Category: Incompetence

Scope Creep is the New Black

In 2009, studies began for a replacement of the Baltimore and Potomac (B&P) Tunnel. This tunnel, located immediately west of Baltimore Penn Station, has sharp curves, limiting passenger trains to about 50 km/h today. The plan was a two-track passenger rail tunnel, called the Great Circle Tunnel since it would sweep a wide circular arc; see yellow line here. It would be about 3 kilometers and cost $750 million, on the high side for a tunnel with no stations, but nothing to get too outraged about. Since then, costs have mounted. In 2014, the plan, still for two tracks, was up to $1 billion to $1.5 billion. Since then, costs have exploded, and the new Final Environmental Impact Statement puts the project at $4 billion. This is worth getting outraged about; at this cost, even at half this cost, the tunnel should not be built. However, unlike in some other cases of high construction costs that I have criticized, here the problem is not high unit costs, but pure scope creep. The new scope should be deleted in order to reduce costs; as I will explain, the required capacity is well within the capability of two tracks.

First, some background, summarized from the original report from 2009, which I can no longer find: Baltimore was a bottleneck of US rail transportation in the mid-19th century. In the Civil War, there was no route through the city; Union troops had to lug supplies across the city, fighting off mobs of Confederate sympathizers. This in turn is because Baltimore’s terrain is quite hilly, with no coastal plain to speak of: the only flat land on which a railroad could be easily built was already developed and urbanized by the time the railroad was invented. It took until the 1870s to build routes across the city, by which time the US already had a transcontinental railroad. Moreover, intense competition between the Pennsylvania Railroad (PRR) and the Baltimore and Ohio (B&O) ensured that each company would built its own tunnel. The two-track B&P is the PRR tunnel; there’s also a single-track freight tunnel, originally built by the B&O, now owned by CSX, into which the B&O later merged.

Because of the duplication of routes and the difficult geography, the tunnels were not built to high standards. The ruling grade on the B&P is higher than freight railroads would like, 1.34% uphill departing the station, the steepest on the Northeast Corridor (NEC) south of Philadelphia. This grade also reduces initial acceleration for passenger trains. The tunnel also has multiple sharp curves, with the curve at the western portal limiting trains today to 30 mph (about 50 km/h). The CSX tunnel, called Howard Street Tunnel, has a grade as well. The B&P maintenance costs are high due to poor construction, but a shutdown for repairs is not possible as it is a key NEC link with no possible reroute.

In 2009, the FRA’s plan was to bypass the B&P Tunnel with a two-track passenger rail tunnel, the Great Circle Tunnel. The tunnel would be a little longer than the B&P, but permit much higher speeds, around 160 km/h, saving Acela trains around 1.5 minutes. Actually the impact would be even higher, since near-terminal speed limits are a worse constraint for trains with higher initial acceleration; for high-performance trains, the saving is about 2-2.5 minutes. No accommodation was made for freight in the original plan: CSX indicated lack of interest in a joint passenger and freight rail tunnel. Besides, the NEC’s loading gauge is incompatible with double-stacked freight; accommodating such trains would require many small infrastructure upgrades, raising bridges, in addition to building a new tunnel.

In contrast, the new plan accommodates freight. Thus, the plan is for four tracks, all built to support double-stacked freight. This is despite the fact that there is no service plan that requires such capacity. Nor can the rest of the NEC support double-stacked freight easily. Of note, Amtrak only plans on using this tunnel under scenarios of what it considers low or intermediate investment into high-speed rail. Under the high-investment scenario, the so-called Alternative 3 of NEC Future, the plan is to build a two-track tunnel under Downtown Baltimore, dedicated to high-speed trains. Thus, the ultimate plan is really for six tracks.

Moreover, as pointed out by Elizabeth Alexis of CARRD, a Californian advocacy group that has criticized California’s own high-speed rail cost overruns, the new tunnel is planned to accommodate diesel trains. This is because since 2009, the commuter rail line connecting Baltimore and Washington on the NEC, called the MARC Penn Line, has deelectrified. The route is entirely electrified, and MARC used to run electric trains on it. However, in the last few years MARC deelectrified. There are conflicting rumors as to why: MARC used the pool of Amtrak electric locomotives, and Amtrak is stopping maintaining them as it is getting new locomotives; Amtrak is overcharging MARC on electricity; MARC wants fleet compatibility with its two other lines, which are unelectrified (although the Penn Line has more ridership than both other lines combined). No matter what, MARC should immediately reverse course and buy new electric trains to use on the Penn Line.

