New York-New Rochelle Metro-North-HSR Compatibility

Let me preface this post by saying that there should not be any high-speed trains between New York and New Rochelle, except perhaps right at the northern end of the segment. However, to provide reasonable speeds from New York to Boston, it’s desirable to upgrade the maximum speed between New York and New Rochelle to 200 km/h or not much less. The subject of this post is how this can be accommodated while also permitting some regional rail service, as proposed by the MTA. There are two reasons to bundle the two. First, some of the work required could be shared: for example, new stations could be done at the same time as rail and tie replacement. And second, the presence of both upgraded intercity rail and regional rail on the line requires some four-tracking and schedule optimization.

The physical infrastructure required for boosting speeds within New York City is fairly minimal by itself. The right-of-way in the Bronx has some curves but they are not very sharp and can be somewhat straightened without knocking down buildings, and even the curves in Queens and on the Hell Gate Bridge, while unfixable without major viaduct modification, are not terrible if superelevation is high and tilting is enabled.

A big question mark is what the maximum speed permitted by the physical layout of the East River Tunnels is. Current speed is 97 km/h (60 mph), but top speed today in other sections of the network are below those achieved decades ago (for example on Portal Bridge), and trains with specially designed noses, as the Shinkansen rolling stock is, could potentially go even faster. Regardless, it is not important for HSR-regional rail integration, since the East River Tunnels have no stops and will be running far under capacity once East Side Access opens. Thus, all travel times in this post are between New Rochelle and Sunnyside Junction, which is notionally considered to be located at 39th Street. This is a 25-kilometer segment.

Another question mark is what the speed limit on the S-curve south of New Rochelle is. Currently the limit is 48 km/h (30 mph). Raising it requires grade-separating the junction between the NEC and the current New Haven Line. It can be raised further via curve straightening, but the question is how much eminent domain can be done. The maximum radius that can be achieved with minimal or no eminent domain is 700-800 meters. Some further eminent domain may be required to have this curve start far enough from the southbound platform that full 200 mm superelevation is achievable without subjecting local train riders to too much cant excess. For comparison, slicing through New Rochelle and the Pelham Country Club allows essentially eliminating the curve and allowing maximum speed through the area, which taking surrounding curves into consideration is about 240 km/h.

Assuming 150 km/h (about 700 meters radius, 200 mm cant, and 175 mm cant deficiency), the technical travel time for a nonstop intercity train between when it passes New Rochelle and when it passes Sunnyside is about 9 minutes; this includes slowdowns in Queens and the Bronx and on Hell Gate. A nonstop M8 with a top speed of 145 km/h would do the same trip in about 11:15. (Amtrak’s current travel time from New York to New Rochelle is about 25 minutes, of which by my observation riding Regional trains 6 are south of Sunnyside.)

Even the above travel time figures require some four-tracking, independently of capacity, in order to limit cant excess. Unlike the Providence Line, the Hell Gate line has some curves right at potential station locations – for example, the Hunts Point stop is located very close to the curve around the Bruckner Expressway, and the Morris Park stop is located in the middle of a curve. The Bruckner curve radius is about 500 meters, and 200 mm superelevation would impose 80 mm cant excess on even a fast-accelerating commuter train (1 m/s^2 to 72 km/h), and an uncomfortable 140 mm on a slower-accelerating one (0.5 m/s^2 to 51 km/h). The Morris Park curve is even worse, since it would impose a full 200 mm cant excess on a stopped train. So we should assume four-tracking at least at the Morris Park station, which is located in the middle of a curve, and Hunts Points, and potentially also at Parkchester.

Now, a local train would be stopping at New Rochelle and four stops in the Bronx, and should be stopping at Sunnyside. Although a FLIRT loses only about 75 seconds from a stop in 160 km/h territory, assuming 30-second dwell times, the M8 is a heavier, slower-accelerating train, and for our purposes we should assume a 90-second stop penalty. This means that, counting New Rochelle and Sunnyside together as a single dwell-free stop (they involve one acceleration and one deceleration in the Sunnyside-New Rochelle segment), local technical travel time is 18:15, about the same as what Amtrak achieves today without stops but with less superelevaiton and inferior rolling stock.

