Category: Good Transit

Commuter Rail Stop Distribution

One of the features of American commuter rail is that it’s intended to be used by suburbanites. The propensity for making nearly every station a park-and-ride, with poor pedestrian access, is one effect of this. Another effect is stop distribution. It’s not just stop spacing – many commuter lines have tighter stop spacing than some European and Japanese lines – but rather where the stops are dense and where they aren’t. Normally, a commuter line will have densely spaced stops in the city, where the population is denser and there are more connection points and important destination, and thin out in the suburbs, where speed is more important. American commuter lines are different – in the city they make very few stops, since they don’t connect well to local transit and are treated as too special, but in the suburbs, at least the inner suburbs, they have very frequent stops.

For examples, let us compare Metra and the Paris RER. I’m choosing the RER because it’s an express system, meant to provide fast service within the city rather than comparable stop distance to the subway. Some RER lines even have a slightly American-style station distribution, if they don’t go deep into suburbia, making them more like express subway lines in New York, though even then the difference is much smaller than in the US, without even such long nonstop segments as 59th-125th Streets on the A/B/C/D. Metra is where the American stop distribution tendency is the most extreme, though the lines I picked are those for which Wikipedia lists mileage for stations. All distances in the following table are in kilometers and start from the Chicago terminus or from Châtelet-Les Halles.

UP North BNSF Line Milwaukee North RER A to Marne-la-Vallée RER A to Cergy
4.5 2.9 4.7 2.8 1.8
10.5 6 10.3 4.8 4.5
15.1 11.3 13.2 7.8 9.1
17.7 14.5 14.5 12.3 10.5
19.3 15.5 16.4 14.5 14.8
21.4 16.1 18.7 ~15.5 17.5
23.2 17.7 23 17.6 18.8
24.5 18.8 26.1 20 25.6
25.4 19.8 28 22.7 29.7
26.7 21 30.3 24 ~32.5
28.5 22.1 34 30 34.8
30.9 22.7 36.9 35 38.6

Observe that the stop spacing for the first 3-5 stops is very express, but drops to that of an average subway for the Metra line beyond that. The UP-North line is especially egregious – despite serving the densely populated North Side, it barely stops there, letting the Red Line do all the work. Meanwhile, on the RER A, this is not the case – although stop spacing tightens slightly beyond the first few stops, the effect is small. Even the long nonstop segment between Etoile and La Défense (the second and third stop on the RER A to Cergy) is not enough to create the same effect seen in Chicago, and to some extent other American cities.

Bear in mind, the RER is explicitly an express railroad, though it is fare-integrated with local transit within Paris proper. Systems called S-Bahn, as well as commuter rail in Japan, range from operationally indistinguishable to operationally barely distinguishable from wholly-urban rapid transit. Thus their stop spacing is much smaller, especially in the urban core.

Part of the issue is that there’s not much development around railroads in American cities, since development follows arterial roads and urban transit instead. This is related in both directions to the failure of commuter rail to provide good urban service: there’s upzoning around subway and light rail stations, but not around commuter rail stations. But even when there is development near commuter rail stations, such as around Forest Hills in New York, service is suburban-focused (midday LIRR frequency to Forest Hills is hourly).

Whatever the ultimate cause of this, the result is that commuter rail is not usable where people are most likely to ride transit. Thus it is not too useful for a transit revival. The present revivals proceed from the inside out, starting from the urban core and expanding to outer-urban neighborhoods and then inner suburbs. At each stage, it’s useful to expand transit a little bit beyond the reach of the revival to capture additional ridership, and perhaps hit an anchor, and so there’s room for additional transit use from farther out. This is short-circuited when urban and suburban transit are kept segregated. So far it’s not been enough to prevent some transit revival in some American cities, such as New York and Washington, but it’s a problem in such cities as Boston and Chicago and may prove a problem everywhere once cities run out of subway-accessible areas.

Park and Rides, and Good Planning

Some people with experience in American bus planning have come strongly for park-and-rides, as a convenient means of concentrating all people boarding buses at one spot in order to improve frequency. The charge is led by Joel Azumah of Transport Azumah, who, responding to my question of whether it’s worth it to have strongly peaked buses, says,

Instead of running a separate park & ride and regional service, you can broaden the span of park & ride service. That would allow you to use some buses more than once or to add the early & late buses for flexibility. Park & riders that use services with a narrow span will drive in if they think their schedule is going to change. The extra buses will reduce that tendency.

In this view, the primary purpose of off-peak service is to provide peak riders with extra flexibility, making it a loss leader. This is indeed one of the main purposes of an all-day clockface schedule, as opposed to the essentially peak-only service provided by nearly all North American commuter lines. And yet, one part of Joel’s response bothered me. Observe that he contrasts his view with “running a separate park-and-ride and regional service.” In other words, a bus that serves a park-and-ride can’t serve walkable residential and commercial suburban strips. While this is a plausible constraint for an express bus, it is not a real issue for commuter rail, as long as the commuter rail is done right: trains make multiple stops, and those can include both walkable towns and some regional park-and-rides.

Of course, American commuter rail is without exception done wrong. This manifests itself in three different problems, all of which make park-and-rides look much more important than they actually are.

First, the rolling stock used, except on the LIRR, SEPTA, and Metro-North, is substandard. In particular, trains hauled by adapted freight locomotives take a long time to accelerate to even medium speed: the MBTA’s current trains lose 70 seconds just accelerating from 0 to 60 mph, and the FRA-compliant improvement, using Colorado Railcar DMUs, only cuts this to 42, as established in Table 3.1 of the Fairmount Line study. For comparison, modern EMUs, even of the FRA-compliant variety, lose about 13 seconds. The result is that trains can’t make frequent stops while maintaining acceptable average speed. Thus the service pattern already includes widely separated stops, forcing people to drive to stations, and moreover involves complex patterns with express trains.