Freight trains are more complicated – all US freight trains are dieselized, even under catenary, because of a combination of unelectrified yards and Amtrak’s overcharging on electric rates. However, if freight through the Great Circle Tunnel is desired, Amtrak should work with Norfolk Southern on setting up an electric district, or else Norfolk Southern should negotiate trackage rights on CSX’s existing tunnel. If more freight capacity is desired, private companies NS and CSX can spend their own money on freight tunnels.

In contrast, a realistic scenario would ignore freight entirely, and put intercity and regional trains in the same two-track tunnel. The maximum capacity of a two-track high-speed rail line is 12 trains per hour. Near Baltimore Penn the line would not be high-speed, so capacity is defined by the limit of a normal line, which is about 24 tph. If there is a service plan under which the MARC Penn Line could get more than 12 tph at the peak, I have not seen it. The plans I have seen call for 4 peak tph and 2 off-peak tph. There is a throwaway line about “transit-like” service on page 17, but it’s not clear what is meant in terms of frequency.

Regardless of what the state of Maryland thinks MARC could support, 12 peak regional tph through Baltimore is not a reasonable assumption in any scenario in which cars remain legal. The tunnels are not planned to have any stations, so the only city station west of Baltimore Penn is West Baltimore. Baltimore is not a very dense city, nor is West Baltimore, most famous for being the location of The Wire, a hot location for transit-oriented development. Most of Baltimore’s suburbs on the Penn Line are very low-density. In any scenario in which high-speed rail actually fills 12 tph, many would be long-range commuters, which means people who live in Baltimore and work in Washington would be commuting on high-speed trains and not on regional trains. About the upper limit of what I can see for the Penn Line in a realistic scenario is 6 tph peak, 3-4 tph off-peak.

Moreover, there is no real need to separate high-speed and regional trains for reasons of speed. High-speed trains take time to accelerate from a stop at Baltimore: by the portal, even high-acceleration sets could not go much faster than 200 km/h. An in-tunnel speed limit in the 160-180 km/h area only slows down high-speed trains by a few seconds. Nor does it lead to any noticeable speed difference with electrified regional trains, which would reduce capacity: modern regional trains like the FLIRT accelerate to 160 km/h as fast as the fastest-accelerating high-speed train, the N700-I, both having an acceleration penalty of about 25 seconds.

The upshot is that there is no need for any of the new scope added since 2009. There is no need for four tracks; two will suffice. There is no need to design for double-stacked freight; the rest of the line only accommodates single-stacked freight, and the NEC has little freight traffic anyway. Under no circumstances should diesel passenger trains be allowed under the catenary, not when the Penn Line is entirely electrified.

The new tunnel has no reason to cost $4 billion. Slashing the number of tunnels from four to two should halve the cost, and reducing the tunnels’ size and ventilation needs should substantially reduce cost as well. With the potential time gained by intercity and regional trains and the reduced maintenance cost, the original budget of $750 million is acceptable, and even slightly higher costs can be justified. However, again because the existing two-track capacity can accommodate any passenger rail volume that can be reasonably expected, the new tunnel is not a must-have. $4 billion is too high a cost, and good transit activists should reject the current plan.

Hyperloop Freight is a Joke

As the ongoing attempt to build a Hyperloop tube in California is crashing due to entirely foreseen technical problems, the company trying to raise capital for the project, Hyperloop One, is looking at other possibilities in order to save face. A few come from other passenger routes: Stockholm-Helsinki is one option, and another is the Dubai-Abu Dhabi, which looks like it may happen thanks to the regime’s indifference to financial prudence. Those plans aren’t any better or worse than the original idea to build it in California. But as part of their refusal to admit failure, the planners are trying to branch into express freight service. Hyperloop freight is especially egregious, in a way that’s interesting not only as a way of pointing out that tech entrepreneurs don’t always know what they’re doing, but also because of its implications for freight service on conventional high-speed rail.

First, let’s go back to my most quoted line on Hyperloop. In 2013 I called it a barf ride, because the plan would subject passengers to high acceleration forces, about 5 m/s^2 (conventional rail tops at 1.5 m/s^2, and a plane takes off at 3-4 m/s^2). This is actually worse for freight than for passengers, which is why the speed limits on curves are lower for freight trains than for passenger trains: as always, see Martin Lindahl’s thesis for relevant European standards. Freight does not barf, but it does shift, potentially dangerously; air freight is packed tightly in small pellets. Existing freight trains are also almost invariably heavier than passenger trains, and the heavier axle loads make high cant deficiency more difficult, as the added weight pounds the outer rail.

