The Wrong Kind of Branching

Transit lines branch. Core routes have more demand than outlying ones, so naturally trains and buses run on trunk lines in the core and then branch farther out, to match frequency to demand. I gave an overview of this years ago. This is both normal across nearly all significant transit systems, and good practice. In this post, I’d like to focus on the opposite kind of branching, which I am going to call reverse branching, when one outlying line splits into two core routes. This is much less common, but exists in multiple cities, and leads to problems including restrictions on capacity and disappointing ridership. Cities should avoid building new lines that reverse branch, and in one famous existing case, London’s Northern line, the city is working on changing the situation by building a new outlying branch.

London’s Northern line, as can be seen on the Underground map, has three branches to the north and two in the center, but just one to the south. The highest ridership demand is in the center, but because both branches feed into just one southern branch, there is less than full capacity on the central branches, about 20 trains per hour each, compared with 30 tph on the southern branch and 33 tph on the Victoria and Jubilee lines. As a result, Transport for London has made recurrent plans to split the line for good: one central branch (through the City of London) using the existing southern branch and two of the northern ones, and one (through Charing Cross) using one northern branch and terminating at Kennington, the junction with the southern branch. An under-construction extension of the line from Kennington to Battersea can then be tied to the Charing Cross branch. There is some NIMBY opposition from a member of Parliament representing a constituency on one of the northern branches, who would like her constituents to have one-seat rides to both branches, but most likely, Transport for London’s need for capacity will make the split inevitable once the Battersea extension opens, ending the reverse branching practice.

In New York, routes branch and recombine, and thus it is common to have trains of different colors (which only denote Manhattan trunks) running together on a branch in Brooklyn, Queens, or the Bronx. The single busiest entry point into the Manhattan core is via 53rd Street Tunnel (connecting to Queens Boulevard), technically a branch since it runs trains connecting to both the Eighth and Sixth Avenue Lines. This, again, causes capacity problems. It’s not so bad on the numbered lines, where four trunk tracks (the Manhattan express trunks, carrying the 2/3 and 4/5) recombine in a different way to four tracks in Brooklyn (pairing the 2/5), but the lettered lines’ reverse branching in Uptown Manhattan and Queens initially forced eight trunk tracks (the Sixth and Eighth Avenue services, the B/D/F and A/C/E) to converge to six branch tracks (the two Queens Boulevard express tracks via 53rd, and the four Central Park West tracks). New subway connections have replaced this situation with twelve trunk tracks (including the Broadway Line’s N/Q/R) splitting to ten, spreading the problem around but not dealing with the fundamental restriction on capacity. The under-construction Second Avenue Subway will connect to the Broadway Line and run Q trains, raising the number of lettered tracks Uptown and in Queens to twelve, but this will not be enough to disentangle the tracks and provide full capacity on each core track; see below for proposed examples.

In Delhi, the Green Line splits into short branches, to provide transfers to two different Metro trunk lines. As seen on the system map, the Green Line does not enter central Delhi, and the current setup allows passengers to travel to central Delhi via two different routes. However, the Phase 4 extension plan extends the one branch to go out of the city in a V-shaped direction (the light green Kirti Nagar-Dwarka Section 28 line on this map), and has an extension that may connect to the other branch (Inderlok-Indraprastha, colored ocher on the map) to connect it to central Delhi, which may cause a serious mismatch in demand on the outlying common segment.

Finally, in Tokyo, subway lines reverse branch in two locations. The Namboku and Mita Lines share their southernmost three stations and the tracks in between. Although most Tokyo subway lines, including Namboku and Mita, run through to commuter lines, which provide the normal kind of branching, the Mita and Namboku Lines only do so either to the north or via the shared segment, as seen on this map, constraining capacity. They run only 12 peak tph each, and have low ridership by Tokyo subway standards. The Fukutoshin and Yurakucho Lines are in a similar situation, but the Fukutoshin Line does run through to a commuter line, the Tobu Tojo Line, without going through the shared segment (it is not depicted on the map, which is a few years out of date). The Fukutoshin Line has low ridership (see last page here), but the Yurakucho Line does not.

In all examples I’ve listed so far, the two core branches serve very central areas (as in London, New York, and Tokyo), or neither of them does (as in Delhi). Tokyo is somewhat of an exception, since the Yurakucho and Mita Lines serve Central Tokyo and the Fukutoshin and Namboku Lines serve secondary centers, but those secondary centers are very dense themselves; the Mita and Namboku Lines in particular are quite close in ridership. I am more wary of proposals to split an outlying line in the core that have one branch serving the CBD and one branch avoiding it, as in Delhi, assuming I understand the proposal correctly.

Also of note, all the examples I’ve listed involve subways. This is because conventional branching, with a core trunk splitting into multiple outlying branches, is more limited on urban rail than on both buses and regional rail. Most subway lines do not have more than two branches feeding into a trunk. In New York, not counting the split in the A, which is inherited from the LIRR, there is exactly one place where three subway routes share tracks: the N, Q, and R from Manhattan to Queens. In Stockholm, with its highly branched subway network, only one line, in one direction, splits into three. This is because even a split into three branches requires limiting off-peak frequency on the branches to less than a train every ten minutes, which is undesirable in large subway systems. The result is that reverse branching can easily create a situation in which there are more tracks in the core than in the outlying areas, as it does in all four cities surveyed above, restricting capacity on each core track.

In contrast, regional rail tends to operate at lower frequency on the branches, and this permits conventional branching with more than two branches per trunk. In addition, there are often turnback facilities at through-stations, and substantial four-track segments on otherwise two-track lines. The result is that reverse branching is possible without any constraint on core track capacity. The Berlin S-Bahn is highly branched in both the conventional and reverse senses. The RER E is being extended to the west, including a takeover of an RER A branch. And the Tokyo commuter rail network has extensive reverse branching, coming from through-service between commuter lines and subway lines but also from the Shonan-Shinjuku Line’s split from the Tokaido and Tohoku commuter lines. In none of these cases is there a significant restriction on core capacity, simply because there’s enough slack in the branches that they can’t fill to track capacity unless the core has filled as well.

In the US, I am familiar with three proposals for new subway lines that involve reverse splits, in Boston, Washington, and New York.

In Boston, the proposal actually involves commuter rail rather than the subway: the Worcester Line would use the Grand Junction Railroad to go through Cambridge to reach North Station, bypassing South Station. See map on page 38 of the statewide transportation capital budget proposal. This would not reduce capacity, since the Worcester Line is nowhere near exhausting the capacity of a two-track railroad, and moreover, the Grand Junction line would terminate at West Station within Boston proper, where there’s a railyard. However, this is still bad transit, for other reasons. West Station serves a residential neighborhood, without enough density to justify a fork toward both North Station and South Station. On top of that, since North Station lies outside the Boston CBD, the proposal is essentially a mixture of a radial and a circumferential line, with all the problems that would bring – and despite running as a circumferential line through Cambridge, there is no transfer planned with the Red Line, although the Grand Junction passes close to the Kendall/MIT station.

It would be better to bag all plans to use the Grand Junction until such time that the state builds the North-South Rail Link, connecting North Station with South Station. Then, the Grand Junction would make an almost perfect alignment for a circular line, with its eastern leg connecting North and South Stations and its western end going through Cambridge, making several stops, including a transfer to Kendall/MIT. This would require high investment – besides being a single-track at-grade line, the Grand Junction would require a new junction to connect to the Worcester Line to go east toward South Station, whereas today it only connects to the west, toward Allston and Brighton – but still a fraction of the cost of the North-South Rail Link, which is getting some serious political support, including from former governors Michael Dukakis and William Weld.

In Washington, there already is some reverse branching: the Yellow and Blue Lines share tracks in Virginia, but run on two different trunk lines in Washington proper, each shared with other lines, so four central tracks become four tracks in Virginia. But now with the opening of the Silver Line, raising the number of Virginia tracks to six, WMATA would like to separate the Blue Line from the Orange Line, which it shares tracks with in Washington, in order to provide six tracks across the District as well. This can only lead to awkward service patterns and wasted core capacity, as Matt Johnson demonstrates on Greater Greater Washington: because the Orange and Silver Line will keep interlining under any plan, reckoned from their split east there are only four tracks in Virginia and not six. Moreover, the Yellow Line interlines with the Green Line in the District, which means that even if it’s separated from the Blue Line, it could not run at full capacity.

Washington built itself into a corner with its Metro route decisions. There’s no corridor in the city that really needs a subway line; unlike New York, Los Angeles, and San Francisco, Washington has no corridor with so much bus ridership that it should be a subway line. A fourth subway line would be useful for service to Georgetown, but that’s about it. So decisions about a fourth line in the District should be based on the capacity needs of the branches, not those of the core. On a list of possible changes that WMATA looked at, Greater Greater Washington included a separated Silver Line, including separation up to the junction with the Orange Line so that they share no tracks. I’ll add that if WMATA wants to go down that route, then it should give the Orange Line its own route through the District and keep the Silver and Blue Lines together; this is because the Orange Line is the busiest of the three, so that it should be the least branched, in this case not branched at all whereas the other two do branch.

Finally, New York. Second Avenue Subway is going to change the nature of the reverse branching used by the lettered lines, for the better. Because the plan for Phases 1 and 2 is to run only the Q train, the city will finally have matching numbers of lettered tracks in and north and east of the Manhattan core: twelve tracks in the core, and twelve in Uptown Manhattan and Queens. Unfortunately, it is impossible to match service, because that would sever too many connections. Second Avenue Subway only connects to the Broadway express line, so to match service there couldn’t be any other service using the Broadway express.