Now, 18:15-9 = 9:15, 9:15 times the schedule pad factor is 9:54, and modern signaling allows 2-minute headways up to 200 km/h; thus we can accommodate 4 tph intercity and 4 tph local Metro-North without overtakes except at New Rochelle and Sunnyside.

There is only one problem with the no-overtake scenario: the MTA plans on a peak traffic much higher than 4 tph, in line with the New Haven Line’s high demand. It’s planning on a peak of 6-8 tph according to what I’ve read in comments on Second Avenue Sagas. This naturally breaks into 4 tph that make local stops and 4 that do not (though my suspicion of MTA practice is that it wants fewer than 4 local tph); if there are fewer than 8 trains, one slot could be eliminated.

Let’s look then at a 4/4/4 scenario. Assume that trains depart Sunnyside in order of speed – HSR first (passing rather than stopping at Sunnyside), then express Metro-North, then local Metro-North. A local train will be overtaken first by the following HSR, and then by the following express. If we could move the overtake point to New Rochelle, the local would not need to wait for trains to pass it. In reality, 4/4/4 means the local departs Sunnyside 4-5 minutes after the HSR train passes it, and has 9 minutes of time penalty before being overtaken again. If the stop penalty could be reduced to 75 seconds, then the overtake could be moved to New Rochelle, demonstrating the use of top-quality rolling stock. But the M8s are good enough for many purposes, and therefore we will not assume a noncompliant replacement, unlike in the case of the MBTA, whose rolling stock is slow and very heavy.

With 9 minutes of time to make up, it’s tempting to have an overtake at a four-tracked Co-op City station. But then the local would have to be overtaken by two trains in a row, and moreover the two trains would become quite separated by then due to differing top speeds, and this would force a penalty on the order of 6 minutes.

I claim that the best would be to four-track a segment between two or even three stations; the right-of-way is wide enough anyway. In addition, the Morris Park curve could be straightened if the Eastchester Avenue overpass were modified, and doing this in conjunction with four-tracking would be cheaper than doing each alone. Under this option, the local would leave Sunnyside much later than 2 minutes after the express, just enough to be overtaken by HSR at Morris Park. It would then keep going to Co-op City until overtaken by an express. This would essentially save about 2.5 minutes out of the 6 in penalty, since the train would be in motion for that time.

19 comments

  1. Zmapper

    Sorta related question: Alon, do you know if Stadler can even make a FLIRT with a floor height of 48 inches?

    • Alon Levy

      I don’t. My guess is they can; in general, it’s easier to have higher floors. (Besides, some of the S-Bahn equipment used in Munich, which is high-floor has the same initial acceleration as the FLIRT and a higher P/W ratio.) The only equipment that could plausibly not work with higher floors is the medium-floor Talgo, which might have center of gravity problems if the boarding height is increased too much.

      • Zmapper

        In that case, it is likely that Stadler would have to make two variants of the FLIRT for the North American market. One would be FLIRTNA22, with a width of 10′ 6″ or so and a platform height of 22″. The other would be FLIRTNA48″, same width, 48″ platform height.

        Interestingly enough, the width of recent rolling stock for Norway and Finland is 10′ 6″, so the same product could simply be renamed as the FLIRTNA22.

      • dejv

        Talgo has a double decker on its drawing boards (talgo 22 IIRC) so I think they would be capable of building high floor vehicle. The COG should not be an issue anyway because passeneger space has very low specific weight comared to any other devices.

  2. Adirondacker12800

    Another question mark is what the speed limit on the S-curve south of New Rochelle is. Currently the limit is 48 km/h (30 mph).

