, excavation itself being part of the tunneling contract (although excavating and building a track cross-over area would be necessary for a potential 116th st/125th st terminus).

    pages 24 and 42

    “Even taking the existing premiums as a given, cut-and-cover stations should not cost more than $200 million each”

    Unfortunately, I believe that is way too optimistic. Given existing premiums, you would need almost twice as much just for excavating the station (96th Street Station Heavy Civil, Structural and Utility Relocation contract alone costed $397 million).

  8. The Economist

    If there is no plans to extend the line across 125 street, why are they making the station below the 4/5/6? Stub-end the line as a shallow surface line east of the the existing 4/5/6 station and make the new station 4 track station.

    Pros: much, much cheaper (no underpinning 4/5/6 or Metro-North), all cut-and-cover construction, full use of the preexisting shallow tunnels, build two shallow stations along 2nd Avenue (the originally planned ones from way back when) instead of one in the middle of the preexisting shallow tunnel segment that requires demolishing that preexisting segment, nothing precludes extending the line as a shallow line towards the Bronx (well, it will not be that shallow under the river, but you know what I mean)

    Cons: no tail tracks cuts your throughput, but the larger number of station tracks should allow for reasonable frequencies on both the Q and the T (the station tracks might need to be on two levels with two tracks each to avoid at least some movement conflicts, but it is still a shallow station!) , no extension to the west ever (but that is the premise under which I am proposing this).

    See, we cannot get everything, and if all we will be getting is a stub station anyway, we could at least build it cheaply. The only way to build it cheaper than this is to not build anything at all.

    • The Economist

      Just ignore me :-). I should have looked at the map first. There is not enough space for a stubbed end station east of Lexington given the location of the curve. this might have worked for a line going up 1st Avenue.

  9. Eric

    SAS Phase 1 is basically a local subway. This suggests that Phase 2 should also be a local, and the best local route is under 125th to Broadway.

    What about an express SAS line? That should not be interlined with the local. The NYC subway has too much interlining already, and this would make it worse. Rather, a NEW tunnel should be build under 2nd Ave (or maybe 1st or 3rd Ave). This new tunnel will be the express line, including SAS segments 3 and 4. In the Upper East side, its only stop will be at 86th St, with transfer to the local. It will have another stop at 125th St, then continue to the Bronx (I suggest under 3rd Ave in the Bronx, then taking over the Dyre Ave branch).

    • newtonmarunner

      There is so much unused tracks on the Harlem Line that I’d rather start with regional rail — even if it isn’t as nice as a subway, which has hits more stops in the CBD, and has easier transfers.

      I have changed my mind on Dyre Ave and White Plains getting a full trunk. The capacity problem isn’t thaaat far out. Alon once told me that suburbs should get branches and no more. Applying this to NYC, outer boroughs on express subway lines should get branches and no more (fully local lines should get the full trunk to the CBD and w/o reverse branch).

      Instead of taking over Dyre Ave, if you put 3rd Ave on an express line, I say hit the Murphy Triangle and another stop on Tremont between the RR stop and West Farms Sq. But do de-interlining and 5-Line RR first.

      • adirondacker12800

        Not in the Bronx there isn’t. Those pesky New Haven Line trains use it too.

        • newtonmarunner

          There’s enough floor space such that with integrated fare zoning and 48 trains per hour that the trains are no more crowded than the 2/3 from 125th to GCT.

          There are four tracks on the Harlem Line. That’s enough for at least 2×24, or 48, trains per hour. Running anything less is wasting capacity.

          • adirondacker12800

            Terminating some of them in Mott Haven so Hudson Line trains can go to Manhattan isn’t particular useful.

          • newtonmarunner

            Who said anything about terminating trains in Mott Haven? Trains under Alon’s 5-Line RR plan would run through GCT to either to Fulton St. (or South Ferry) via Union Sq. (and Fulton St.) or New Jersey via Penn/Secaucus Junction. They’d be crowded, though.

          • adirondacker12800

            Ya can’t run 48 trains an hour through Woodlawn and still run trains through Highbridge.