Recall the London NIMBYism mentioned at the beginning of this post: that was about a service change that would give commuters a cross-platform (see comment with diagram) transfer between their branch of the Northern Line and the central segment of the other branch. In New York, the transfers in western Queens involve a lot of walking between platforms, if they even exist. Then all the Broadway locals (the N/R) would go to Queens through 60th Street Tunnel, and thence to the Astoria Line, severing the connection to the Queens Boulevard Line. The Queens Boulevard Line has two ways into Manhattan: 53rd Street, which connects to both Eighth and Sixth Avenues, and 63rd Street, which connects only to Sixth Avenue. Moreover, either all F trains (through 63rd) have to run express in Queens and all E trains local, or the reverse; mixing and matching would produce at-grade conflict at the junction, as seen on the Queens 1 track map on nycsubway.org. The transfer between the E and F would be located at 74th Street in Queens, several kilometers east of the split, which is located just to the east of the westernmost express/local station, Queens Plaza. Neither the E nor the F would have a transfer to the N/R near their respective intersection points. The Q would not have a transfer to the E (it would have one to the F, though). This puts many commuters in an impossible situation and the capacity gains from it are frankly not enough to be worth it.

Instead, the capacity gains would be limited to running some more express trains on the Broadway Line. Before the service cuts in 2010, the N ran express on the Broadway Line, the Q terminated at 57th Street at the north end of Midtown, and a fourth Broadway route, the W, ran local and served the Astoria Line. Once the Q is extended up Second Avenue, the restored W could beef up Broadway Line service. Second Avenue would only get a branch despite its high ridership, but it’s still only a segment of a line.

Then there are Phases 3 and 4 of Second Avenue Subway, serving Midtown and the Lower East Side, where the Q runs on Broadway. The official plan introduces another reverse branching: a new route, the T, is planned to run the entire length of Second Avenue: see map here. When both phases are complete, there will be fourteen lettered tracks in Midtown but only twelve Uptown and in Queens.

To resolve this, the MTA should activate a connection that is included in the Second Avenue Subway plan as a non-revenue connection: a connection from Second Avenue south of the Q/T split at 63rd Street to 63rd Street Tunnel; currently, 63rd Street is the least used connection from Manhattan to Queens, since the reverse branching limits capacity and 63rd Street is the least useful connection since it enters Manhattan north of Midtown. This implies there should be a Queens Boulevard-Second Avenue service, which I will call the U, one letter next to the T. The Queens Boulevard express tracks are filled to capacity and the local ones are not, so the T should run local, cutting the frequencies on the existing local R and M trains a bit to make room. It would still leave New York with twelve Uptown and Queens tracks diverging to fourteen Midtown tracks, but it would distribute the load better, in the same way the present system distributes the load better than the 1930s-era reverse branching from six to eight tracks did.

New York is in a somewhat special case, in that its subway system is based on heavy branching and reverse branching, and moreover it’s historically based on three different systems, with poor transfers between them. Fully untangling the lines after Second Avenue Subway’s Phases 1 and 2 are built is not possible because there are no transfers between the lines that would result, and the station placement is such that any new transfers would involve long walks between platforms.

Other cities, especially cities planning new systems from scratch, should not emulate this feature, and should instead design all lines to either not branch at all or only branch conventionally. A system designed from the ground up could have cross-platform transfers between lines, and even make sure they’re timed, reducing the cost to passengers of having to transfer in lieu of using a reverse branch. It could be coherent, in the sense of making it easy for an unfamiliar passenger to understand how to get from each station to each other station. And it could be built for maximum capacity in the most crowded segments, where it matters the most.

North-South Rail Link Diagram

In my post about large-diameter TBMs, I proposed using them to bore Boston’s North-South Rail Link. Like the official plan, this calls for two pairs of tracks, one feeding Back Bay and thence the Providence and Worcester Line and the other feeding the Fairmount and Old Colony Lines. Since there are three sites for stations – South Station, Aquarium (for the Blue Line connection and the north end of the downtown office cluster), and North Station – this calls for a design in which the middle station has right-way cross-platform transfers, and the two end stations have wrong-way cross-platform transfers. Here’s a diagram, consisting of half this arrangement. Top end denotes either North Station or South Station, bottom end denotes Aquarium.

The assumed bore diameter is 12 meters, which corresponds to 1 meter = 16 pixels. The dashed lines are galleries punched at regular intervals into the two bores, connecting the platforms at stations. The assumed operating speed is 90 km/h; this requires a curve radius somewhat higher than 300 meters, about the lowest that can be achieved beneath the Central Artery, assuming no underground surprises.

Moving one track aside, as done between the second and third image and between the fifth and the sixth, requires 3.4 meters of lateral displacement, which at this speed is almost all curve spiral rather than full curve, encouraging using a higher curve radius and shorter spirals. Near the lower limit of the curve radius that permits 90 km/h, the spirals would be longer than the curve itself. With a 1,000-meter curve the track would do the transition in 118 meters. Switching the heights of the tracks, as done between the third and fifth images, requires 5.5 meters of vertical displacement (possibly a bit more, depending on catenary clearances, but certainly not more than 6 meters); I can’t find information about vertical curve radius at low speed, but if the same vertical acceleration as at high speed works, then using Swedish standards, 1,300 meters works, in which case, with EMU-friendly 4% grades, the transition requires 190 meters. 118+190+118 = 426, less than the distance between each pair of stations, if not by the most comfortable of margins.

The advantage of this configuration is that people making diagonal trips, such as between Framingham and Braintree, could transfer cross-platform at South Station. With two stations, as is the case in Singapore for the transfers between the North-South Line and East-West Line, passengers on one of the wrong-way pairs would need to travel one station farther than they have to on each line; with three, passengers between two points on lines north of Boston feeding two different tubes, for example Salem and Waltham, could transfer cross-platform at North Station.

Finally, the reason for two tubes rather than one is that it makes the portals simpler, especially at the southern end. I discussed above the transitions between different configurations of tracks inside the tube, but the transitions from an at-grade two-track line to a two-track tube with one track above the other require more vertical displacement, and this favors two separate portals to the south, one pointing at Back Bay and one pointing due south toward Fairmount and the Old Colony Lines. Merging the two bores underground is possible, but the cost differential with just doing two bores all the way may not be enough to justify the reduction in capacity.

Authoritarian Leaders and Agenda Setting

On Tuesday, Andrew Cuomo proposed a new signature initiative: a $450 million AirTrain to LaGuardia, connecting to the Mets’ stadium on both the 7 train and the LIRR. The proposal has practically no merit even as an airport connector: Ben Kabak and Yonah Freemark both note, with helpful graphics, that the connection is so circuitous it’d be slower than the existing bus-subway options to nearly every destination, including everywhere in Manhattan. Capital New York notes that in general, transit activist reactions to the plan were cold, precisely because it’s such bad transit.

The interesting aspect of this is about the counter-criticism, and the discussion it led to. (In contrast, Cuomo’s general hostility to transit and intercity rail is not news, and it’s unlikely someone with such a history could come up with cost-effective transit plans.) The main reaction to the criticism is not “where would you spend $450 million instead?”. That question has a few answers, all of which are boring: the general MTA capital plan, or, if the money is to go to expansion, Second Avenue Subway Phase 2, the next item on the city’s transit agenda now that Phase 1 is nearing completion.

Instead, the main reaction is “how would you connect to LaGuardia instead?”. That question, too, has a definite answer, which Ben talked about in his post, and which I pointed out in my post about airport connectors last year: an extension of the N to the east, with several stops (for example, at Steinway and Hazen) to serve more of Astoria and not just airport riders. The N takes a direct route to Manhattan, passing through or next to the top areas for LaGuardia passengers, as seen in the second map here. But even that is the wrong question. There are probably more cost-effective subway extensions in New York, having nothing to do with LaGuardia; I have to say probably, since at no point has the MTA proposed large enough a slate of possible extensions that we can compare projected costs per rider and say “this is the best.” There might even be better ways to extend the N eastward than to LaGuardia: an elevated line over Ditmars, a short segment of the Grand Central Parkway, and Astoria Boulevard would serve East Elmhurst, a dense, transit-deprived section of Queens, and would probably produce higher ridership than a swerve from the GCP to the airport.

Such is the power of a governor who’s accountable to nobody: he proposes a scheme, and even the criticism is on the governor’s own terms of providing service to LaGuardia. Yonah compares travel times to various destinations on various alignments for connecting LaGuardia to the subway. Nate Silver’s response has an infographic with travel times from the airport to city hall in various American cities – an infographic that is of little use to New York, where the main destination is far north of city hall, but is well within the general topic of LaGuardia’s airport connections. Even I, cognizant of this agenda-setting power, have to at least mention an alternative LaGuardia connector, knowing readers will want a plan.

The cheeky response to this is that in a democracy, this wouldn’t happen. Now, the US is a democracy. Cuomo has to stand for election every four years. The worst infrastructure disasters tend to be in countries that are authoritarian through and through: Russia’s elevated winter Olympics costs in Sochi and Qatar’s human rights abuses in the World Cup preparations are the two biggest recent examples. But democracies with insufficient checks on political power are susceptible to this as well. This is common in the third world, where corruption is more common – hence the abuses of the World Cup last summer, in a solidly democratic country – but can also happen in developed countries with democratic deficits.