Second, nearly all agencies, assume because of tradition that they can only serve peak riders to the CBD. Occasionally there’s some reverse-peak service, but its usage as a percentage of employment in the suburbs served is trivial. Even Metro-North, perhaps the most forward-thinking agency for reverse commuting, is uncompetitive for suburban employment. Stamford has a ridership of about 4,000 employees, in addition to about 3,000 residents working in New York; the total number of transit users working in Stamford is 8,600, itself only 11% of the city’s employment. This pattern in which nearly all ridership is inbound peak reinforces itself, and agencies do not usually try to provide adequate off-peak and reverse-peak service. The MBTA provides two-hour service off-peak on most lines. The LIRR runs trains one-way on the Main Line during peak hour, to allow the peak frequency of 20 trains per hour to run express trains rather than just locals.

And third, invariably, the suburban stations are all park-and-rides themselves. Some are explicitly configured as such, such as Metropark and Route 128. Those are good and need to be there. The problem is that pretty much all stations are friendlier to cars than to pedestrians. Sometimes they’re located outside the towns they purport to serve – for particularly bad examples, look at satellite photos of Plymouth and Westborough. Plymouth’s station is to the north of the old train station and town center, robbing the station of pedestrian traffic, and because Plymouth’s ridership has to come from drivers, the MBTA prefers to have most trains skip Plymouth entirely and just serve Kingston-Route 3, a standard park-and-ride. In a similar manner, Hicksville has a fair amount of development near the station, but so much parking that it’s poorly connected to the station for the pedestrian. Even Providence, Worcester, and New Haven get stations without much pedestrian-oriented development nearby; Providence, the best of the bunch, has development, but it’s sterile residential plus a mall flanked by pedestrian-hostile arterials.

The result of all this is that there isn’t a single example in the US of a commuter line, rail or bus, where most people walk to the station. Thus, issues including off-peak ridership and development near the stations look unsolvable. Those park-and-ride users grumble about difficult parking and do not take trains except to the city during rush hour. Who will drive to take a train that comes every two hours when it’s possible to just drive to the city?

Commuter rail done right does not have this problem, because it runs good (high-performance, low-energy consumption) trains with only one or two staff on board, and so it can run with long span and high frequency while serving many stations. This is roughly how many modern light rail lines in North America operate: there are a few park-and-rides, and a lot of stations located in between that are accessible to pedestrians and interface with feeder buses.

But for mainline rail, one has to look for examples outside the US. In Japan, new transit construction outside the dense city cores is accompanied by intense development near stations: see, for a recent example, the Tsukuba Express. Shopping centers and dense residential areas will generate ridership all day and in both directions; park-and-rides exist, but do not occupy center stage as they do in the US. Likewise, in Germany, one of the practices that evolved in the recent transit revival is closely spaced stations, located everywhere a railroad intersects a walkable place; speed is maintained via trains with good acceleration and level boarding, resulting in average speeds that match those of American commuter lines despite the shorter interstations.

The political infrastructure that exists in Germany and Japan and allows this and is absent in the US is coordinated planning. There is no way a single entrepreneur can create all the required development and local transit coordination. Transportation isn’t web entrepreneurship; it has no Mark Zuckerbergs or Larry Pages, who can almost singlehandedly create all the agglomeration required to support the new technology. Most of the time, this is done by cooperative government planning. The rest of the time it’s done by established conglomerates, usually combining real estate and transportation, including the Hong Kong MTR and the private railroads in Japan.

There is also some component of technology there. Small-scale entrepreneurs can run express buses, which can’t adequately serve many stations while maintaining competitive speed, much more easily than they can run trains, which can. They cannot run trains at all in the closed-access paradigm that rules American (and Japanese) railroading; they have an easier time in open-access Europe, and yet even then most private players are again big conglomerates, such as Veolia and Virgin.

Although transit must make room for the private sector, a transit revival that relies on uncoordinated private players will necessarily fail. Britain, the most privatized of the countries with a revival (high-income East Asia has no revival, as in the big metro areas transit never declined in the first place), needed to revert to public infrastructure planning with Network Rail, and maintains some of the key features of cooperative planning, including integrated tickets and fares. The rest of Europe contracts out services, but still strives to improve intermodal and interagency transfers; in Switzerland, transfers are timed even when multiple operators are involved. The role of people like Joel and the other private-sector players is to bid for operating routes that fit into a combined system, and add service (still within a fare union!) on thick routes where timetable coordination is less important.

What this means is that a transit revival must include more competent government planning. If there had been no Interstates, and certainly if there had been no expressways built by the states from the 1930s on, some of the railroads would’ve survived to do planning entirely in the private sector, as is the case in Japan. But given that there’s nothing like Japan’s private railroads in the US to plan integrated transportation using market principles, the government needs to do it, and it needs to do it well. It can’t privatize everything; the operators will just loot it for subsidies and neglect any components of development that don’t lead to immediate profit. And it needs to learn from some of the practices of express bus operators, but recognize when it can do better than just copy them.

Trip Chaining

Gendered Innovations’ charts of trip chaining and gender breakdown of public transit riders got me thinking about how different systems of transportation handle a mixture of short and long trips. Eric Jaffe at The Atlantic Cities reports this and suggests that transit agencies orient physical features such as accessibility to the needs of women who trip-chain care and work trips.

But to me, the first observation is that although women trip-chain more, it doesn’t seem to be true that women are more likely to ride transit in the US than men just because of trip-chaining features. Instead, women traditionally have been less likely to have jobs requiring commuting, and the commute gap has been shrinking more slowly than the gap in employment.

This comes from the fact that trip chaining on transit is cumbersome in most cases. Both cars and transit have to deal with the time it takes to stop for an errand, but transit tends to handle this worse, unless it’s very frequent and has practically zero access and egress times. Transit cities instead get people to take their short errand trips on foot – since their neighborhoods are denser and have more mixtures of uses, they make retail and care trips attractive on foot. In light of the fact that walking is not useful for long commute trips and transit is not useful for short errands, we can construct the following typology of cities:

Long \ Short mode Foot, bicycle Car
Transit Transit-oriented Traditional suburban
Car New urbanist, small-town, auto-oriented dense Auto-oriented

Auto-oriented cities are the easiest: in those places, people drive for all purposes. Trip chaining can be done on a commercial arterial road, dropping off laundry or kids or buying something on the way to work, and because of ample parking availability, the time each additional link in the chain consumes is very small, since the longest access and egress time comes from navigating from the residential cul-de-sac to the arterial and from the arterial to the office park.