    Shell interlocking? I don’t know if the track maps you have are up to date. The threads on Railroad.net were all a-twitter because they had been raised to 45 MPH with the rebuild a few years ago. You’d need a current Amtrak employee timetable.

    http://www.railroad.net/forums/viewtopic.php?f=67&t=56146

    Same maps note 45 over the Pelham Bay Bridge at Co-op City. Is that 45 because of the curve or 45 because it’s a 100 year old movable bridge?

    If you are going to be sending 12 trains an hour into the teeth of another railroad running 14, 15, 16 trains an hour at peak you need flyovers. If you want to turn trains around at New Rochelle you need tail tracks and probably a flyover. Over the railroad or just north of the station where things widen out even more. Like Rahway to Avenel but with higher speeds.

    Build the new stations with two tracks. Leave empty space in the middle for two more tracks some time in the future. It’s not going to be that much more expensive. In the future the expense is laying new track, not tearing down stations and rebuilding them.

    • Alon Levy

      Rich E Green’s map from 2009 says 30 mph. He did say on railroad.net that speed limits had been lowered, and that could have been one of the places.

      Yes, flyovers are necessary. The reason I even brought up the possibility of straightening the curve with takings (whereas 700 meters is about the maximum possible within present ROW geometry) is that the dominant expense is building the grade separation, so they might as well take some houses. Either way, it’s not a good practice to have HSR cross oncoming traffic at-grade. The reason I’m so annoyed at Harold while supporting grade-separating Shell is that at Harold there’s no sharing with oncoming traffic, only with same-direction traffic, and even that could be reduced with some reorganization at Penn. For the record, 150 km/h with a radius of 700 meters vs. 48 km/h is a difference of about 90 seconds, whereas 240 vs. 150 is another 25; here 240 is the upper limit of what’s feasible given surrounding curves. Those extra 25 seconds are not very cheap since the takings they require are substantial, but they’ll become even more expensive if the grade separation locks in a lower speed.

      The speed restriction through bridge over the Hutchinson River is geometric, alas – on the track map, the restriction appears next to the curves on both sides of the bridge, rather than through the bridge itself as is the case with Cos Cob. ROW geometry has a much higher limit if the bridge is moved a bit to the southeast or if the approaches are straightened.

      • Adirondacker12800

        You need current employee timetables. The timetable he was looking at may have reflected speeds just after construction, when they had temporary speed restrictions for some other reason… or they found that they weren’t good for 45. Who knows. I vaguely remember the whines when the Record of Decision was announced.. that flyovers would have been much faster. … but flyovers cost a lot of money.

        Looking at the satellite views there’s commercial properties along the railroad at that point. The tax maps should have information about current use. Pity New Rochelle isn’t in the Westchester system yet. Tax maps can be interesting, things like at E. 177th St. the ROW is just under 308 feet wide.

        The NYC tax maps are painful to use but usable. I gave up trying to look at online California tax maps, where they exist. ( San Mateo or maybe Santa Clara has decided digitized tax maps are proprietary and can’t be on the web. ) Looks like the UP ROW through Fresno is 200 feet wide. Difficult to tell because what seems to be the ROW is on the tax rolls as industrial. And while the NYC maps are a pain to use and very slow the ones in California, where they exist, are almost impossible to use. 200 feet wide hard up against a freeway, should be plenty of space for passenger rail and freight rail….

        The Pelham Bay Bridge has been there forever, I think it’s the third iteration. They had good reasons to put it where it is, it was all swamp when they built it, could have put it anywhere. Civil engineering and passenger expectations have advanced… but then they wouldn’t be building something new in a worthless swamp they’d be building in sensitive wetland. Move the ROW southeast much and you are moving away from the customers in Co-Op City.

        • Alon Levy

          I’ll try to see what properties actually are along the tracks in New Rochelle. I try to stare out of the train every time I pass it, and my recollection is that the properties most at risk from straightening the S are storage facilities. A flyover shouldn’t require taking residences, though what should happen and what can realistically happen are sometimes different.

          The Pelham Bay Bridge move is just for the bridge, not the ROW on land. The idea of the move is to convert two short, sharp curves into one long, gentle curve. The same thing should be happening over the Cos Cob Bridge at the same time it’s raised: by taking about one building, they can practically eliminate any geometric speed restriction in that area.