Usually, the phrase democratic deficit refers to the EU, and by analogy other supranational organizations. But in the US, it’s a useful framework for thinking of local and state governments. Rick Scott, Scott Walker, and John Kasich needed nobody’s approval to reject federal funding for intercity rail. Chris Christie did not need anyone’s approval to cancel ARC, or to cause traffic jams in retribution against a mayor who refused to endorse him; in a recent article in New York YIMBY, defending the cancellation of ARC as originally proposed, I made sure to take multiple barbs at Christie, just to avoid playing into the agenda of canceling ARC to posture about government waste while diverting rail money to the New Jersey Turnpike.

Cuomo’s power is if anything even greater: the New York state government works by a three men in a room model, in which the governor, the speaker of the State Assembly (just indicted for corruption), and the majority leader in the State Senate (currently relatively powerless and dependent on Cuomo) wield all practical power. In such a system, Cuomo does not have the power to shoot protesters, thankfully, but does have the power to propose megaprojects that glorify him, without a broad discussion with stakeholders, in which the MTA’s long-term expansion plans and cost-benefit ratios would come into play.

Last year, in writing about elite infrastructure projects that are not about meeting a service need, I noted that talking about such projects in terms of cost-effectiveness is moot, because they were never intended to be about benefiting the wider public. We could discuss where to spend money on transit in New York in the way that would benefit the largest number of riders. We could even discuss what the optimal way of connecting to LaGuardia is, before comparing the best connection with non-airport projects to see where it should lie on the list of future expansions. But it would be pointless, because Cuomo is not interested in spending money on benefiting the largest number of riders; he frankly does not care about transit riders. When the time came to support transit riders, for example in signing a lockbox bill guaranteeing that money the state government had promised the MTA would indeed go to the MTA, he vetoed the bill instead.

In such a climate, as soon as we talk about tweaks to Cuomo’s plan, Cuomo’s already won; whatever happens, he will reap the credit, and use it to buy political capital to keep building unnecessary megaprojects. Even trying to make the best of a bad situation by making the airport connector better is of little use, since Cuomo will support the plan that maximizes his political capital and not the one that maximizes transit usage even within such constraints as “must serve LaGuardia.”

This is evident in his response to criticism among transit activists. After listing the many pundits and activists who oppose the plan, Capital New York included a response from the governor’s office, which said, in so many words, “our plan is better because it doesn’t go through populated neighborhoods, where there would be NIMBYs.” What those of us who want good transit view as a feature – connecting to underserved neighborhoods and not just to the airport – Cuomo regards as a bug. A plan that included additional stops in Astoria might well attract community support, while still offering much faster trip times to Manhattan because of the direct route, but would rely on non-airport ridership, which Cuomo doesn’t care about, to keep the cost per rider reasonable.

Because of this disconnect between what would work for transit users and what would work for Cuomo, the only reasonable answer to the plan is a simple no, which should be said as sharply as possible. No working with the proposal: it’s terrible, a true stone soup. No tweaks: Cuomo wouldn’t want any ingredients that would improve the soup, and would insist on keeping the stone in anyway. (He doesn’t have to eat it, he doesn’t use transit either way.) And, within the parameters of a transit conversation in which people are desperate to see expansions, no discussion that validates Cuomo’s original plan.

Update 7/28: in a joint announcement with Joe Biden, Cuomo has just announced $4 billion in airport improvements at LaGuardia, bundling the rail connector into the larger projects. I have nothing to add that I didn’t already cover in this post and in my older post about elite infrastructure investments.

Who Rides Commuter Rail?

I’ve had an argument in comments with the author of Purple City about who commuter rail should serve. He’s argued before that cities should make sure outer suburbanites can get to the center via express commuter rail, and I will add that American cities do do that, and orient commuter rail too much around the needs of peak-hour outer suburbanites. Insofar as I think cities should have commuter rail there’s no disagreement, but what I think they do wrong is focusing too much on the peak. The two practices in contention are the low off-peak frequency (for example, Metra’s Union Pacific-North Line, which has no freight to speak of, has worse than hourly off-peak service), and the stop distribution, which has trains making few or no stops in the city proper.

The common thread of these two practices is that they optimize one variable: peak travel time for a suburban commuter to the CBD. This neglects other sources of ridership on commuter rail, which are suppressed in the US but significant in countries with more modern operating practices. I will contrast the peak-focused approach with a rapid transit approach, using examples that I believe will show that the latter is bound to get far more ridership, even in the suburbs.

First, let us imagine a contrasting system, one in which North American commuter rail looks more like an RER, an S-Bahn, or a Japanese commuter rail network. Such a system will have the following features:

1. Relatively consistent stopping pattern. The busier lines may have local and express trains, but the express trains will stop at the same major stops. Local trains will make all local stops over a fairly wide stretch.

2. Low ratio of peak to off-peak frequency, in the vicinity of 2:1 or even less. In a major city like Chicago or New York, a line that can’t support half-hourly service all day, at a bare minimum, will likely have no service at all; the only exceptions I can think of are services at range so long they’re practically intercity, like New York-Hamptons or New York-Allentown.

3. An urban stopping pattern that’s not too express. If there’s a parallel subway then it’s okay to have a somewhat wider stop spacing than in the inner suburbs beyond the subway’s range, but still closer to the 2-3 km range than the 4-5 km range of Metra.

If it’s possible to do so technologically, then the commuter line may be interlined with a subway line, even. This is usually hypothetical, since subways and commuter trains, where both exist, are almost always technologically incompatible; Tokyo and Seoul are the two major exceptions, with London a borderline case. However, it’s useful to consider such hypothetical cases, to examine what would happen to train service. I will consider two such cases: having Vancouver’s Evergreen Line take over West Coast Express (the original argument), and having Boston’s Red Line take over Old Colony Lines. Neither situation is technologically possible, even ignoring FRA and Transport Canada regulations, as both Boston and Vancouver build subway tunnels for much smaller trains than run on the mainline, but this discussion may be useful in cases where a takeover is feasible, such as when the commuter line is an isolated branch. I prefer to discuss the hypotheticals since the two examples in question are purer examples of priorities: outer-suburban peak service, or rapid transit-style service.

Vancouver

Vancouver’s rail service consists of the SkyTrain network, which gets about 400,000 weekday riders, and the West Coast Express, a peak-only commuter rail network running 5 trains per day per direction, with 11,000 weekday riders. SkyTrain’s under-construction Evergreen Line will intersect the West Coast Express at Port Moody and Coquitlam, and then serve more stations in Coquitlam off the mainline, while the WCE continues much farther to the east, into the Vancouver exurbs. The WCE connects Port Moody to Waterfront in 25 minutes and Coquitlam in 30 minutes; the Evergreen Line is projected to take 33 and 38 minutes respectively, with a transfer at Broadway/Commercial. Despite the slower service, the much higher frequency, all-day service, and connections to more of the Vancouver metro area win: the projected ridership for the Evergreen Line is about 23 million a year (see Table 2 on PDF-p. 4 here), which corresponds to about 75,000 per weekday.

Now, what’s in contention is whether it would be wise to have the same treatment at WCE stations farther east. The potential ridership at those stations is lower since they’re in less built-up areas, so it is likely cost-ineffective to build an Evergreen Line branch along the Canadian Pacific mainline and have it replace the WCE, but if such a line were built, it would most likely have the same effect on travel times: people would have to transfer at Broadway/Commercial, and not including the transfer time take 8 minutes more to get to Waterfront. The eastern end of the line, Mission, has 75-minute service now, and this would change to 83-minute service plus a transfer.

I claim that Mission residents would still take the train more often if it were 8 minutes lower. The reason is simple: as a proportion of overall travel time, the 8 minutes are more important to a 25-minute Port Moody commuter than to a 75-minute Mission commuter. Mission commuters live farther out, so they’re somewhat less likely to care about service to various neighborhoods along the way, but they’re even less likely to care about 8 minutes. They also are less likely to care about very high frequency, since their trips are longer, but they do care about service availability all day, even if they’d be okay with half-hourly service. Moreover, the Evergreen Line will connect to secondary nodes like Metrotown better than the WCE does, and eventually have direct service to Central Broadway and UBC, both of which draw commuters from the entire region.

In the present, the WCE works as a placeholder – it’s possible to reduce staffing and improve turnaround times to allow off-peak service, but there’s too little population east of Coquitlam to justify a SkyTrain extension, and so far population growth is fastest in inner-suburban Port Moody and Surrey (see here and here) and not east of Coquitlam. In the future, if those areas grow then it will make sense to replace the WCE with SkyTrain. WCE upgrades are unlikely – adding infill stations is practically impossible, as the line hugs an active port, with no good station sites. While SkyTrain’s driverless configuration keeps operating expenses down, it makes it impossible to extend branches to the suburbs cheaply by running them at-grade and in mixed traffic with freight.

Boston

Several of Boston’s subway branches are parallel to extant or closed commuter lines. The Orange Line runs alongside the Northeast Corridor to Forest Hills, the Blue Line took over parts of the narrow-gauge Boston, Revere Beach and Lynn Railroad, the Green Line D Branch took over a commuter rail loop used by the Boston and Albany, and the Red Line took over a New Haven Railroad branch line to Ashmont and runs alongside the Old Colony Lines to Braintree. At the time the Braintree extension opened the Old Colony Lines were closed for passenger service, but they have been since reopened, running from Braintree to South Station with just one stop in between, either JFK-UMass or Quincy Center (never both, except on trains that skip Braintree); off-peak frequency is about every two hours on each of two lines, and with some off-peak trains skipping Braintree, service to Braintree is worse than hourly. The Red Line takes 26-27 minutes to go from Braintree to South Station, the Old Colony Lines take 19-21 minutes.