          • newtonmarunner

            Sorry, 36 tph on Harlem/New Haven. That’s still 12 tph on the Harlem Line (which has no branches) and 24 tph on the New Haven Line (which has 4 branches, and doesn’t branch until late going outbound). I don’t think MNR currently runs thaaat much service.

          • Alon Levy

            Metro-North runs 16 peak tph on the Harlem Line today, and my suspicion is that it has more suppressed demand than any other NY-area commuter line, because it passes through the Bronx and Mount Vernon. My assumption in the regional rail proposal is that it gets 24 tph even with New Haven Line trains stopping at Wakefield and Fordham.

          • adirondacker12800

            Where do the trains go in Manhattan? And I’m sure you know how to set up the spreadsheet that will tell you how many trains an hour they need in 2040 with 1 percent growth per year, 2 percent a year etc. The fantasies of using Metro North tracks through the Bronx for local service are fantasies. The tracks are already being used.

          • Alon Levy

            There’s growth in the city and not in Westchester, which is not permitting any housing growth. And the tracks today are well-used, but there’s still far more space per passenger than on the subway.

          • adirondacker12800

            In nice round numbers the population of Westchester County has gone up ten percent since Metro North was formed.


            ….”Metro-North’s total ridership has more than doubled since the railroad was founded in 1983.”

            All that new housing in the Bronx isn’t going to be on Webster Ave. either.

            Add a million people to the city running a few more trains isn’t gonna cut it.

          • Alon Levy

            Metro-North claims 80% mode share on peak-hour Manhattan-bound commutes, so there’s nowhere for peak ridership to go unless there’s population growth.

          • marvin gruza

            the best way to increase capacity is to divert a portion current Grand Central trains to and through Penn Station to Nj (yes through running service) via new river crossings.

          • crazytrainmatt

            Metro North might be “near” capacity doing business as usual, but anecdotally it seems they are nowhere near it even without sending trains to Penn. Local trains on the Harlem line are only 6-8 cars. The 5th seat (in the 3+2 seating config) is a waste — people only squeeze in there at the times when more aisle space would be a huge help. The crawl from 60th St into Grand Central must absolutely trash the capacity of the Park Ave tunnel (in addition to disproportionately lowering the value for short rides). But I’ve got to imagine that removing tracks and junctions from Grand Central would speed up the approach. Grade separating the wye with the Hudson line or lengthening platforms costs orders of magnitude less then a new tracks in the Bronx.

          • newtonmarunner

            Huh? Harlem runs 16 tph? Bronxville, Scarsdale, and Chappaqua get sub-4:00 headways?

            My assumption was Hudson/Highbridge gets 12 tph (which it shares with Harlem), Harlem gets 12 tph on the Harlem Local in the Bronx, and New Haven Lines get 24 tph (spread equally among the branches) on the Harlem Express in the Bronx. What’s your RR scheduling permutation look like? Thanks.

          • Alon Levy

            Right now the schedule is 16 tph at the peak with a mixture of local and express trains.

            What I think they should run is:

            Hudson: 6 tph local to Yonkers via Grand Central, 6 tph local to Croton-Harmon via the Empire Connection, 6 tph express to Poughkeepsie via the Empire Connection
            Harlem: 24 tph local to North White Plains, half (arguably one third or one quarter) continuing to Southeast, 1-2 tph continuing to Wassaic
            New Haven: 6 tph local to Stamford via Hell Gate, 6 tph local to Stamford via Grand Central, 12 tph express beyond Stamford of which 3 go to New Canaan, 3 to Danbury, and 6 to New Haven

            All of this is at the peak. Off-peak, pick your favorite number between 1 and 2 and make that your peak-to-base ratio. It reverse-branches a bit, but the infrastructure reverse-branches and there’s nothing that can be done short of closing service from the Hudson Line to the West Bronx and Grand Central.

          • adirondacker12800

            The lower middle class family cashes out when their back office jobs in White Plains or Tarrytown moves to Scranton or Utica or goes virtual to be replaced by someone who fills one of those new cubes in Manhattan. Who paid extra because the house that was by the noisy tracks in 1985 is now “walk to train”.