Traditional suburbs, common around New York and Chicago and sometimes in other old North American cities, are similar for trip-chaining purposes. In those areas, the urban form is suburban and auto-oriented, but work trips to the city are done by commuter rail or occasionally commuter bus, since the city is not as auto-friendly as the suburbs.

Transit cities too have their long-range commuter rail, but it is built as an extension of walking rather than of driving. Neighborhoods tend to have mixed uses, and there’s a concentration of retail development near the outlying stations, sometimes forming large secondary clusters but sometimes just acting as neighborhood centers. It could take considerable time to add more trips to one chain, especially if not everything is located at the train station. But conversely, the amount of time a single short trip takes is small, unlike the case for auto-oriented cities – the supermarket is right around the corner, and within five minutes’ walk are plenty of stores. When people walk, the concept of a single trip begins to lose meaning then. Potentially, every single purchase can be considered a separate trip, in which case the chaining becomes quite long.

In many places the transit is absent and people drive outside the neighborhood, while still doing errand trips on foot. This is the typology that characterizes different environments including new urbanism, traditional cities like Providence and Tel Aviv that have been made car-oriented, and auto-oriented modernist projects such as Co-op City. Those environments all differ in how trip chaining is done. In principle, it can be done on foot, but usually people who can drive do.

If my own experience is any indication, one feature of cities in this typology is that children and teenagers walk more. In Tel Aviv, my father drove me to elementary school on the way to work while (in later grades) I walked back, and I took the bus to and from middle school. Most trips my parents did in a car, but there was a reasonable number that were short enough to walk. I’d walk to farther destinations such as the cinema and the urban mall. The view of the North Tel Aviv middle and upper-middle class of the 1990s as I remember it is that the bus is fine for trips to school, but adults drive. I doubt I’d have had the same view if I’d grown up in New York, or for that matter in the Houston suburbs, where everyone drives or is driven.

Although most of the discussion about transit cities contrasts them with car-oriented cities, the other two typologies need to be examined, too. When adults and children trip-chain differently, children can get a distorted view of who transit is for (poor people, people who can’t drive yet), and the next generation will make the city auto-oriented; this is indeed what is happening in Tel Aviv, which despite population growth in the core is adding cars and spawning low-density suburbanization well outside the built-up urban areas.

Likewise, Cap’n Transit’s attacks on park-and-rides don’t quite capture what is wrong with the car/transit typology. A transit agency that wants to make it easier to trip-chain will want to concentrate development near the train stations, because that’s where it’s easiest to add minor trips without having to walk ten minutes out of one’s way. Of course in the middle of the dense city there’s development everywhere, which may well be orthogonal to where the subway is, but then trip-chaining becomes easier because each foot trip is so short.

The principle is that cars are a big one-time purchase but have a much lower marginal cost of usage. If one major class of trips can’t be done on transit – and chained trips generally can’t when they require the rider to wait for the next bus and the next bus will come in 15 minutes – then people will buy a car and then drive it even for trips they’d happily take transit to if they didn’t already own a car. The class of trips that can only be done conveniently by car needs to be kept small enough that people will use car share, take a taxi, or beg a friend who does own a car.

Thus what transit agencies and pro-transit politicians should devote more time to is appropriate development more than physical features of the transit system. Accessibility is important for so many reasons other than strollers. In contrast, the primary importance of using transit to extend the range of the pedestrian rather than provide a capacity boost for the car is precisely that transit needs minor trips to be doable on foot. A transit system that one needs to take to the supermarket may be technically successful, but it’s in a failed urban area.

The Limits of Clockface Scheduling

This is morally the last post in my series on improving the MBTA: see here, here, and here for the three previous posts. However, it’s a more general principle concerning interlined regional rail services.

Good practice for running transit service that isn’t at show-up-and-go frequency – say, anything that comes every 10 minutes or more, certainly anything that comes every 15 minutes or more – is to have regular clockface intervals. This is memorable for passengers, and works as a baseline with which to work on providing extra connections. In addition, if there is interlining, then it makes it easy to schedule trains to come at a uniform frequency on the share segment. If service is uniform throughout the day, then this is very easy. The problems start when it is not.

Normally, if extra peak service is required, then rigid clockface systems, such as those found in the German-speaking world, will usually interpolate in the middle of the period. In other words, if a station gets inbound trains at :00 and :30 every hour, then in the peak it will also get them at :15 and :45. This is what’s done in Stuttgart on two of the S-Bahn lines, interpreting peak very liberally, and less rigidly on the TER in Nice. Many systems instead use similar peak and midday service, dropping service only in the evening, such as the Berlin S-Bahn, and BART.

To see where problems could occur, let us look at Berlin again. There are three services on the Stadtbahn: the S5, the S7, and the S75. At the peak, all three run every ten minutes, with westbound trains departing Ostkreuz at :02, :00, and :05 respectively. Off-peak, the S75 drops to 20-minute frequencies, introducing 8-minute gaps into a schedule whose average headway is 4 minutes.

For a cleaner, contrived example, let’s say we interline two services, each with a 15/30 frequency; a factor-of-2 difference in frequency is more or less the norm on commuter lines in Tokyo and Paris, which do not have rigid clockface schedules – more local lines have a slightly smaller gradient than more long-distance lines. There is an inherent tradeoff between uniform frequency at the peak and uniform frequency off-peak. It’d be much easier to do if both services were bound to have the same frequency but the frequency varied continuously, as it does on most subways; however, what works on a dedicated line when passengers show up and go fails when passengers consult schedules and when timed connections or overtakes are involved.