As is projected in Vancouver, ridership on the Red Line is much higher: according to the 2014 Blue Book, on PDF-pp. 14 and 74, the busiest MBTA commuter rail station, Providence, gets 2,325 riders per weekday and the busiest Old Colony station, Bridgewater, gets only 1,036, while the Braintree extension’s five stops get 6,975, 4,624, 8,655 (Quincy Center), 4,785, and 5,122 (Braintree). Those five stops get 30,000 riders between them, meaning 60,000 since it’s unlikely people ride internally on the extension; this is nearly half the entire MBTA commuter rail ridership, and three times the ridership on the Old Colony Lines (counting Greenbush, which diverges at Quincy, as a third line).

As in Vancouver, I claim that a Red Line extension taking over the Old Colony Lines would have much higher ridership. Of course the frequency per line, already middling since the Braintree extension is a branch, would not be very good; but at the range of the suburbs served by these lines, half the current frequency of the Red Line, giving about 20 minutes at the peak and 30 off-peak, is enough, and is a massive improvement over multi-hour headways. The extra 5-8 minutes of travel times matter less as one moves farther out, again; travel time to South Station from the first Old Colony stations past Braintree, South Weymouth and Holbrook/Randolph, is 28 minutes, about the same as from Braintree on the Red Line, and those two stations have a bit more than 500 weekday riders each.

Moreover, the Red Line has something the commuter trains don’t: service to multiple centers within the inner Boston region. Downtown Crossing is closer to most jobs than South Station, saving people the walk. Cambridge is a major job center in its own right (it has more jobs than any New England city except Boston, ahead of Providence, Worcester, and Hartford). Back Bay is a bit more accessible via the Orange Line at Downtown Crossing or the Green Line at Park Street than via commuter rail at South Station.

Like SkyTrain, the Red Line can’t run on mainline rail tracks, and there is not enough population to justify an extension, nor enough population growth in New England for such an extension to ever pencil out. However, it’s possible to modernize commuter rail, as I have written before. This would not provide direct service to Downtown Crossing or Cambridge, but could provide cross-platform transfers to Back Bay, decent frequency all day, and, since regional EMUs can have very good performance characteristics, much higher average speeds than with today’s slow diesel locomotives even if trains make more stops.

General Remarks

The examples of Boston and Vancouver’s ridership patterns suggest that it’s okay to sacrifice speed to provide coherent service. It’s worth noting here that the bulk of present-day ridership on North American commuter rail would not benefit too much from such sacrifice. North American commuter rail provides awful service in the off-peak or to non-CBD destinations: even the Newark CBD, relatively well-served by New Jersey Transit, has a 26% mode share as a job center as of 2000, as per an Alan Voorhees Transportation Center report called Informed Intuition (PDF-p. 13). There’s a huge amount of latent ridership on North American commuter rail, which is why rapid transit gets so much more ridership than peak-focused commuter rail.

This doesn’t change much at different ranges of distance from the center. The few minutes saved by expressing through the city to the CBD matter a great deal to the suburbs right beyond city limits, but those innermost suburbs are precisely the ones that could make the most use of service to multiple city nodes. Farther out, where commuters to the city tend to be more likely to be working at the CBD, since it is more specialized than most secondary nodes, frequency and service to everywhere matter less, but the extra few minutes matter even less.

However, since present-day riders are precisely the narrow slice of potential users who are okay with the current setup, they have the potential to engage in NIMBY protests against any attempt at modernization. Why change what works for them? This is why Long Island representatives oppose such modernization attempts as letting Metro-North access Penn Station; it’s entirely a turf war. Even reforms that do not degrade trip times to the CBD are unlikely in this political situation, for example mode-neutral fares: the people paying premium fare to ride the LIRR or (to some extent) Metra are the ones who are okay with paying this fare, and who may object to increased train crowding coming from lower fares.

Judging by the ridership multiple between the Evergreen Line and WCE, there are likely to be a few million weekday rides coming out of Eastern Queens and Long Island if the LIRR is modernized, but those are not the Manhattan-bound commuters who dominate the discussion today. Instead, they are people who have gotten used to unusable commuter rail, and drive to work, or take long bus-subway commutes to avoid paying higher fares. They do not seem like a significant source of regional rail ridership because they are not current riders (or they ride local transit instead), but they are precisely what makes the difference between the low ridership of every North American commuter rail system and the higher ridership of many European systems.

Mixing Circumferential and Radial Transit

Nearly all rapid transit lines belong to one of two categories: radial lines (a large majority), which connect city center with outlying neighborhoods or suburbs; and circumferential lines (a minority), which go around city center and often serve secondary centers and usually intersect all or nearly all radial lines perpendicularly, such as Paris’s Lines 2 and 6, Moscow’s Circle Line, Seoul’s Line 2, New York’s G train, and Shanghai’s Line 4. In this post, I’m going to discuss an uncommon third category, that of lines that combine circumferential and radial functions: they go toward city center, like a radial line, but then change direction and become circumferential. The G train in New York was like this until 2001, and Line 3 in Shanghai is like this today. This is apropos a proposal by a team Penn Design graduate students to build a variant of Triboro RX in New York that combines Triboro’s circumferential orientation with a radial commuter line. I believe such mixed lines are a recipe for low ridership and strained transfer points, and the Penn Design proposal is inferior to the original Triboro proposal.

First, some details about the mixed lines in question. The example most accessible to most readers is the historical G train in New York. When it first opened in the 1930s as part of the IND, it was designed to both connect Brooklyn and Queens without going through Manhattan and provide local service along radial lines, running alongside express trains that would serve Manhattan. Thus the northern half of the G ran under Queens Boulevard as a local, while the E and F trains provided express service and went to Manhattan. From the start, this arrangement was unstable. Demand for service to Manhattan was much greater than to Brooklyn, so people riding the G inbound changed to the E or F at the first express station after the one they boarded. With overcrowded express trains and undercrowded local ones, the Transit Authority was compelled to build a track connection in 1955 to add a Manhattan-bound local service, and to build a second track connection in 2001 to add another Manhattan-bound local train and remove the G from Queens Boulevard entirely.

In Shanghai, Line 3 was built as an (almost) entirely above-ground line, interlined for part of the way with the circular Line 4. The northern half of Line 3 is radial, running parallel to the overcrowded Line 1. However, where Line 1 enters the traditional center and serves People’s Square, Line 3 swerves west to go around it (missing Lujiazui, the new high-rise CBD to the east of People’s Square), interlining with Line 4, and leaving the loop southward to intersect Line 1 again at Shanghai South Railway Station. Its ridership disappoints not only by the standards of Line 1, but also by those of Line 4: 642,000 on 2014/4/30, the system’s busiest day, compared with 1,384,000 on Line 1 and 907,000 on Line 4. Line 6, which likewise combines a radial function at its northern end with a circumferential one at its center, serving Century Avenue but not Lujiazui or People’s Square, has even lower ridership, 376,000, although this is several times the original projection.

There’s a discussion on Human Transit, in which consensus is that the best circumferential lines connect secondary activity nodes that generate trips in their own right. Now, the G train connects Downtown Brooklyn (the largest business district in New York outside Manhattan) with Long Island City (one of the business districts of Queens), but it lacks the other positive feature of circumferential lines: transfers to the radial lines, to allow one-transfer trips from anywhere to those secondary nodes. The G has good transfers only to other IND lines, and at the Queens end, its transfer to the Queens Boulevard trains was cut in 2001 since, for operational reasons, it was cut not to its old junction with the E and F (Queens Plaza) but one station short (Court Square). Other G transfers are very recent and require a considerable amount of walking.

In contrast to the underperforming G, circumferential lines that both connect important activity nodes and have plenty of radial transfers are backbones of their cities’ transit systems. Shanghai’s Line 4 is fairly busy as noted above. Seoul’s Line 2 is according to a forum post the busiest in the system. Paris’s Lines 2 and 6 are only about average in ridership but combined would be the second busiest after Line 1 (and per route-km are third and fourth, only behind Lines 1 and 4, but are only narrowly ahead of many other lines). The juxtaposition of Shanghai’s Lines 3 and 4 in particular suggests that subway lines shouldn’t try to mix radial and circumferential functions.

Let us go back to the impetus for the post, Triboro RX. The proposal is to largely use existing freight rail lines, all of which are lightly used and could be turned over to the subway, to provide a semicircular line connecting nodes of activity in the Bronx, Queens, and Brooklyn. Because of the focus on using an existing right-of-way to reduce costs, the line misses the most important nodes in Brooklyn and Queens, which are served by the G in any case. However, it passes within half a kilometer of the Hub in the Bronx and, via a short greenfield tunnel, connects to Yankee Stadium, the Bronx’s busiest subway station; it also connects to Brooklyn College and 74th Street/Broadway in Queens, both busy stations if not as central as Downtown Brooklyn or Long Island City. Moreover, it provides direct Bronx-Queens service, which in the existing system requires circuitous routes through Manhattan with difficult transfers, and has reasonable transfers to nearly all subway lines. At the end, the lack of service to Downtown Brooklyn ensures it cannot be a very well-patronized line, but as the right-of-way is almost entirely in place, its cost per rider could be quite low.

In contrast, the Penn Design proposal, called Crossboro, severs the connection to the Hub and Yankee Stadium, and replaces it with service along the Northeast Corridor to Coop City, making sparse stops, at the same locations Metro-North plans to for Penn Station Access; this is 4 stops in 10 km in the Bronx, compared with stops spaced roughly every 800 meters in Queens and Brooklyn, as in the original proposal. The trains would be certified for mainline operation, on the model of the London Overground, rather than segregated from mainline traffic.