          • johndmuller

            I get that it is anathema to some that people from Connecticut and Westchester usually get a seat (and sometimes a nice view) on their way to GCT while the hoi polloi get to stand and sweat on the IRT. So do they wonder why it is that NYC has such a high transit mode share compared to other parts of the US? Perhaps part of it is that in addition to the cattle cars on the subway, there are also somewhat more civilized alternatives, albeit at 3 or 4 times the price. If you really want to ride the Harlem line so bad, go ahead and do it – it does stop at various places in the city, including Fordham, so go buy a ticket and get on. Why is it necessary to diminish the experience of the longer distance riders by turning the inner portions of the commuter rails into more crowding and congestion. The notion that one can pack in so many more people into the commuter lines really begs the question Why – sounds like just another number crunching mind-f__ to me. Why mess up the fairly decent to just create a little more crap?

            The long distance commuters are otherwise going to be single passenger autos clogging up the roads and further fouling the air – or else they will just move somewhere else. If you alienate the outer suburbanites, then the trains will be even less profitable and will soon be subway quality. If you want more capacity in the former territory of the 3rd Ave El, just build it out again, as was promised when it was torn down.

            Some of the Bronx lines could be built out further into the burbs, say to Yonkers or Mt. Vernon and the suburbanites who want to ride the subway could get the real thing.

            There is nothing wrong with having a higher class of service, especially if it is successfully attracting people who would otherwise drive into the city. Maybe we should be making the bad better rather than the good worse.

          • Alon Levy

            Those civilized alternatives don’t serve the city; ridership at the city stations is minimal. In the suburbs the mode share is weak – Westchester is 23%, Nassau is 18%, Suffolk is 6%, Rockland is 8%, Dutchess is 6%, Fairfield is 10%. Compare this with the Grande Couronne here: Yvelines is 31%, Seine-et-Marne is 27%, Essonne is 28%, Val-d’Oise is 35%. These are all pretty wealthy departments – Yvelines is in the top 3 nationwide (the other two are Paris and Hauts-de-Seine), Seine-et-Marne and Essonne are top 10, Val-d’Oise is about 15th. Somehow they manage with trains that are not designed around 100% seating.

            As for making the bad better: what do you think high off-peak frequency is? What do you think free transfers with buses and the subway are?

          • adirondacker12800

            They don’t serve the city, except that they keep the suburbanites from clogging things in the outer boroughs, an excellent goal. Gridlock is a pain. If there are whole train loads of people in Stamford who want to get to Manhattan the train doesn’t have to stop every ten blocks in the Bronx. The people in the Bronx can have their own trains that stop every ten blocks. It ain’t Peoria. There’s enough demand to have two different trains.

          • adirondacker12800

            …and make up your mind, either there is never going to be much more demand than there is now because the population is growing so slowly or there will be enough demand for every ten minutes from Poughkeepsie.
            It’s unclear, to me anyway. whether or not the tunnel under the West Side Yards is one track wide or it’s wider and only one track is installed. 12 Metro North trains and three or four long distance trains an hour would be difficult even though it’s a short stretch of single track.

          • johndmuller

            Alon, I suppose that you are talking about two different things, but the words “mode share” seem to be the same – in your post of the 10th above you say, “mode share is weak – Westchester is 23% … Dutchess is 6%, Fairfield is 10%” whereas not very far above that, on a post on the 9th, it says, “Metro-North claims 80% mode share on peak-hour Manhattan-bound commutes”.

            I’m all for running close-in locals to serve city stations, and you can charge less if you want for those trips, providing you don’t (a) steal trains from the existing commuter services [i.e. get some cheaper equipment to run the rush hour economy class trains]; (b) frak up the throughput on the main lines by stopping to many trains in the way; (c) figure out what to do with all this rolling stock in the terminal stations and approach tracks during rush hour and where the new yards to park them all will be. Naturally, no such down sides during off-peak, but also less need/de$ire to do it either.

            I think the empire connection tunnel is only one track wide, at least in part, if not in full, which it quite well could be. Of course, the rest of the ROW is one track, probably expandable to 2, but would also need serious bridge work, probably flyover tracks at SD, in-city station construction (with an extra station track) and likely some kind of electrification.