More concretely, if Line 1 leaves a station at :00 and Line 2 leaves at :08, providing uniform peak frequency of 7-8 minutes, then off-peak we will have a 22-minute gap when we reduce to half-hourly frequency on each line; and if Line 2 instead leaves nearly at :15 to provide uniform off-peak frequency, then there will be a gap of nearly 15 minutes at the peak. The sum of the largest peak and off-peak gaps is necessarily 30 minutes, whereas the ideal would be for the sum to be 22.5 minutes.

Extra constraints can force one choice of gaps. For example, the Providence and Stoughton Lines are (or should be) constrained by the need to fit faster intercity trains on the line, at least in the future; for details of those constraints, see my posts on MBTA-HSR compatibility. In short, if we choose the symmetry axis to be :00, then Providence Line trains are compelled to leave South Station at :02 to meet up with trains to Woonsocket, and high-speed trains leave South Station at :10-11 and begin to overtake Providence trains at Readville at :15. Stoughton trains should then leave immediately after the high-speed trains so that they can leave the line toward Stoughton just before they’d get overtaken (at Sharon, if they continued), which means at :12-13. Thus we obtain about a 10-minute gap at the peak and a 20-minute gap off-peak, which is an acceptable compromise.

In contrast, one thing that clockface scheduling does not limit is short-turns. Indeed the Berlin S-Bahn often short-turns every other train, without trouble. Moreover, it is not difficult to drop to half the peak frequency with short-turns. If a train that leaves at :00 runs all the way to the end and a train that leaves at :08 short-turns (both repeating every 15 minutes), then it is not difficult to change things so that in the off-peak, a train that leaves at :00 or :30 runs to the end and a train that leaves at :15 and :45 short-turns. People beyond the short-turn point would still only need to memorize at what minute between :00 and :29 the trains serve their stations, and it would be regular all day; people before the short-turn point would again only need to memorize one number, from :00 to :14. In the case of the MBTA, this means that the Fairmount Line (which should get a train that turns at Readville for every train that continues toward the Franklin Line) can get a perfectly regular timetable.

Improving the MBTA: Regional vs. Intercity Service

The MBTA commuter rail lines are laid in such a way that there’s an inherent tension between providing local service and providing longer-distance intercity service. It’s less apparent on the Providence Line because the intercity component, i.e. Boston-Providence, follows immediately just from serving the suburbs between Boston and Providence, but elsewhere there are greater problems. Good local service would have intense frequency in the inner portions of commuter lines; unfortunately, most lines only meet right next to the termini, reducing the opportunities to use interlining to create high-frequency inner segments.

Good local service also needs many infill stops, while good intercity service needs higher speeds. My proposals for the Providence Line essentially go with intercity service needs, justified by the facts that Providence is a major anchor, that high top speeds are possible on the line, and that the line should also host high-speed trains. Fortunately, the Providence Line has an opportunity for more intense local service using the Stoughton Line to add frequency; while this would end up overserving Canton Junction and Route 128, Readville and points north would get adequate peak service, and acceptable off-peak service. This is not as true on other lines, especially on the North Side, in which there’s a tradeoff between fast service to outlying cities and good service within Cambridge and Somerville.

Of course, the issues I’ve focused on in my previous post on the subject – electrification, high platforms, modern rolling stock – are useful for both. A fast-accelerating EMU could connect Boston with the various terminals at the same time as today’s express trains while making all stops as well as some extra infill stops. The problem comes from trying to fit trains into a clockface schedule. On a few lines, for example the Lowell Line, it’s actually easier to close very lightly used stations (Mishawum) or stations that are very close to other stations (Wedgemere).

Another issue is outbound extensions. With some, there’s so little traffic beyond the current terminus, or sometimes even beyond a point slightly closer than the current terminus, that the decision should be easy. This contrasts with the MBTA’s approach of proposing more and more outer extensions. With others, the intercity functions make extensions more reasonable, within certain bounds. I believe the following list of judgment calls would be reasonable:

1. Providence Line: no extension required – the line’s natural end is Providence. If Rhode Island wants to provide a low-frequency glorified parking shuttle from Wickford Junction and the airport to Providence, it’s its business, as long as it doesn’t muck up timetabling that’s based on Providence-Boston service.

2. Stoughton Line: an extension to Taunton would work, and possibly even to New Bedford. I’m iffier on Fall River, which has stronger commute ties to Providence; however, Providence-Fall River requires too much new infrastructure to be easy.

3. Franklin Line: either extend it to Milford (which may be easier to serve from the Worcester Line), or cut it back to Franklin. The Forge Park terminus is close to a lot of office park jobs, but the local road network is so sprawled out that it’s not worth the extra few minutes of travel time.

4. Fairmount Line: building infill stations is an excellent idea, though it should be coupled with increase in frequency and service level to make them more useful. One way to improve off-peak frequency is to route all Franklin Line trains along this line, and perhaps add supplementary trains that turn at Readville. The advantage of this is that the Fraknlin and Fairmount Lines used to be one railroad, with a grade-separated crossing over the Providence Line; in contrast, the junction at Readville is flat, making it more operationally cumbersome to have trains cross from one line to the other.

5. Needham Line: no extension necessary – the only possibilities would dismember the line in favor of much lower-density suburbs than Needham. Better would be to eliminate the line entirely and put Needham on a branch of the Green Line, and restore past plans to extend the Orange Line to West Roxbury. This would dismember the line too, but in favor of more service to dense areas rather than less. I don’t know what’s Needham’s commute tie to West Roxbury, but its commute tie to Newton and Brookline is fairly strong, 1,300 vs. 3,400 to Boston and another 3,400 in-town.

6. Worcester Line: Worcester is the natural terminus, so no extension should be entertained.

7. Greenbush Line: Greenbush is the natural terminus. The greatest urbanization is on the coast rather than along the railroad, and this limits the line’s usefulness.

8. Kingston/Plymouth Line: the natural terminus is downtown Plymouth, slightly farther out from the current Plymouth station, which should be renamed North Plymouth or just closed for lack of utility. In addition, Plymouth sends Boston 2,565 commuters, and Kingston only 797. Either the roles of Kingston and Plymouth should be switched – Plymouth would get served all day and Kingston would get only supplemental rush hour trains – or the Kingston branch should be closed, and replaced with a station on the main line.