The problem with the Crossboro idea is essentially the same as that of the G train until 2001. Most riders at the four Bronx stops are interested in getting to Manhattan, and not to the neighborhoods served by Crossboro, so they’d look for transfer opportunities. The only such opportunity in the Bronx is at Hunts Point, to the 6, which unlike the E and F on Queens Boulevard runs local and provides slow service to Manhattan. With the extra transfer, there is no advantage to Bronx riders over continuing to walk or take the bus to the 2, 5, and 6 trains to Manhattan. Moreover, because of the poor transfers within the Bronx, it’s impossible to use the line to connect from Queens to anywhere in the western half of the Bronx, including Yankee Stadium and the Hub: there’s a connection only to the 6, and none to the 2, 4, 5, or B/D, or to Metro-North.

The principle in action here is that, especially when there are no compelling destinations, it’s critical to make sure the line provides connectivity between large regions. This means connecting to all or almost all radial lines in a region well-served by radial subways but poorly served by preexisting circumferential ones. Not including the 1, which no proposal connects to, the Bronx has five subway lines, all providing radial service to Manhattan; it is a feature of Triboro that it connects to all five (though the connection to the 2/5 requires a long walk), ensuring that people from nearly everywhere in the Bronx can use the line to get to its destinations in Queens and Brooklyn with one transfer. To get from anywhere to anywhere would require two transfers, but to get from a random station in the Bronx to one in Queens or Brooklyn often already requires two transfers, usually at busy Manhattan stations that are out of the way for the crosstown traveler.

Mixing radial and circumferential service interferes with this principle, since the radial component has to come at the expense of completing the circle (or semicircle in a geographically-constrained city like New York). Thus, it’s harder to use the line to get to a large enough variety of points of interest to make up for the fact that it misses the city’s most important destinations. Of course, such a line is also wanting as a radial line, since it misses the center. Thus, ridership underperforms, and the line usually fails to achieve its stated purpose.

New York Regional Rail: the Central Segments

I’ve written a lot of articles over the years about what should be done with regional rail in the New York area, focusing either on the overall shape of the system (as on The Transport Politic) or on specific aspects of the central links (as in past posts here). I’d like to synthesize these ideas into one coherent proposal. Unlike my posts on The Transport Politic, I’m going to pay relatively little attention to how to match branches for ridership, but more attention to what to do in a central region consisting of the city proper, New Jersey as far as Newark, and New Rochelle. I will also indicate things that can be done to keep construction costs under control for a plan that includes 30 kilometers of urban and underwater tunnel, about six times as much as the planned tunnels across the Hudson.

The Principles, Restated

The most important principle for infrastructure planning in developed countries is organization before electronics before concrete. In New York, it’s possible to squeeze some extra capacity out of the first two: notably, the LIRR and Amtrak together only run about 40 trains per hour into Penn Station from the east on four tracks, whereas the maximum capacity is about 50, and this is before trains are diverted to the East Side Access tunnels to Grand Central. The LIRR’s bottleneck is not the East River Tunnels, but the platforms at Penn Station, and this means it’s possible to use improved operations, including through-running, to squeeze extra capacity even before East Side Access opens.

However, the biggest bottleneck in the region is from the west, across the Hudson, and there, present traffic peaks at 24-25 trains per hour on just two tracks. I know of limiting cases in which mainline operations achieve about 30, using moving-block signaling on captive tracks (e.g. the RER A, which shares tracks with nothing else in its central segment), with one example that uses fixed blocks (the shared RER B and D tunnel achieves 32). Here, concrete is unavoidable, so new tunnels are required. In addition, providing service to more points than Penn Station, or Grand Central for commuter lines connected to it, requires new tunnels as well.

However, this new infrastructure should be built economically. The posts I linked to in the initial paragraph of this post provide some ideas, including the use of large-diameter tunnel boring machines to reduce station construction costs, and the use of the existing station cavern at Penn Station. This should be paired with seamless fare and schedule integration, including through-routing, and a fleet replacement plan to get rid of locomotive-hauled trains and replace them with EMUs (electrifying unelectrified branches as needed).

Subject to the requirement for new infrastructure, New York should remember that it’s a major city, and as such, it’s capable of supporting multiple independent commuter lines. Paris has five RER lines, of which only the B and D share tracks, and only between one pair of stations, on top of several major commuter lines disconnected from the RER network. It’s better to keep the map relatively coherent, so that one central trunk will split into several outer branches, but nearly all outer branches will feed into consistent central trunks. (As an example, the London Underground’s deep-level lines’ branching is coherent, while the New York subway’s mostly isn’t, with the E, F, M, and R trains running on what’s technically a branch and then diverging to three different Manhattan trunks.) This simplifies the junctions that need to be built just outside the city core, and also makes the network easier to remember.

The Tunnels

There should be a new pair of tunnels between New Jersey and Penn Station, parallel to and south of the existing tunnels. Those tunnels should then continue to Grand Central. This is the core of ARC Alternative G, which was removed from consideration in the original ARC project for reasons that were never explained adequately (Stephen Smith has been making freedom of information requests for years). However, unlike Alt G, it should not include new railyards in Manhattan, as those belong in areas where land is cheaper, nor should it include a loop for trains from the Erie lines to get to Penn Station.

The lynchpin of the plan is not the tunnels to Penn Station, which are already on the political radar in the form of the Gateway Project, albeit at a large multiple of an acceptable cost, due to such frills as new Penn Station tracks. Rather, it’s a new set of tunnels, meeting at Lower Manhattan in the vicinity of Fulton Street, going in four directions: north to Grand Central, south to Staten Island under Lower New York Bay, northwest to New Jersey via the Erie Railroad’s old Pavonia terminal, and southeast to Brooklyn to the Flatbush Avenue LIRR station. Using a double-O-tube large-diameter TBM, the Fulton Street station should feature cross-platform transfers, large banks of escalators to the street, and, to reduce costs, no station structures outside the tunneled station, putting timetables and ticket-vending machines on the street. All connections should be to Grand Central’s existing station and not the new East Side Access cavern, as the cavern leads only to the LIRR, which is already connected with both Penn Station and Flatbush Avenue. The existing tracks connect to Metro-North, which is not.

A possible additional tunnel in the far future would connect Hoboken with Grand Central’s new cavern, via Union Square. This is only in case the existing lines become congested. Current commute patterns make such congestion very unlikely, but things could change if, as a result of the new capacity, more people choose to live in suburban North Jersey and work in Manhattan.

The Network

There should be five lines running through Manhattan, without any track-sharing between them, and one using East Side Access and terminating in Manhattan. I am going to try using consistent numbering, different from the order I used in my posts on The Transport Politic, in order to group the lines using Penn Station and the lines to Lower Manhattan separately.

Line 1 is the existing mainline. Its inner route goes from Secaucus Junction to Sunnyside Junction, via the existing tunnels to Penn Station. Intercity trains use it (and should continue doing so), but most traffic will always be on commuter rail. Beyond Secaucus, trains can go to either the Northeast Corridor or the Morris and Essex Lines; to simplify junctions, most trains should use the Northeast Corridor (including the Raritan Valley Line, which splits past Newark). Beyond Sunnyside, they can go to the LIRR or the Northeast Corridor; to ensure adequate capacity for intercity trains while still providing service to the eastern Bronx, trains should use a mixture; in the long run, four-tracking everything north of Hell Gate Bridge will be necessary. It may be best to dedicate Port Washington trains to this line. At Penn Station, it uses middle-numbered tracks.

Line 2 uses the new tunnels to Penn Station and Grand Central. Its inner route goes from Secaucus to Penn Station, Grand Central, and Harlem-125th Street, splitting into branches thereafter. Most trains should go to the New Haven Line, since Line 1 could never provide adequate traffic for it; the rest should go to the Hudson Line – see below for Line 3. At the New Jersey end, it should run to a mixture of Northeast Corridor trains (including to the North Jersey Shore and Raritan Valley) and Morris and Essex trains, as required by demand. At Penn Station, it uses low-numbered tracks, potentially just 1-4. I expect it to be the most crowded, because of the service to both primary Midtown Manhattan stations.

Line 3 uses the Empire Connection, realigned tunnels to Penn Station, and the northern pair of the East River Tunnels to reach the LIRR. Its inner route goes from Yonkers to Penn Station and thence to Sunnyside. Intercity trains to Upstate New York use this line, but there are fewer of them than on the Northeast Corridor. Beyond Yonkers it can only go on the Hudson Line, so most Hudson Line trains should use it rather than Line 2. At the LIRR end it should run alongside trains to the East Side Access tunnel; as the splits are far to the east of Sunnyside, it may be prudent to have each branch serve both it and East Side Access, but in either case, timed East Side Access/Line 1 transfers at Sunnyside are necessary. At Penn Station, it uses high-numbered tracks. I expect it to be the least crowded, since to the west it only reaches one commuter line, one whose present traffic is moderate.

Line 4 is the main north-south line, from Staten Island (both the existing Staten Island Railway and the North Shore Branch) through the underwater tunnel to Fulton Street, Grand Central, and Metro-North. North of Harlem-125th Street, it can connect to any line, but I think the Harlem Line is the most coherent, as the only Metro-North line that is not needed for lines that don’t go to Grand Central. I expect it to be very crowded with inner-suburban and outer-urban traffic, as it serves Staten Island and underserved neighborhoods of the Bronx and the suburbs to its immediate north.