            A lot of these considerations apply to the Hell Gate branch as well, like extra turnout tracks for (at least some) intermediate stations, additional line tracks, electrification and rolling stock, possible choke-points (the East River tunnels and perhaps the eponymous bridge). While there is room along this ROW (which is not necessarily true of the Harlem River segment of MN or the Empire connection) for this kind of stuff, the room is not necessarily where one might want it (like particularly Astoria).

          • adirondacker12800

            Steam railroads tended to over build things. The Hell Gate Bridge may have some obscure future proofing in it like being able to hang outriggers off it. The viaduct through Queens too. If it’s four tracks there aren’t enough of them to handle lots more freight, intercity, commuter and subway.
            The Hell Gate Line in the Bronx is really really wide. I spend an hour one afternoon when I was very very bored looking at it on tax maps … plenty of space for all sorts of fun. Separated from one another during regular service
            The Empire Connection on the West Side is moderately wide. At this moment Google Satellite view is showing the open cut just west of Tenth Avenue between 43rd Street and 44th. There are two tracks with extra space. Whether or it it’s enough for four is a good question but two would probably be enough until a tunnel, bypassing it, for the high speed intercity trains, gets built.
            The bridge over the Sputyen Duyvil needs to be replaced. Replacing it with a fixed bridge would probably cause all sorts of problems with disrupting the park etc. .. build a short tunnel. It can then be “enlarging the park and restoring the waterway”

          • Alon Levy

            The Empire Connection is double-track, with a single-track pinch point over the bridge. There are perennial plans to double-track it; they should be part of any Empire Connection plan. Hell Gate has four tracks, of which three are in use – two Amtrak, 1 CSX.

            Current inbound peak Metro-North frequency: 15 Hudson, 16 Harlem, 20 New Haven. They run 3-and-1 on Park Avenue because what’s reverse-peak frequency. There’s 5 tph from Poughkeepsie *today*.

            What I’m proposing is to use Penn Station Access (inc. Empire Connection) diversions to make it feasible to run 4 tracks normally, with some frequency boosts on lines for ridership from the Bronx and Yonkers (which takes buses to the subway more than commuter rail). It works out to about the same peak suburban capacity as today or a bit more, which is fine – trip times are unlikely to degrade much, because more regular schedules allow trains to run with less padding, and suburbanites may need to stand for 15-20 minutes in the afternoon but then they’ll get a place to sit. They’ll complain, but they’ll still ride the trains, just as people in Riverdale ride the 1.

          • adirondacker12800

            They take the bus to the subway because if you work at Columbia-Presbyterian going to Grand Central isn’t particularly useful? Or lots of other places on the Upper West Side? The take the NICE bus to the subway because going to Penn Station isn’t particularly useful if you work one of the hospitals along Queens Blvd. Or Boro Hall?
            The track maps that evaporated from the ‘net showed one track under the West Side Yards. I’ve never found anything documenting how wide the tunnel it’s in, is. The bridge is two tracks wide. Since there’s only a train an hour in each direction it would kinda silly to maintain two. If it’s going to be replaced, two tracks wide would make sense. Might not have rails immediately but two tracks wide, whatever replaces it. Tunnel means it can avoid crossing tracks or flyovers/duckunders etc. and the whining and lawsuits about how it going to ruin the viewshed to the river.

          • johndmuller

            Seems like the part under Penn and the nearby section (under/around the convention center ?) are likely single track in a single track wide enclosure. This video is a (unfortunately from the back window) of a train from Penn to the junction with MN. At the beginning, it looks like just one track, but it could be that there is more room than we can see. When it leaves that tunnel, there is more room on one or both sides, but that may not be available beyond what can be seen there. Somewhere else, (RR.net?) I saw something similar, but with better lighting; seemed the same, but hard to tell if there is anything stopping one from making it bigger.

          • johndmuller

            Sorry, the url in that link starts off the video in the middle (my bad); one needs to drag the red bar at the bottom back to the beginning to see the Penn Station part (unless Alon wants to fix the url?).

          • newtonmarunner

            John, there are tons of service quality improvements under Alon’s urban regional rail plan for MNR.