9. Middleborough Line: for ordinary regional traffic, the line should be marginally cut back, to place the Middleborough station at the center of the town. In fact, there’s a dropoff in commute volume south of Brockton, and yet another south of Bridgewater; Middleborough is a fine terminus, but is not a proper anchor like Providence, Worcester, or especially Plymouth. On the other hand, there’s some potential for intercity traffic to Cape Cod, capturing some commuters as well as vacationers heading the other way.

10. Fitchburg Line: the MBTA’s proposed extension to Gardner looks weak to me, though not completely daft. That entire region of northern Worcester County has much stronger commute tie to Worcester than to Boston, in similar vein to the issue of Fall River’s connection to Providence. The commute tie to Framingham, as in the MBTA plan to have a branch leaving Framingham toward Leominster, is even weaker than that to Boston. It would be better to have a regional line connecting Gardner to Worcester, which would also have the advantage of taking a much more direct route than the freeway network; connecting Fitchburg and Leominster would require more work and compete with I-190 directly.

11. Lowell Line: here an outbound extension is natural and desirable, since Nashua and Manchester have a nontrivial commute tie to Boston and are significant cities in themselves, though as with Cape Cod this would be more of an intercity line. New Hampshire had a plan for such an extension, but it was killed by state Republicans early last year. This is unfortunate, since Nashua in particular has a less than great freeway connection to Boston, which a fast electric train could consistently beat.

12. Haverhill Line: Haverhill is a natural terminus. Although Rockingham County has a strong commute tie to Boston, the greatest part of it comes from very sprawled out towns near I-93, far from the line.

13. Newburyport/Rockport Line: the split at Salem allows natural interlining to give the towns with the strongest commute ties the most frequency. An additional branch to Marblehead would be prudent, providing even more frequency to Lynn, Chelsea, and additional infill stops in Revere. At the north end, Portsmouth looks like a fine intercity terminus, but in fact that part of Rockingham County is a marginal commute market to Boston, better than that feeding into Haverhill but much worse than the I-93 sprawl.

Not discussed above are station placement and infill stations. Station placement is relatively easy, since bad cases like Westborough and the aforementioned Middleborough and Kingston look obvious on a map. In addition, such office park stations with terrible ridership as Mishawum and River Works are already treated as such, so almost all trains skip them and their ridership is very low, making them clear candidates for closure.

Infill stations are harder. The problem is that on the North Side, the four lines split too early. This means that, while infill stations are possible, it’s hard to give them adequate frequency. Short-turning local trains could help somewhat, but is the most difficult on the two lines that serve Cambridge and Somerville, the Lowell and Fitchburg Lines. It’d be much easier to do this with Lynn (which already benefits from interlining and would benefit even more from a Marblehead branch) or Malden (which has the Orange Line).

That said, the Lowell Line might be able to support a local train to Winchester and an intercity train that makes zero or one intermediate stop between North Station and Winchester. The commute market is not great at this distance, though; Belmont has 3,100 Boston-bound commuters, and 290 inbound riders at its two commuter rail stations. A reroute of the Fitchburg Line along the Charles River Branch through Watertown might get more ridership; it would be slower, but it has zero intercity function, compared with strong potential at and east of Brandeis. To succeed, high frequency and short station spacing are required. For an example using the Charles River Branch, see here.

On the South Side, the Worcester Line begs for infill between Yawkey and Newtonville, but some of the people it would serve may already be riding the Green Line. The Green Line doesn’t perfectly parallel the line the way the Red Line parallels the Old Colony Line or the Orange Line parallels the Providence Line and the Haverhill Line, though, and there’s room for two or three stations serving Allston, Brighton, and Nonantum. On the other hand, some of these stations would compete with Watertown somewhat, and are less ideally placed in that the Worcester Line has an intercity function whereas the Fitchburg Line doesn’t.

Finally, another unmentioned issue is the effect of rapid transit extensions, especially of the Green Line. The extension plan to Somerville, which the state is obliged to build as one of many mitigations for the traffic induced by the Big Dig, is effectively a replacement for Lowell Line infill in Cambridge and Somerville; the line would only really need one infill stop to connect to the Green Line, and perhaps the Green Line would need to be extended to West Medford, if not to Winchester. That said, the interaction with rapid transit is more complex than this, and I will discuss it more in a future post.

Improving the MBTA

The MBTA has a problem. And I say this coming from New York, whose standards for good regional transit aren’t all that high, but now Metro-North looks like something to look up to from the MBTA. Ridership on the system is rising, but not very quickly; the MBTA moreover has no plans to modernize. Most of what I’m going to suggest will involve commuter rail, not because it’s the most important portion of Boston’s public transportation but because it’s the part I’m most familiar with and also the part that seems most direly in need of improvements. Put another way, I’m necessarily going to talk about the MBTA as perceived from Providence, rather than from within Boston.

The main difference with New York and past proposals for improvements, both subway extensions and regional rail, is size, and scope. In New York, practically everyone who works in Manhattan takes public transportation or walks. The transit mode share to Boston is lower and the car mode share is much higher. This seems especially true for people commuting from north of Boston.

The main prescriptions will not surprise people who have read my posts on best industry practices. In short, the MBTA commuter rail needs to do the following:

– Full electrification, starting from running EMUs rather than diesels under the catenary on the Providence Line, but also extending to all other lines.

– Level boarding along the entirety of all platforms, rather than just one car length, in order to shorten dwell times to no more than 30 seconds at outlying stations.

– Higher-quality rolling stock, with better-configured doors than the present cars as discussed in a DMU conversion study; all new EMUs available, both FRA-compliant and noncompliant, would be fine, though noncompliant trains with a waiver would have somewhat better performance and lower operating costs.

– Reasonable frequency all-day on a simple clockface schedule: ideally, all branches should have 4 trains per hour at the peak and 2 off-peak – the lowest-ridership lines tend to be the shortest-distance, for which frequency matters the most, whereas the highest-ridership lines (Providence, Worcester) are practically intercity, the higher demand balancing out a lesser need for frequency.