Another potential problem is cant. Normally, canting the tracks provides free sideways acceleration: provided the cant can be maintained, no component of the train or tracks feels the extra force. Cant deficiency, in contrast, is always felt by the tracks and the frame of the train; tilting reduces the force felt in the interior of the train, but not on the frame or in the track. At Hyperloop’s proposed speed and curve radius, getting to 5 m/s^2 force felt in the interior of the train, toward the floor, requires extensive canting. Unfortunately, this means the weight vector would point sideways rather than down, which the lightweight elevated tube structure would transmit to concrete pylons, which have high compressible strength but low tensile strength. This restricts any such system to carrying only very lightweight cargo, of mass comparable to that of passengers. This is less relevant to conventional high-speed rail and even maglev, which use more massive elevated structures, but conversely the problem of high forces on the outer rail ensures cant deficiency must be kept low.

Taken together, this means that high-speed freight can’t be of the same type as regular freight. Hyperloop One, to its credit, understands this. The managers are furiously trying to find freight – any kind of freight – that can economically fit. This has to involve materials with a high ratio of value to mass, for example perishable food, jewelry, and mail. SNCF ran dedicated TGV mail trains for 31 years, but decided to discontinue the service last year, in the context of declining mail volumes.

High-speed freight has a last mile problem. Whereas high-speed passenger service benefits from concentration of intercity destinations near the center of the city or a handful of tourist attractions, high-speed freight service has to reach the entire region to be viable. Freight trains today are designed with trucks for last-mile distribution; starting in the 1910s, industry dispersed away from waterfronts and railyards. The combination of trucks and electrification led to a form of factory building that is land-intensive and usually not found in expensive areas. Retail is more centralized than industry, but urban supermarkets remain local, and suburban ones are either local or auto-oriented hypermarkets. Even urban shopping malls as in Singapore are designed around truck delivery. The result is that high-speed freight must always contend with substantial egress time.

Let us now look at access time. How are goods supposed to get from where they’re made to the train station? With passengers, there are cars and connecting transit at the home end. There’s typically less centralization than at the destination end, but in a small origin city like the secondary French and Japanese cities, travel time is not excessive. In a larger city like Osaka it takes longer to get to the train station, but car ownership is lower because of better public transit, which increases intercity rail’s mode share. On freight, the situation is far worse: industry is quite dispersed and unlikely to be anywhere near the tracks, while the train station is typically in a congested location. Conventional rail can build a dedicated freight terminal in a farther out location (for example, auto trains in Paris do not use Gare de Lyon but Bercy); an enclosed system like Hyperloop can’t.

And if industry is difficult to centralize, think of farmed goods. Agriculture is the least centralized of all economic activities; this is on top of the fact that of all kinds of retail, supermarkets are the most local. Extensive truck operations would be needed, just as they are today. And yet, outside analysts are considering perishables as an example of a good where Hyperloop could compete.

With that in mind, any speed benefits coming from high-speed freight services vanish. There are diminishing returns to speed. Since the cost of extra speed does not diminish, there’s always a point where reducing travel time stops being useful, since the effect on door-to-door travel time is too small to justify the extra expense. The higher the total access plus egress time is, the sooner this point is reached, and in freight, the total access and plus egress time is just too long.

In passenger service, the problem of Hyperloop is that it tries to go just a little bit too far beyond conventional high-speed rail. The technical problems are resolvable, at extra cost, and in a few decades, vactrains (probably based on maglev propulsion rather than Elon Musk’s air bearings) may become viable for long-distance passenger rail.

In freight, the situation is very different. Successful freight rail companies, for example the Class I railroads in North America, China Railways, and Russian Railways, make money off of hauling freight over very long distances at low cost. Quite often this is because the freight in question is so heavy that even without substantial fuel taxes, trucks cannot compete on fuel or on labor costs; this is why Western Europe’s highest freight rail mode share is found in Sweden, with its heavy iron ore trains, and in Switzerland, Finland, Austria, with their long-distance freight across the Alps or toward Russia. Increasing speed is not what the industry wants or needs: past US experiments with fast freight did not succeed financially. The fastest, highest-cost mode of freight today, the airplane, has very low mode share, in contrast with the popularity of planes and high-speed trains in passenger service.