            New Haven Line is still express routed in the Bronx, has a 1-seat ride to Penn NY and Penn NJ, and a cross-platform transfer to Union Sq. and Fulton St., and places New Rochelle get 12 tph [and places like Darien get 9 tph peak service (triple the 3 tph they are currently getting)] and half that off-peak (waaay more than they are currently getting). And free transfers to the subways and buses.

            Harlem also gets waaaay more service on and off peak. Mt. Vernon, Bronxville, Scarsdale, White Plains, etc. get 24 tph (8x the service they currently get), a cross-platform transfer to Penn NY and Penn NJ and a 1-seat ride to Union Sq. and Fulton St., and a 2-seat commuter rail ride to Borough Hall and Barclays. Places like Chappaqua get 12 tph — or 4x the number of tph they currently get. And all get free transfers to the subways and buses, major increase in off-peak frequency and all the things Bronxville, Scarsdale, Mt. Vernon get.

            Tunneling under 3rd Ave. to Yonkers and Mt. Vernon doesn’t solve anywhere near the number of problems that turning commuter rail into an express subway/regional rail hybrid does.

          • adirondacker12800

            If the southbound train is full when it leaves Mount Vernon it doesn’t do people in the Bronx much good. Or vice versa. There’s enough demand to run two different trains

          • johndmuller

            There’s a tendency for all those tph numbers to make one’s head spin sometimes, so I’m gonna paraphrase and talk lines, because we have a notion of how they work, at least in the subway. So you take a couple of branch lines and max them out and combine them on a two track RR tph reckoning would have that at about 15 tph / branch or 30 tph total, call that the nominal capacity – plus or minus depending on how good or how reckless you are operationally. The following is written with MN & Amtrak in mind, although it might work for other combinations as well.

            The system as a whole has 5 streams of traffic, the 3 Metro North lines, Hudson, Harlem & New Haven, Amtrak on the NEC and Amtrak/Empire on the Hudson line. Initially, the Amtrak streams go to Penn Station either via the Hell Gate or Empire connection routes and the three MN streams go to GCT via the Park Ave viaduct/tunnel. If we imagine that each of the MN streams is a pair of lines, which is sort of how they operate, we have the necessary trackage inbound until Mott Haven, where all three combine into only 4 tracks. At this point, the MN trick of running 3 against 1 sort of works – increasing the throughput somewhat, but probably not enough to handle the unfettered capacity of all three MN lines, especially considering that they each are drawing from 3 or 4 tracks, instead of just the 2 in the basic model in the 1st paragraph. So I think that the plan here is to split off some of the Hudson line’s traffic onto the Empire connection and some of the New Haven line’s traffic onto the Hell Gate branch, soaking up some of Amtrak’s anemic usage on both of its streams and allowing MN to carry greater numbers than they would otherwise be able to. Counting all lines, there should be nominal capacity of 60 tph each to GCT and Penn, plus whatever extra can be squeezed out of the 3 versus 1 pattern on Park Ave.

            Given that ESA is in effect, freeing up slots in NYP and in the east side tunnels, these MN streams could be implemented as run-thrus, at least during peak times. Dual mode locos with LIRR shoes could do this today, although additional electrification and/or rolling stock modification could make for more flexible or efficient choices of power.

            There is the implicit assumption that Amtrak is willing to cooperate with Metro North, but since Amtrak is sort of dependent upon MN’s tracks for large parts of both the Albany line and New Haven line stretches, it is reasonable to assume that there would be at least some cooperation. Given that they execute the plan reasonably well, this concept appears to be a very fine, sensible and workable program, with or without further mainline expansion in Manhattan.

          • adirondacker12800

            Metro North wants to run trains to Penn Station, Amtrak owns Penn Station and it’s approaches. The foamers love to see struggles worthy of Dagny Taggart. They play nice with each other most of the time. Just like Amtrak has to pay Metro North to use their tracks Metro North is going to pay Amtrak to use their tracks. They will come to an agreement.

          • newtonmarunner

            John, the 3-to-1 doesn’t work. It doesn’t allow worker flexibility due to lack of frequency — particularly off-peak frequency — and lack of connections (no free transfers and no connections to other job clusters). Parents can’t take their kids to daycare, then go to work on current commuter rail service scheduling, or pick up their sick kid midday. Nor can a janitor who cleans your cozy Midtown office or nurse go in for the night shift under current commuter rail service.