– A fare union with local buses and the subway, so that commuter train tickets are automatically valid without extra pay.

– Relocation of stations to walkable urban areas, away from park-and-rides that only serve to extend the suburbs into Boston rather than extending Boston into the suburbs.

– An end to outbound extensions, such as the ongoing project to extend the Providence Line to Wickford Junction, and instead a shift toward infill stations, especially in underserved Cambridge and Somerville.

In the longer term, a North-South Rail Link is unavoidable – North Station is too far from the CBD, some through-service from south of Boston toward Cambridge is advisable, and the rail link as proposed would give a direct connection to the Blue Line and thus to East Boston and the airport. Although the official cost estimate is $9 billion, for barely 2 kilometers of tunnel and associated connections, such an estimate would make the project more expensive km-per-km than any other I know of except perhaps East Side Access, and a more honest attempt at cost estimation yielded $3-4 billion, on a par with outsized American subway construction costs; at European costs, it would be less than a billion. Observe that electrification could reduce the cost by allowing steeper grades; the official proposal still uses heavy diesel locomotives. In either case, this is far more expensive than the points above; concrete costs much more than organization and electronics.

Let me now explain in more detail what’s happening in and around Boston – more precisely, what is wrong, and potentially what ridership level should be expected of good regional rail.

The main datasets I’ll be working with are the American Community Survey as of 2009, the town-to-town commuter flows as of the 2000 census, and the MBTA Blue Book, offering ridership numbers as of 2009 and going back to 1989. Bear in mind that most data from the 2009 ACS will be scrubbed from the net on January 20th, giving us only 2010 census-based numbers, which undercount immigrants and the poor and thus undercount cities; however, while the 2010 census gets magnitudes of change wrong, it’s very close in terms of absolute populations, absolute mode shares, etc. All numbers I cite here are from the 2009 ACS; you can verify that a source exists now, but not beginning a week from now.

The current background trends to observe are:

– Boston’s population is increasing, quickly. The 2000 estimate base, using a 2010 backdate that also depresses intercensal estimates to fit the 2010 undercount, was 692,745 for Suffolk County, which contains Boston and three small inner suburbs. By 2009, the county’s population was 753,580, a growth of 8.8%. Boston itself had 9.5% growth from the 2000 census, which is not directly comparable to the ACS and the estimate base but is extremely close in numbers. The metro area grew only about 4.5% over 2000 – a little less if one takes the full Combined Statistical Area, which includes slow-growing satellite metros like Providence.

– Transit ridership has grown in the last 10 and 20 years, but by much less than in New York. The Red Line’s grown 50% in the last 20 years, but the other T lines barely grew. The commuter rail grew quickly as lines were put into service in the 1990s, but had little growth in the 2000s, despite high gas prices.

– The Silver Line BRT is very underused, despite the promise and branding as rapid transit on tires. Even for airport service, where the Silver Line gets to the terminals, it gets less than half the ridership of the Blue Line (2,600 vs. 6,900), which only serves a station connected to the terminals by free shuttle buses. The Washington Street branches (SL4, SL5) are more frequented, but their combined ridership is only about the same as that of a single subway station, and are just bus-plus.

– Boston is the opposite of a bedroom community – it has 520,000 jobs vs. 278,000 employed residents, all as of 2000. This 1.87 ratio is much higher than that of New York (1.18), which contains most of its bedroom communities, and is more comparable to that of Manhattan (2.75). The same is true of Cambridge, with 114,000 jobs and 55,000 employed residents, for a ratio of 2.08.

– Unlike New York, both Boston and Cambridge draw substantial numbers of commuters from suburbs outside urban transit range – Boston draws about 200,000, and Cambridge draws about 55,000. Inbound commuter rail ridership on the MBTA is 70,000. Cambridge is a lost cause under current operating paradigms – it has no stations, and if it did they’d be too poorly integrated with the top two employers.

– Total transit vs. car mode share is 26-52 for people working in Cambridge and 37-50 for people working in Boston; the corresponding numbers are 56-29 in New York (including bedroom communities like Queens) and 73-14 in Manhattan (which is more comparable to Boston in terms of workplace geography).

– There are about equally many suburban commuters into Boston from the north as from the south. People driving to the edges of the Orange and Red Lines cannot make too big a difference (Alewife has 2,700 parking spots, and Malden and Oak Grove have just under 1,000 between them), so the difference seems to be that more people are commuting into South Station than into North Station. Observe that South Station is right next to the Boston CBD, whereas North Station is a little farther out.

– Boston has built too much highway infrastructure for a kernel of a transit-oriented edge city to exist along Route 128 as it does in Stamford. 10% of people who work in Stamford take transit to work. There aren’t numbers for all edge cities near Boston, but where they exist, they’re much lower, e.g. 2% in Burlington. Furthermore, since Route 128 exists and is continually upgraded, there’s not much hope of serving these centers by commuter rail from suburbs on the opposite side of Boston.

The upshot of all this is that there’s room to more than triple MBTA commuter rail ridership, while also maintaining healthy urban rail ridership coming from population growth in Boston itself. However, this requires very good service from the suburbs to the city, and the MBTA isn’t providing it. The problem is that the MBTA relies too much on cars: Middleborough and SouthWestborough are particularly egregious for their poorly located stations, chosen for drivers’ convenience rather than for that of transit users. Even worse, Plymouth, a city that’s older than Boston, gets few trains, while most trains serving the Plymouth Line instead stop at a park-and-ride nearby, at Route 3.

Although the focus of all suburban rail is service to the urban core, this can only be done by treating it as longer-range, lower-frequency rapid transit, rather than by treating it as shuttles from parking lots to the CBD (or almost the CBD, in North Station’s case). People won’t use the trains if they’re too infrequent past rush hour; it’s not 1960 anymore, and people do not always work 9-to-5.