Line 5 is the combination of the Erie Lines, and possibly also the Northern Branch and the West Shore Line, and the LIRR’s Atlantic Branch, via Pavonia and Flatbush. For interlocking simplicity, all trains should go to one or two lines beyond Jamaica, ideally the Atlantic and Montauk Lines (the existing turnouts already favor trains from the Brooklyn Atlantic Branch continuing along the branch to Far Rockaway and Long Beach), leaving the Main Line to Line 3 and East Side Access. As there are five possible branches in New Jersey – the Northern Branch, the West Shore Line, the Pascack Valley Line, the Bergen County Line, and the Erie Main Line – frequency would be limited if all were used, so it may be best to choose just three.

Here is an unlabeled map of the five lines, with only inner branches shown; the decision of what station to terminate branches at has nothing to do with the desired service pattern, and is purely illustrative.

A potential Line 6 would take in all Morris and Essex lines, go to Hoboken, cross into Manhattan via a new tunnel with an extra stop at Union Square and then go to Grand Central and East Side Access; as discussed above, it’s omitted due to its very long-term nature.

Penn Station

I have discussed what to do with the Fulton Street Station. Penn Station is more complicated. The easiest thing to do is nothing, beyond new tunnels. There would be many platform tracks, two per access track for Line 2 and more than two for Lines 1 and 3; Line 3 would involve difficult switching moves and slow speeds through the station. Line 1 is the most important priority for allowing intercity trains to serve the stations with few (ideally no) diverging moves at turnouts, to maintain speeds.

To avoid platform congestion, especially on Line 2, more staircases and escalators should be installed. This, however, clutters the narrow platforms.

The second possibility is to pave over tracks to widen the platforms. I vacillate between preferring paving over pairs of tracks to create very wide platforms, and paving over every other track to create wider platforms at which trains can open doors on both sides. Right now I lean toward the former, as it would allow reusing preexisting escalators: the platforms currently have single-direction escalators as they’re too narrow for an adjacent pair of escalators, one per direction, and merging two platforms would be the easiest way to allow wider escalator banks.

Unfortunately, on the line with the biggest platform crunch, Line 2, this would imply a single platform with two tracks serving two tunnel tracks, so that dwell times would limit capacity somewhat. This limit is not too sharp – 24 trains per hour are achieved at through-stations in many cities without additional tracks, with some limiting cases of 30 (such as the moving block signal-equipped RER A) – but it’s still a limit, and requires good timetable adherence departing the station. These are only commuter trains, which run shorter routes than intercity trains, but Line 2 is likely to involve some long-range commuter runs, as far as Trenton or Dover or New Haven. (Since Line 1 is the only one serving local Northeast Corridor stations in the Bronx, it should only get the local trains, while longer-range trains to New Haven should use Line 2.)

The most expansive solution is to rebuild the station’s track level. There is an RPA study Penn Design study in that direction. For optimal passenger usage, the two concourse levels would be replaced by one, and the station’s 21 tracks would be reduced to 12, facing six 15-meter-wide platforms; the platforms’ eastern ends would be shaved slightly, to allow longer curve radii heading from the Lines 2 and 3 tunnels with simple turnouts, each tunnel track turning into two station tracks facing the same platform. In principle, it can be sequenced to shut down parts of the station in succession: first the southern tracks (New Jersey trains would be immediately interlined with Northeast Corridor and LIRR trains for a combination of Lines 1 and 2), then the northern tracks (the LIRR would have East Side Access by then), and finally the remainder of the central tracks. The bulk of the work on the central track could be done in conjunction, first removing the platform between the existing tracks 11 and 12 and then realigning tracks from the center outward.

I want to clarify that I do not support the most expansive solution, as it is likely to cost billions of dollars. It would create a nice Penn Station for train travelers. Those 15-meter platforms could have 6 escalators side by side with not too much obstruction, and 4 with practically none (the widest escalator is 1.6 meters wide outer end to outer end, with 1 meter used for the moving stairs). Reducing the two concourses to one would allow taller ceilings throughout, and redesigns of passageways for maximum passenger throughput. The only problem: it would be extremely expensive.

I bring this up only because the Municipal Arts Society and the RPA have teamed to propose a multi-billion dollar remake of Penn Station above track level, with high aesthetic value and zero transportation value. In addition, Amtrak wants to move its passenger facilities one block west, in the wrong direction, which has negative transportation value. If there has to be a redo of the station, it might as well be one that improves it at track level as well, rather than just making it pretty from the outside.

Phasing and Costs

The ideal phasing is “as soon as money becomes available.” There is a tendency in the US to be overly cautious about everything and chop projects into little pieces, in the name of prudence. It’s always easy to show one’s moderation by chopping a fixed amount of money from every proposal (quintessential moderate Senator Olympia Snowe was famous for this) and by funding many projects by small amounts. These small projects then fail because of reduced network effects or sometimes higher costs due to smaller orders.

The tunnels I proposed in this post sum to about 30 kilometers. These 30 kilometers are objectively difficult to build. The tunnels for Lines 4 and 5 of this proposal go under wide rivers and a bay, and once they reach Manhattan land they have to go under the entire Lower Manhattan subway network. Half a billion dollars per kilometer would be a good deal: Crossrail is more than a billion dollars per double-track tunnel kilometer, assuming there is nothing to build except tunnels (which is far from true), while Crossrail 2’s cost range is $600-850 million per km (see also my first comment in the link). London is a high-construction cost city, but New York is even higher-cost; building a line for London’s costs would be a major achievement for New York.

Bear in mind that Amtrak thinks the Gateway Project alone would be $16 billion. When I propose to build an entire regional rail network for perhaps $20 billion (in 2010 dollars, not year-of-expenditure dollars), based on what it would cost in other cities, I am not taking into account the bloat that leads to high costs in New York. At the per-km costs Amtrak thinks are appropriate for what would be one of the simpler tunneling projects for this system, this is plain unaffordable.

Still, precisely because of the network effects, and because this plan neatly separates branches of the existing commuter rail system, it should be proposed all at once. If it’s expensive then it will also be delayed; it’s better to have six mainline rail tracks under the lower Hudson by midcentury, than to have four and then realize there’s a capacity crunch and six tracks are required after all. Of course it’s best if everything is in place by the late 2020s, on the schedule of the Grand Paris Express. But the point is that longer project latency encourages bigger rather than smaller plans. The Line 2 tunnel, by whatever name, is still the most important priority, but the phasing then becomes “whenever it can be designed and built.”

The lower-end cost I’m proposing is for a project without any frills. It includes a bare minimum touch for Penn Station – simpler interlockings at places and some extra access points, but no more. It includes no Sunnyside decking or other redevelopment, which should be funded separately in any case. (When people build highways, do their projected cost figures ever include the construction of the suburban subdivisions they’d sprout?) It doesn’t include electrification of branches, although that is cheap enough as to be well within the uncertainty in even a first-order estimate. It doesn’t even include rolling stock, although the large preexisting fleet of decent EMUs means there’s no need for immediate fleet replacement as on the MBTA and other diesel-hauled railroads.

The only thing this project does include is more paths for more commuter trains to serve Manhattan and other regional job centers.

Quick Note: High Third-World Construction Cost Examples

Dhaka, the world’s poorest megacity (at least until Kinshasa crosses 10 million and qualifies as a megacity), is building a metro system. Using Japanese financing and Indian consultants, it is planning to build a multi-line system, and getting bids for the first line. This line is going to be elevated, and 20-21 kilometers long; construction costs are 220 billion takas, which is $2.8 billion in exchange rate terms and about $8.5 billion in PPP terms.based on the 2013 conversion factor here. This is a bit more than $400 million per kilometer, which is high for a fully underground line, let alone an elevated line.

Jakarta, which is much richer, but still third-world (Indonesia is slightly poorer than China, as of 2014), is building a metro as well. Its first line’s first phase is mixed underground and above-ground: 15.7 kilometers, of which 9.2 are underground. The cost is $1.4 billion, or about $4.2 billion after PPP conversion, giving $266 million per km, still on the high side for a 59% underground line, but nothing as extreme as in Dhaka.

It’s a reminder that poor countries aren’t just low-cost. Things usually are cheaper in the third world, but by a much smaller factor than the income difference. Bangladesh’s GDP per capita, before any PPP conversion, is about $1,000. It is cheaper than the US and Europe, but not by a factor of forty or fifty, but by a factor of about three. Three is an average – imported electronics cost about the same in exchange rate terms everywhere, whereas rent is much more sensitive to local wages – but, for rapid transit construction cost, the average turns out to level the entire difference between the first and third worlds. Some countries, like China, are still a bit cheaper than Europe, while others, like Bangladesh, overshoot.

Why Avoiding Stereotypes is Important (Hoisted from Comments)

In the transit-related forums I participate in, people know that the US builds subways at higher costs than all other countries, because I talk about it often. This feeds into various stereotypes Americans have of government effectiveness; Americans of many political stripes understand that there are serious problems with US governance, and compare the US negatively with certain countries that are famous for getting things done. Thomas Friedman periodically raves about China’s massive infrastructure investment; when he was secretary of transportation, Ray LaHood made the same praise, and connected this to Chinese authoritarianism, while saying that American democracy was still overall a better system. More recently, there’s been praise for Germany, or more generally Northern Europe, as a place with effective infrastructure investment (even as the actual state of German infrastructure is in decline). I was reminded of these stereotypes in the discussion of New York’s shrug-worthy reinvention report at Second Avenue Sagas: once again, the commenters praised the usual-suspect countries, and sometimes connected low construction costs with authoritarianism.