            Further, the 3-to-1 wastes valuable space and capacity. Trains have to be stored somewhere midday; the way not to have to store them is to run them all day. As a result, much valuable Manhattan space is wasted. With 4 tracks from 125th St. to GCT, there should be at least 96 tph running during rush hour; anything less is wasting capacity. These are major reasons why through running with frequent all-day headways are necessary to have a more efficient and useful transit system.

          • adirondacker12800

            Trains have to be stored at night. Sundays. Quite a few of them all day Saturday.

        • johndmuller

          newtonmarunner, do the effen math.

          Three tracks in and one track out obviously can get more trains into GCT than two in and two out; likewise three out and one in can get more trains out of GCT than two out and two in. That much ought to be 100% obvious, no matter what numbers you want to use for tph. Of course, if you want to reduce maximum service, then go ahead and use 2 and 2 all the time, the 3 and 1 is about optimizing the peak.

          Whether or not one can process all of these trains in GCT in the morning and get them out of the way – either into daytime storage or back out the tunnel/viaduct – in time to keep receiving more trains, that is the interesting part. [One thinks, in the real world, that MN keeps a lot of the diesel sets in the terminal during the day and attempts to rotate the electric ones out again as much as possible. That would be because the diesel sets serve the outermost precincts and by the time the later portion of them could be run back out to start another run it would be too late for the rush hour already.]

          Since the morning outbound flow does not have to run so rapidly through the tunnel/viaduct, they can be run closer together (but slower). The theory is that one can get more trains out through the tunnel/viaduct running slower than you can running faster. Thus you get speed in the peak direction and salvage some of the lost capacity in the off peak direction by going slower; after reaching Mott Haven and later Harlem/NH split in the MN system, one can reclaim the full use of the line speed in both directions. [This theory depends on signalling systems and starting / stopping profiles , so it could benefit from more quality analysis than just this back of the envelope stuff, but I believe it to be substantively true nonetheless.]

          This is merely about optimizing the Park Ave viaduct/tunnel; it has little to do with reverse commuting, which is more than amply served by a fraction of the peak direction flow anyway. Whether or not one can keep up with the inflow of cars from the 3 lines using this system, the throughput is still better than it would have been otherwise and one hopes that the extra platforms and storage tracks in GCT can absorb the excess long enough for the rush hour tide to slow and to then send out more trains than are coming in. Obviously the evening rush just does all this in reverse.

          • adirondacker12800

            Seems that, in the evening rush, they run, going east to west, northbound, northbound, southbound, northbound.

            If it’s mostly Hudson line trains on the westernmost track, there’s less crossing over, in the busy part in Mott Haven. Wily railroaders. If Commodore Vanderbilt hadn’t bought the land 150-ish years ago it might not make sense to store trains in Midtown. He did. They leverage that.

      • Eric

        “There is so much unused tracks on the Harlem Line that I’d rather start with regional rail”

        Me too – yet I think there should be demand for an express SAS in the more distant future.

    • newtonmarunner

      Also, light bulb went off, again. Maybe instead do Alon’s idea of a Utica to NJ Subway Line vía Bed-Stuy, Williamsburg (relieving L and providing A with a branch free 2-seat ride to DT Williamsburg assuming the G gets sent to Atlantic), LES, 3rd or 5th local to Midtown (hitting 42nd, 50th, 59th) Super-Express on UES, then NW eliminating the need for the 3 train stops on 145th/148th Sts. (so untangling the IRT Bronx Lines is easier, Lex Express and 7th Express can get 30+ tph each, and so University Ave. could eventually get a branch from Yankee Stadium) while connecting to 2/3, CPW Local, and 1, and eventually taking over a Washington Hts. branch to NJ.

      Just don’t ask me where we get the $$$$.