For an example of what the MBTA is doing wrong, let’s look at commuter flows in Rhode Island. There are 4,700 people living in Rhode Island working in Boston. The biggest single source of Boston-bound commuters is Providence, with 1,100; Providence Station has 2,000 inbound weekday riders, so it also draws people from some nearby suburbs – but not too many people. Cranston and Warwick have 700 between them – and they’re getting an airport stop with a very small number of trains. Even Washington County, with 170 commuters, is getting a station. Those two stations cost $336 million between them. Meanwhile, Pawtucket, with 600 commuters plus another 800 in suburbs to its northwest and in Woonsocket, is not getting an infill station.

I hope to discuss concrete schedules, possible changes to station placement, and ways to keep operating costs under control in a future post. For now all I’ll note is that the MBTA needs to stop pushing for extensions far out into suburbia. It’s not going to get ridership out of 9 roundtrips per weekday with a 5-hour service gap, which is what the T. F. Green Airport station gets. It’s going to get it out of reliable, frequent all-day service.

Little Things That Matter: Railroad Junctions

One underrated difference between countries is how multi-tracked railroad junctions look. In France, double-tracked regional lines have grade-separated junctions that ensure no crossing oncoming traffic. For a plethora of examples, consult the RER track map and look at any bifurcation. Looking at Google Earth, the same is true near Tokyo. This is standard rapid transit practice anywhere I know of, and Paris and Tokyo both treat their regional rail systems like urban rapid transit.

In the US, this is not true. Even important, high-traffic mainline junctions are often flat – see for examples the Main Line-Hempstead Line junction on the LIRR (Queens Interlocking), and the Hudson-Harlem junction on Metro-North (Mo Interlocking). The major junctions involving the Northeast Corridor tend to be better, fortunately. Harold, the LIRR/NEC junction, is already grade-separated from oncoming traffic, and the current grade-separation project is only for same-direction traffic; and the junctions in New Jersey are grade-separated. The Kearny Connection splits the problem in half – it is grade-separated for NEC trains but requires Morris and Essex trains in opposite directions to cross each other at grade. However, even for NEC trains a few major problems remain, most notably Shell Interlocking between the Northeast Corridor and Metro-North in New Rochelle.

I suspect the problem is that double-tracked lines in the US are not consistently thought of as having one line in each direction. The arrival of centralized traffic control (CTC) has made wrong-direction running easy; some railroads ripped their second tracks, and the commuter lines that remained double-tracked freely run trains wrong-way during weekends or (as is the case on the Worcester Line) when there are freight trains on the line. At a few places, four-tracked segments on running track connect to two tracks in nonstandard ways: for example, at Providence Station, three of the four platform tracks merge into the southbound running track. The concept of having one track per direction and no crossing oncoming traffic, which is standard on the subway, doesn’t really apply to commuter rail, leading to scheduling problems.

In New York, there’s no alternative to grade-separating the worst junctions, including Mo, Queens, the Kearny Connection, and the unnamed Far Rockaway/Long Beach and Ronkonkoma/Port Jefferson junctions. Although frequent train service exists with flat junctions, the schedule is irregular and unreliable, and has few reverse-peak trains. Fortunately, this is a problem for commuter trains more than for intercity trains, for which schedule adherence is more important.

In Boston, the NEC itself has flat junctions at all of its branches. Fortunately, there are alternatives to concrete. The Franklin/Providence junction requires Franklin Line trains merging onto the NEC to cross oncoming Providence Line trains at grade, but lets them continue onto the Fairmount Line without conflict. Since the Fairmount Line is getting some investment and more frequency is under discussion, having additional trains serve the line is a net benefit, and all Franklin Line trains should go through Fairmount. The Needham Line branches at-grade, at a more constrained location, but there are plans to connect it to the Orange Line anyway, and much of its geography is suitable for subway service more than for a regional rail branch. This leaves the Stoughton Line, for which there’s no alternative, but fortunately Canton Junction is not a very constrained location and the junction is simple.

When Should HSR Serve New Urban Stations?

Greenfield high-speed rail lines frequently serve new stations rather than legacy stations; the TGV network is famous for this, and the discussion of whether to place intermediate stations in the city or on the outskirts has arisen in many reports and studies on the subject. What is less commonly discussed is what to do at the main urban stations. More often than not these are the legacy stations, but there are several exceptions.

Those are not the infamous beet-field stations in France, but something quite different – they’re in different neighborhoods from the older stations, but are still in dense urban landscape, often (but not always) as close to downtown as the older stations. Trains do not pass them at very high speed, so they’re chosen primarily to make through-service easier, in cities whose legacy stations are terminals or otherwise difficult to connect through. Indeed, I do not know of a single case in which such new stations are intended to serve as terminals – they are either through-stations from the start, or terminals intended to be used as through-stations with a later extension.

Example 1. Shin-Osaka is located just outside central Osaka, about 4 kilometers from Osaka Station. Osaka Station is a through-station, but there are sharp curves from it to the legacy Tokaido Main Line at both ends, and also there was not enough room to build additional tracks for dedicated Shinkansen use. Since the goal was subsequent through-service west of Osaka, it was easier to build a new station just outside the CBD, at the intersection of the Tokaido Shinkansen with the Tokaido Main Line (now Kyoto Line). The station is also connected to one subway line, which goes to Osaka Station and beyond. Although there has been development near the station, it is a secondary station, with far more traffic at Osaka; a transit-oriented CBD is too compact and dependent on a huge subway network to move so easily.

Example 2. Lyon Part-Dieu was built specifically for the TGV, since the old station, Perrache, was at a poor location for connection to the high-speed line. Part-Dieu is located in a busy neighborhood area of Lyon and has seen ample development, and the Lyon Metro, which is not much older than the LGV Sud-Est, serves it from multiple directions. In addition, commuter trains have been diverted to Part-Dieu from Perrache, so that now the station is France’s busiest mainline station outside Paris. Despite its use as a through-station, the construction of further LGV segments south of Lyon in the 1990s made it somewhat of a terminus for TGVs, while through-trains skip the city at full speed on a greenfield alignment to the east of the urban area or stop along the way, near the airport.