Several more examples from this month have made me notice that people overstate certain cultural differences, especially ones that are in line with stereotypes, such as Western individualism versus Asian collectivism or Northern European efficiency versus Southern European corruption. Cultures are far too diverse to be reduced to these oppositions, and this is especially true on the level of political subcultures, such as transit investment.

The reality is that the places with the lowest construction costs do not really match the stereotypes. Peruse my various posts about subway construction costs again: the main three, but also some of the side ones. Authoritarian countries like China and Egypt do not have unusually low construction costs. Countries with reputations for efficiency run the gamut: Scandinavia and Switzerland are relatively cheap, but Germany and the Netherlands are expensive, with some German projects needlessly expensive because of political influence over alignment choices. Labor costs seem to have a weak if any effect on construction costs: India, by far the poorest country on my lists, is fairly expensive to build in, and within the first world, low-income Naples has cheap construction but so do high-income Swiss cities and middle-to-high-income Milan. Culture in the sense of Samuel Huntington’s civilizations has a weak if any effect, again: there are multiple examples of subway lines built in the Western world, the Islamic world, and East Asia, and the cost differences within each bloc are far greater than the cost differences between the blocs.

I try to avoid giving explanations for these patterns of construction costs. If I knew for certain what caused them, I would not be blogging; I would be forming a consultancy and teaching New York and other high-cost cities how to build subways for less than $100 million per kilometer. I have seen two explanations by professionals. Manuel Melis Maynar, the former CEO of Madrid Metro, explained briefly how Madrid has the world’s lowest construction costs, in terms of design compromises, avoidance of outside consultants, and structuring bids based primarily on technical merit and not cost. And Paul Barter’s thesis explains Japan’s relative lack of urban freeways as a result of high land costs and a costly eminent domain process; this also explains the pattern of Japan’s high urban subway construction costs compared with relatively cheap Shinkansen tunneling (the 50% underground Shin-Aomori extension was only about $55 million per km).

The key here is that neither of these two particular explanations has anything to do with cultural stereotypes of the nations in question. When people think of Hispanic culture, many stereotypes come to mind, but none of them involves having hyper-competent local agencies designing subway systems with small in-house staffs. On the contrary, given the stereotype of Southern European corruption, an American or Northern European who was informed that Madrid Metro awarded contracts based on a combination of technical merit, speed, and cost, and did not use outside consultants, might conclude that it has a bloated in-house staff and that it uses the discretion of technical merit to favor the politically connected. Likewise, although Japan is notorious for the expense of its urban land, it does not have a reputation for strong property rights protections; Anglophone and Western supremacists take it for granted that the West has stronger property rights protections than East Asia, even if in reality English common law makes takings easier than Japanese law.

In addition to the thread on Second Avenue Sagas, in which I felt compelled to constantly defend Southern Europe’s record on building rail infrastructure efficiently, I was recently exposed to another set of stereotypes, in a four-week-old blog post by Andrew McAfee on Financial Times repeating all the usual American exceptionalist tropes of innovation. According to McAfee, the rise of the tech sector of Silicon Valley underscores how the US is going to keep winning the new global economy, giving Tesla as the prime example.

I have a simple bullshit detector for articles about innovation, especially in the tech sector: if they praise Israel’s entrepreneurial cultures, I know with a high degree of certainty that they’re familiar with too small a slice of the nation to be informed. The real Israel, even the upper middle-class slice that I grew up in, is a country at the bottom end of the first world, with Southern Italian average salaries (average household income per capita is about $14,000 a year in PPP terms, about half as high as in the US), with people who move to the US and are floored by the plenty they see at American supermarkets. It has a lot of tech workers, who function as a back office to Silicon Valley, and a handful of inventors who make exit and become rich; neither group is large enough to raise average salaries to proper first-world levels.

But McAfee’s wrongness goes well beyond the line about Israel. In a global economy with specialized regions, people tend to overvalue the sort of production that accords with their sense of identity, and this leads to either regional pride or nationalism. For a certain class of Anglo-American boosters, this is finance; New York and London are global financial centers, and this makes them worthier in this view than cities with different economic roles, such as Paris. McAfee belongs to the class that views the tech sector as the most important, and sees Silicon Valley’s wealth as superior. This is simply the modern equivalent of the 19th-century Manchester boosters’ denigration of Birmingham as a city that didn’t have Manchester’s culture of mass production of cotton, as described in The Economy of Cities; back then the boosters viewed the world as a giant factory, and today they view it as a giant smartphone app. The epitome of this is the overrating of Tesla, which is special only in that it’s made by someone with a background in online companies and not in the auto industry. Who needs the Tokyo rail system when there are luxury electric cars exciting the tech boosters?

As it happens, Europe has a lot of innovation in new fields – it’s not just Siemens making incremental industrial progress; it’s also the Human Brain Project. So do Japan and South Korea: McAfee brushes aside patent statistics, perhaps because Japan and South Korea have by far the highest numbers of patents per capita.

Now, to clarify, it’s possible to relate the US strength in online companies like Facebook to its business culture of superstars, which relates to individualism. In traditional manufacturing sectors, big businesses are built slowly, and require immense amounts of capital; in the tech sector, Mark Zuckerberg could start with a relatively low amount of capital, supplied by an angel investor like Peter Thiel on the strength of an already successful demonstration, and obtain a very large market share via network effects. However, this explanation still requires mediation via business culture. Quoting Marc Andreessen, McAfee lists four explanations, two of which do indeed involve business culture, but two of which play well into the European stereotype of American ignorance: great research universities, and rule of law and respect for contracts and property. Paris has some amazing research universities, judging by the intellectual achievements of their faculty, and as noted above, in some respects the Anglosphere actually has weaker property rights than Japan. But American tech boosters have learned that great universities lead to software and tech businesses, so if the Grandes Ecoles don’t have that then they can’t be that great, right? The national stereotype is stronger than the reality, just as with the insistence of many people in the transit infrastructure debate to talk about China and Northern Europe.

I’m reminded by a point that I made three months ago, in response to a proposal to move Silicon Valley to a growth-friendlier metro area like Houston. Facebook, Uber, and other hot Silicon Valley firms have a culture that works for their industry and that has led to useful inventions. This does not mean that the entire world has to operate like a Silicon Valley firm, nor does this mean that everything in the US operates like one. The same is true of other national stereotypes. The Spanish economy is weak, but happens to have a small segment, corresponding to infrastructure engineering and management, that works very well; other countries would be wise to copy this culture in the realm of infrastructure, and in nothing else, until it can be verified that the same principles work in other settings.

This sort of imitation, focusing on specific aspects of business culture in a particular industry, is harder than general handwaving about how to think like a German or Japanese business manager (a common trope in the 1980s and early 90s) or how to think like a Silicon Valley manager. It requires much more detailed knowledge of several different countries to make comparisons, and this is uncommon, since usually the sort of knowledge that leads to comparative analysis is broader and less specific. I certainly don’t have it – I only know the construction cost output, not the inputs that go into it. Even small mistakes are hazardous: it’s likely that the best performers’ cultures have many distinct features, of which some are crucial to their success but others are irrelevant, and it requires specialized knowledge to sort out which is which.

To add to my previous post about the MTA reinvention report, this is why I’m so disappointed in official efforts to improve American transit governance. The MTA and similar bodies have enough institutional clout and money to hire people who do understand the intricacies of various success stories abroad, and could make specific recommendations, which could appear small but could also be revolutionary. Commentators have to default to first-order information about costs, or to national stereotypes, but the MTA could have detailed knowledge about what’s needed. Instead, the MTA did nothing of the sort, and left the sweeping changes to mongers of stereotypes.

What is the MTA Reinventing, Anyway?

In the last few years New York’s MTA has gone through multiple cycles in which a new head talks of far-reaching reform, while only small incremental steps are taken. The latest is the MTA Transportation Reinvention Commission, which has just released a report detailing all the way the MTA could move forward. Capital New York has covered it and hosts the report in three parts. Despite the florid rhetoric of reinvention, the proposals contained in the report are small-scale, such as reducing waste heat in the tunnels and at the stations on PDF-pp. 43-44 of the first part. At first glance they seem interesting; they are also very far from the reinvention the MTA both needs and claims to be engaging in.

Construction costs are not addressed in the report. On PDF-p. 53 of the first part, it talks about the far-reaching suburban Grand Paris Express project for providing suburb-to-suburb rapid transit. It says nothing of the fact that this 200-km project is scheduled to cost about 27 billion euros in what appears to be today’s money, which is not much more than $150 million per km, about a tenth as much as New York’s subway construction. (Grand Paris Express is either mostly or fully underground, I am not sure.) The worst problem for transit in the New York area is that its construction costs are an order of magnitude too high, but this is not addressed in the report.

Instead of tackling this question, the report prefers to dwell on how to raise money. As is increasingly common in American cities, it proposes creative funding streams, on the last page of the first part and the first six pages of the second part: congestion pricing, cap-and-trade, parking fees, a development fund, value capture. With the exception of congestion pricing, an externality tax for which it makes sense for revenues to go to mitigation of congestion via alternative transportation, all of these suffer from the same problem: they are opaque and narrowly targeted, which turns them into slush funds for power brokers. It’s the same problem as the use of cap-and-trade in California.