  10. Jeff

    Let’s be honest, the current mta is pretty bad at new construction. Every project is way over budget and way late. A crosstown line under 125th St sounds great, but does anyone actually think that this MTA can finish it in our lifetimes? Why not make it easier for them?
    Bore new metro-north tunnels from botanical gardens to the existing tunnel at Park/96th, bypassing the Bronx and Upper Manhattan. Extend SAS via cut and cover to riverfront, use extended Harlem greenway to elevate train to use vacated metro-north bridge, continue to botanical gardens and add some infill stops. If you also tunnel from Yankee Stadium Station you can vacate the Park Ave elevated and create a new Park Avenue Highline from 97th to 144th in the Bronx.
    Faster commuter rail, more local service, a tourist trap for the upper east side and all work that the MTA is probably capable of.

  11. kingofcapital

    I don’t think the reason for the deep tunneling in Phase 1 was to avoid street disruption. In part, it was to avoid undermining building foundations along 2nd Avenue. Also, the 63rd St. tunnel had to be quite deep because it was headed under the East River in one direction and under the Lex line and Park Ave. tunnel on the other side. So the SAS branch off 63rd began low.
    As for Phase 2, based on the maps in the MTA 2nd Ave community office on 125th, even further construction along 2nd Ave (leaving aside the turn and segment on 125th) will entail some hard rock tunneling because the bedrock is very close to the surface at points — in particular, between the two tunnel segments built in the 70s. (I’d always wondered why they built two disconnected sections. We’ll leave aside why they built those two segments 35 blocks north of the closest SAS segment at the time.)
    The NYT story in December laid out the appalling featherbedding, the lack of any incentives for politicians or contractors to rein in costs, and the MTA’s general ineptness in constructrion. But the NYT’s oft-repeated claim that the MTA’s costs per mile are six times other cities’ seems like apples to oranges, since most other cities don’t have to contend with schist. (Are the comparative extensions even underground? Through densely built-up areas?)
    I looked up the costs of Crosslink in London — comparable in depth and in the complex weaving under and through other existing tunnels — and the cost there per mile was only about double the cost for SAS, the Hudson Yards or the East Side Access. That makes the NY costs look not so insane when you consider that the north side of the Thames is clay, not schist.

    • Alon Levy

      Crossrail is not comparable in weaving to SAS. It had to weave between many older Underground tunnels. Look up “eye of the needle.” Nor could it build stations cut-and-cover, since they were under older stations. SAS instead passes under nothing (it hooks to 63rd Street) and has a wide street to go under.

      • kingofcapital

        Sorry, I was addressing two related things — cost and depth — and probably wasn’t clear.
        The cost/mile figures the Times cites are for all three NYC projects: SAS, Hudson Yards extension and East Side Access. The other two involve a lot of weaving/dodging (ESA under Park Ave tunnels and under buildings along west side of Park, I believe; the 7 extension cuts through the unused lower platform at 8th Ave/41st, then under Lincoln Tunnel mouth).
        You’re right that there was less threading entailed in building the 63rd-96th stretch. But it was still very deep boring through bedrock. The SAS starts out very deep at 63rd for the reasons I stated. I believe the tunnel was not brought closer to the surface for fear of undermining adjacent buildings.
        So the 6x cost comparison seems bogus to me. The better comparison when you look at the cost per mile for the three NY projects is Crosslink. And all three tunnels in NY had to be quite deep and through schist.

        • Alon Levy

          SAS phase 2 isn’t through schist and has even higher projected cost per km than SAS phase 1.

          The 7 extension tunnel weaves, but the only station doesn’t. Crossrail has difficult station locations, right above or below older stations, or in one case underwater. The amount of material removed for some Crossrail stations, like Canary Wharf, is more than what was removed for SAS or for some $250 million/km Parisian extensions.

          And the undermining argument seems weak, since everything except the turn to 63rd Street is under an avenue wide enough for four tracks, let alone two.

  12. kingofcapital

    You’re right about no schist on 2nd Ave — I misread the map. The TBM is being used for the turn and the 125th St. portion.
    I was baffled by the depth of the line and the stations. Then I read that the deep path was chosen because of fears of undermining foundations of large buildings if they used cut and cover. I’ve searched but can’t now find that cite. I would guess that cut and cover would have been much more disruptive to street traffic than the deep boring.

  13. Michael Biggar

    This guy has no clue about mining.
    Are you an Engineer?
    I was there, you weren’t.
    Small digs? Okay buddy.
    TUNNEL BORING MACHINE is the only option
    Good luck with cut and cover

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