          • Adirondacker12800

            Tax maps or a foamer that knows New Rochelle… Interesting stuff on the street view of Webster Ave and Beechwood Ave, it’s 6 tracks wide if not wider. Birch Street is probably commercial on the west side, it’s not very pleasant to live next to a railroad and an oil company. ( Probably was a coal company back in the day, which is even more unpleasant ) …I’m sure somebody on Railroad.net has the Sanborn map of 1924…

            I think we are defining “bridge” differently. To me the bridge is straight, the curves are on causeway fill on either side of the bridge. Move any of it and you are mitigating changes to a sensitive wetland. Not impossible but not cheap or easy…. Public hearings all across Baychester and the Pelhams about the historic significance of the sunken barges just south of there….

  3. jim

    For what it’s worth, the 2002 document envisaged five Metro-North trains per hour at AM peak in both directions: two express New Haven-Penn, three local Stamford-Penn. It’s likely that that’s changed in the last decade, but the Amtrak Gateway slides only envisaged six tph at peak New Haven and Hudson combined.

  4. anonymouse

    Knowing Metro North’s preferred model of service, there will probably be about two local (all stops) trains per hour, and maybe a couple more making one or two stops along the way, with the remaining trains being non-stop. This should make the capacity on the Hell Gate Line manageable, as will triple or quad tracking a few select sections. As far at the Hutchinson River bridge is concerned, the speed restriction is both due to the curves and the movable bridge. Making it a fixed span would also allow easing the curves north and south of it into one big long curve all the way across the bridge, making for a reasonable transition from the 100 mph running to the north to the 70 mph running to the south without slowing down to 45 (as per the track maps).

    • Alon Levy

      One thing I didn’t bring up in this post is the possibility of having trains stop at Port Morris and Astoria, which cannot possibly be four-tracked at reasonable expense. That is still possible; the absolute upper limit is about 8/8, but then the trains have to enter the two-track section as express-express-local-local on a 15-minute takt as opposed to having even spacing, and even that requires perfect punctuality. The advantage of not trying to do everything without overtakes but instead doing an overtake between Port Morris and Co-op City (or, better yet, between Parkchester and Co-op City) is that it allows adding these infill stops without destroying the schedule too much. With those stops, there would be a total of 8 stops between Penn and New Rochelle, which is reasonable spacing for a regional line.

      Of course, all this assumes it’s even possible to construct stations on the ramps leading to the bridge.

      • jim

        The 2002 document addressed Astoria. it ruled out a station there for three reasons: (1) not enough room for more than four-car platforms, (2) high construction costs, (3) low projected ridership. There was also a worry that it would mar the view of the bridge.

        • Alon Levy

          I’ll believe 1 and 2, but re 3, what assumptions did they make on frequency and fare integration with the subway? I imagine that the ridership at such a station would be far higher if the fares were integrated with the subway and the frequency were at a minimum 4 tph all day.

          • Adirondacker12800

            The Triboro line is going to be taking up two tracks isn’t it? Get on the Triboro if you want to go to the Bronx, Change to Metro North at an interchange station somewhere in the E130s. Want to get to the Island, go to Sunnyside on the N or Woodside on the Triboro and the 7. For trips into Manhattan all it’s going to attract are people who can walk to the station and want to go to Penn Station. Any other origin or destination the BMT can get you there faster.

          • jim

            I’d bet a large sum of money they didn’t assume fare integration🙂.

            The document didn’t say what their service parameters were. A full service plan was promised for the next document, but no next document was produced. But presumably the same service parameters were used for all the potential stations and Astoria came out at or near the bottom (Coop City came out at the top). Also a significant chunk of the ridership would have been diverted from the subway. You and I might say that’s a good thing: we’re offering these people a choice of transit options; but the FTA would see it as cannibalizing a sales channel. It wouldn’t be enticing new transit riders. So it wasn’t just low ridership; it was the wrong sort of riders.

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