One of the most fundamental inventions of modern government is the broad-based tax, on income or consumption. Premodern governments funded themselves out of tariffs and dedicated taxes on specific activities (as do third-world governments today), and this created a lot of economic distortion, since not all activities were equally taxed, and politically powerful actors could influence the system to not tax them. The transparent broad-based tax, deeded to general revenue through a democratic process, has to be spent efficiently, because there are many government departments that are looking for more money and have to argue why they should get it. Moreover, the tax affects nearly all voters, so that cutting the tax is another option the spending programs must compete with. The dedicated fund does neither. If the broad-based tax is the equivalent of market competition, a system of dedicated funds for various government programs is the equivalent of a cartel that divides the market into zones, with each cartel member enjoying a local monopoly. In this way there’s a difference between the hodgepodge of taxes the MTA levies and wants to levy and Ile-de-France’s dedicated 1.4-2.6% payroll tax: the payroll tax directly affects all Francilien workers and employers, and were it wasted, a right-wing liberal politician could win accolades by proposing to cut it, the way New York Republicans are attacking the smaller payroll tax used to fund the MTA.

The proposals of where to spend the money to be raised so opaquely are problematic as well. There is a set of reforms, based on best practices in Continental Europe and Japan, that every urban transit system in the first world should pursue, including in their original countries, where often only some of those aspects happen. These include proof-of-payment fare collection on buses, commuter trains, and all but the busiest subway systems; all-door boarding on buses; mode-neutral fares with free transfers; signal priority and bus lanes on all major bus routes, with physically separated lanes in the most congested parts; a coherent frequent bus network, and high off-peak frequency on all trains; and through-service on commuter rail lines that can be joined to create a coherent S-Bahn or RER system. As far as I can tell, the report ignores all of these, with the exception of the vague sentence, “outfitting local bus routes with SBS features,” which features are unspecified. Instead, new buzzwords like resiliency and redundancy appear throughout the report. Redundancy in particular is a substitute for reliability: the world’s busiest train lines are generally not redundant: if they have parallel alternatives those are relief lines or slower options, and a shutdown would result in a major disruption. Amtrak, too, looks for redundancy, even as the busiest intercity rail line in the world, the Tokaido Shinkansen, has no redundancy, and is only about to get some in the next few decades as JR Central builds the Chuo Shinkansen for relief and for higher speeds.

The only foreigners on the Commission are British, Canadian, and Colombian, which may have something to do with the indifference to best industry practices. Bogota is famous for its BRT system, leveraging its wide roads and low labor costs, and Canada and to a lesser extent the UK have the same problems as the US in terms of best industry practices. Swiss, French, German, Japanese, Spanish, and Korean members might have known better, and might also have been useful in understanding where exactly the cost problems of the US in general and New York in particular come from.

The final major problem with the report, in addition to the indifference to cost, the proposal for reactionary funding sources, and the ignorance of best industry practices, is the continued emphasis on a state of good repair. While a logical goal in the 1980s and 90s, when the MTA was coming off of decades of deferred maintenance, the continued pursuit of the maintenance backlog today raises questions of whether maintenance has been deferred more recently, and whether it is still deferred. More oversight of the MTA is needed, for which the best idea I can think of is changing the cycles of maintenance capital funding from five years, like the rest of the capital plan, to one year. Long-term investment should still be funded over the long term, but maintenance should be funded more regularly, and the backlog should be clarified each year, so that the public can see how each year the backlog is steadily filled while normal replacement continues. This makes it more difficult for MTA chiefs to propose a bold program, fund it by skimping on maintenance, and leave for their next job before the ruse is discovered.

I tag this post under both good categories (“good transit” and “good/interesting studies”) and bad ones (“incompetence” and “shoddy studies”) because there are a lot of good ideas in the report. But none of them rises to the level of reinvention, and even collectively, they represent incremental improvement, of the sort I’d expect of a city with a vigorous capital investment program and industry practices near the world’s cutting edge. New York has neither, and right now it needs to imitate the best performers first.

Height Limits: Still a Bad Idea

In a pair of recent articles on Strong Towns, Charles Marohn, best known in the urbanist community for introducing the term stroad (street+road) for a pedestrian-hostile arterial street, argues for height limits as a positive force for urbanism. He does not make the usual aesthetic argument that tall buildings are inherently unpleasant (“out of scale”), or the usual urbanist one that tall buildings lead to neighborhood decline; instead, he makes an economic argument that allowing tall buildings greatly raises land costs, and makes redevelopment of vacant lots less likely. He uses the following example:

Let’s say the local code allows [a] vacant lot to be developed as a one story strip mall, but nothing higher. If the strip mall is worth $500,000, then the vacant lot is going to be somewhere around $75,000.

Okay, but what if the development code allows that vacant lot to be developed as a sixteen story tower? If the tower is worth $20,000,000, then that vacant lot is going to fetch a much higher price, maybe as much $2.5 million.

You own that vacant lot. I come to you with an offer to buy it for $75,000. What are the odds you are going to sell it at that price when you look to the other side and see the same piece of property going for millions? Not very good.

In most cities, as Charles notes, there is not enough demand to redevelop every vacant lot as a high-rise, and therefore, if high-rises are permitted, a few vacant lots will be redeveloped as high-rises, while the rest remain vacant. This is not the case in large cities, which Charles specifically exempts in his article (see also Daniel Kay Hertz’s response), but part of the problem with the argument, as we will see, is that the boundary between large cities and small ones is fuzzy.

Let me now explain why this argument fails, like all the other arguments for zoning restrictions: it makes implicit assumptions on future uncertainty. The reason the vacant lot owners are not willing to sell for $75,000 is that they hope to get $2.5 million. In a stable market, with low enough population that most lots cannot fetch such a high price, the lot owners know that holding off on $75,000 offers is a gamble and that they are unlikely to ever get a higher offer. People have optimism bias and might overrate the probability that they’ll get the $2.5 million offer, but also have risk aversion; in most cases in economics, risk aversion dominates, so that safer assets cost more and have lower returns.

So when do we see holdouts? Risk aversion predicts that the probability of obtaining a $2.5 million offer should be higher than the total demand for new towers divided by the number of vacant lots. If we explicitly assume that the cost figures in Charles’ example, including land costs, are unchangeable, then this means vacant lot owners expect there to be more high-rise towers in the future, which comes out of growth regions. Charles’ example is based on Sarasota, which like most of Florida has high population growth.

The other possibility is regulatory uncertainty. In a competitive market, land costs are already as low as they can be while letting lot owners cash out on past investments. Developer profits are also as low as possible, and represent the developer’s wage for managerial work. However, zoning restrictions will greatly raise both figures, and a lot owner who expects future developments to brush up against the present zoning code can hold out until prices rise.

This is the danger of a system that is based on arbitrary rules (Charles proposes up to two floors or 1.5 times the average present height, whichever is higher), and arbitrary distinctions between small cities in which height restrictions are desirable and large cities in which they are not: these introduce political discretion in the details, which introduces additional uncertainty among lot owners. True windfalls usually involve the boundary between regulatory regimes, and this creates political incentive to game the system in order to be one of the few owners whose lots can be developed as high-rises. In contrast, once a ground rule is established that there is no zoning, such as in Houston, introducing zoning is difficult, even when there are rules that are zoning in all but name, such as parking minimums.

Once we get into the realm of cities with a large proportion of their lots developed, as Charles proposes, future development can only replace old development, and this introduces a key difference between new development and redevelopment: redevelopment requires buying out the preexisting property. If a two-floor building is replaced by a three-floor building, then the developer has to not only pay construction costs for three floors, but also buy out two floors, effectively paying for five floors. But the revenue is still only that of a three-floor building, which bids up effective costs by a factor of five thirds. The formula is that if it’s possible to multiply the total built-up area by a factor of x then the buy-out factor will raise the cost of each housing unit by a factor of 1 + 1/x.

This effect is why, in major cities, we usually see buildings replaced by much larger buildings: for example, a three- or four-floor Manhattan building may be replaced by a fifteen- or twenty-story tower on a base. Charles laments that this is not small-scale or incremental, but even his example of good incremental development is similar: in Houston, single-family houses are replaced by low-rise apartment buildings, generating similarly high ratios of the floor areas of redevelopments with the buildings they replaced. Incrementalism in these cases consists of replacing small buildings by much larger ones, gradually, until a few decades later the entire neighborhood is tall.

One way around redevelopment’s need to buy out preexisting buildings is to mandate that future buildings be built to allow adding floors on top of them. Chicago’s Blue Cross Blue Shield Tower is an example. This is a regulation that increases the average cost of construction but reduces the marginal cost and thus the price. It’s also a regulation that only really matters in situations when it is difficult to have a high ratio of new to old floor area, such as in areas that are already high-rise, especially major city CBDs. (It is easy to quintuple floor area ratio when the preexisting buildings have three floors, but not so much when they have twelve.) The current styles of construction of most small buildings, for example sloping roofs common in American and European urban and suburban houses, tend to make adding floors impossible. Of course, the implication that such a regulation should only apply for buildings above a certain height introduces political discretion and hence uncertainty, but at least this is uncertainty that would apply equally to all buildings in an area, which is not always the case for zoning.

What Charles proposes, to develop all vacant lots first and only then start going taller, is then a recipe for high marginal costs, because of the buyout factor. In a small city uniformly developed up to one or two floors, it is difficult to spread the new development across many buildings up to three floors, precisely because there is no way to build single-family houses that are recognizable as such to Americans or Europeans from countries I’ve been to (It’s different in Canada, but this is considered a feature of the low quality of Vancouver’s housing) and that can have floors added to them. In such an environment, building tall is the only way to avoid high housing costs.