Example 3. Lille’s legacy train station, Lille-Flandres, is a terminus. This was unacceptable for TGV service, not least because the main draw of building a line to Lille was the onward connection to the Channel Tunnel, which was constructed at the same time. Thus, a new station was built a few hundred meters from Lille-Flandres, on the land of a former helicopter base; because of the city’s new position at the junction of high-speed lines to Paris, London, and Brussels, the station was named Lille-Europe. Like Shin-Osaka and unlike Part-Dieu, Lille-Europe is primarily a high-speed train station; Lille-Flandres is much busier (it is the second busiest provincial French station, after Part-Dieu). This is despite the fact that Lille has extensively redeveloped, using the TGV as a catalyst.

Example 4. Because of difficulty reaching Barcelona’s main station, Sagrera, the AVE is initially serving a terminal station a few kilometers to the west, Sants. A new track connection to Sagrera was built, in order to allow full through-service to points north and east of Barcelona. In this case, the choice of a new station was a temporary measure allowing the line to open earlier, rather than a change in alignment.

What all of these examples have in common is different from the usual conception of building new HSR stations, both in an outskirt setting and in a CBD setting. None of these stations has been about digging greenfield tunnels under city center – indeed Shin-Osaka was explicitly about avoiding such tunnels, and Sants was built as a way to allow service to open before such a tunnel were finished. None involves a station cavern; Lille-Europe is above ground, despite its CBD location. None is an urban prestige project.

Indeed, the decision to build a new underground station complex under Marseille’s terminal station, Saint-Charles, is one of many contributing to the very high projected cost of the LGV PACA project linking Marseille (and Paris) with Nice. A though-station very close to downtown exists, and an underground option there was judged slightly cheaper in an alternatives analysis, but all currently considered scenarios involve an underground station at Saint-Charles.

Another thing to observe is that neither Japan nor France compromised on station location in the capital, but at the same time neither built extensive infrastructure for it. None of the Paris RER lines or of the TGV projects has included any provision for building a single central Paris station for trains in all direction; such a station would require a large cavern with multiple tunnels, and the space and money for such tunnels is far more valuable for local transit use. Likewise, Japan has had no trouble cutting back legacy intercity and long-range commuter trains to bring the Shinkansen to Tokyo Station, but stops short of building a new cavern for it. The most it has done is reserve space at Shinjuku for a future tunnel for use by the Joetsu Shinkansen, requiring new subway lines that go nearby to be built deeper.

The upshot in the US is that the emphasis should be on functional train station locations, rather than on the most central locations. In particular, the Amtrak Vision‘s plan to bring intercity trains to Market East and Charles Center through new tunnels should be shelved in favor of the existing 30th Street and Baltimore Penn Station. In addition, a new track connection between Grand Central and Penn Station should be used only by commuter trains, which need it far more than intercity ones (it would also allow tighter curves, saving on expensive Midtown land acquisition), mirroring the fact that no TGVs serve Chatelet-Les Halles. If the example stations in this post are any guide, any Manhattan location south of 60th Street would work for New York’s primary train station, and Penn Station’s location is as good as any.

In California, what this means is not surprising: converting Los Angeles’s Union Station configuration from terminal to through-station is paramount. In addition, at the Bay Area end, it’s fine to end high-speed trains at the existing 4th and King terminal rather than Transbay, until future money for the final tunnel is committed. In the longer run, in San Diego, although the existing Santa Fe depot should be used if possible, another urban location would not be hurtful as long as it had some transit accessibility and was in a walkable location.

Commuter Rail Speed (Hoisted from Comments)

For commuter rail, even more so than urban transit, there is a tradeoff involving speed, cost, and coverage. Higher speed is useful all else being equal, but all else is frequently not equal. American commuter rail is on average faster than European and East Asian commuter rail, but fails because relative to the distances people travel and the amount of sprawl it must compete with it is quite slow. Because of the need for higher speed, my previous commuter rail modernization proposals have featured average speeds higher than those that are normally found elsewhere.

That said, speed should be increased by means of better rolling stock, adequate maintenance, and better timetable adherence leading to less schedule padding. The American practice of running low-frequency trains from each suburban station expressing to the main city station makes service worse rather than better. Consider the following practices:

In Paris, RER trains are more or less local. There are some trains skipping stops, but in RATP territory (see schedules here), trains will just skip a few stops, rather than running truly limited-stop. In SNCF territory there are some express trains. In addition, the Transilien trains run on legacy routes even in the city, and run express outside it; often they’ll run nonstop between Paris and the terminus of the parallel RER line.

In Berlin, the S-Bahn lines run local. As in Paris, there are regional lines that are separate from the metro-like S-Bahn, and those make fewer stops in the urban core.

In Tokyo, there are local trains and rapid trains. Local trains make all stops. Rapid trains come in several flavors – they only stop at select stations, but sometimes there are several levels of rapid trains (all on the same tracks). The busiest lines have a track pair dedicated to local trains, and a track pair dedicated to express trains, and then there are usually two consistent express patterns, one more express than the other. The local trains (Yamanote, Keihin-Tohoku, Chuo-Sobu) run on dedicated tracks and are very metro-y in their lack of branching, and the rapid trains run on separate lines and look more legacy, just without the brand separation of France and Germany. In addition, there’s less separation of infrastructure.

For example, the Chuo-Sobu Line has local trains running to Mitaka, and the Chuo Rapid Line has trains making limited stops to Mitaka and local stops farther west as well as trains making limited stops all the way, with timed overtakes at the express stations; the express trains’ stopping pattern is consistent. Consult this schedule for details (click on “interval timetable”).

The speed of all of those lines is quite low – for example, the RER A averages 47 km/h between Boissy-Saint-Léger and Saint-Germain-en-Laye. However, this comes from short station spacing, coming from the fact that they serve dense urban areas, with reasonably dense suburbs. The need for speed in Paris is much less than in Boston or even New York. In Paris, 20-30 kilometers out of the city one already leaves the built-up area. Even in Tokyo, a much larger city, Takao, 53 kilometers from Tokyo Station, is near the end of the urban area. In contrast, Providence is 70 kilometers from Boston, and Ronkonkoma is 80 kilometers from Penn Station.

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.