None of this requires deep analysis; in response to Hyperloop One’s interest in freight, an expert in logistics asked “why do we need to move cargo at 500 mph?“. The problem is one of face. The entrepreneurs in charge of Hyperloop One cannot admit that they made a mistake, to themselves, to their investors, or to the public. They are bringing the future to the unwashed masses, or so they think, and this requires them to ignore any problem until after it’s been solved, and certainly not to admit failure. Failure is for ordinary people, not for would-be masters of the universe. The announcement of the grand project is always more bombastic and always reaches more people than the news of its demise. It’s on those of us who support good transit and good rail service to make sure the next half-baked idea gets all the skepticism and criticism it deserves.

The Northern Branch Extension is a Waste

As I mentioned in yesterday’s post, negotiations in New Jersey between Governor Chris Christie and the state legislature have resulted in a significant increase in the state fuel tax. The money will raise $16 billion for funding the eight-year Transportation Trust Fund plan, and be matched with federal funds to bring the amount up to $32 billion. Unfortunately, the money is being wasted. Details of most of the plan remain vague, but it appears most of the money will go to road repair; for all I know, $4 billion a year is a reasonable amount for this. But one component of the plan is extension of the Hudson-Bergen Light Rail system north into Bergen County, along the Northern Branch. This is at best a marginal project, and in the long run would make regional rail modernization in Northern New Jersey more difficult.

Despite its name, the HBLR only operates in Hudson County. Plans for extension into Bergen County along the Northern Branch still play an outsized political role due to the name of the line, but have not been realized yet. Right now, the line is partly the light rail system of Jersey City, and partly a circumferential line linking dense areas west of the Hudson, as somewhat of a circumferential. As such, it is a combination of a radial and circumferential. The Northern Branch would send it 13 km farther north into suburbia, terminating in Englewood, a town center with a fraction of the job density of the Jersey City CBD. Projected weekday ridership is 21,000, a little more than 1,500 per km, weak for an urban light rail line. (The HBLR’s existing ridership is 54,000 per weekday on 55 km of route.)

The original cost estimate of the Northern Branch extension was $150 million, low for the length of the line. While reactivating a closed commuter rail like the Northern Branch should be cheaper, the line is single-track still hosts some freight service, so light rail would have to build new tracks in the same right-of-way, raising the cost range to that of urban light rail. Unfortunately, the cost rapidly escalated: by 2009 it was up to $800-900 million, and in 2015, after the proposal was shortened to its current length from an 18 km proposal going deeper into the Bergen County suburbs, the cost was up to $1 billion. The cost per rider is still much better than that of the Gateway Tunnel, but it makes the project marginal at best.

While the high cost may be surprising, at least to the reader who is unused to the expense of building in or near New York, the limited ridership is not. The original plan, going beyond Englewood, would have terminated the line in Tenafly, a wealthy suburb where my advisor at Columbia used to live. Many people in Tenafly objected to that plan, not so much on the usual NIMBY grounds of traffic and noise as on the grounds that the line would not be of much use to them. They were interested in taking public transit to go to Manhattan, and the HBLR system would not be of any use. Of course, Columbia professors would not be using a rail network that went directly to Midtown or Lower Manhattan, but most of the suburb’s Manhattan-bound residents work in the CBD and not at Columbia.

I would probably not be this adamantly against the Northern Branch project if it were just one more over-budget light rail line at $45,000 per projected rider. The US has no shortage of these. Rather, it’s the long-term effect on regional rail.

The Northern Branch would make a good commuter rail line, going from Pavonia (or possibly Hoboken) north to Nyack, connecting to the HBLR at its present-day northern terminus, with about the same stop spacing as the proposed HBLR extension. Potentially it could even get a loop similar to the proposed Secaucus loop of the Gateway project allowing it to enter Penn Station directly. An even better connection would involve a second tunnel between Pavonia, Lower Manhattan, and Atlantic Terminal on the LIRR, with a new transfer station at the junction of the Northern Branch and the Northeast Corridor. Consult this map, depicting the inner segments of various potential commuter lines: the Northern Branch is the easternmost yellow line, the Northeast Corridor is in red and green.

The importance of the Northern Branch for regional rail is threefold. First, the easternmost line in North Jersey today, the Pascack Valley Line, misses a large swath of territory farther east, which is covered by the Northern Branch and by the West Shore Line. The West Shore Line actually passes through somewhat denser suburbs, with more Manhattan-bound commuters, but is a major freight route, whereas the Northern Branch has little freight traffic, which can be scheduled around passenger trains or even kicked out. Second, again shared with the West Shore Line, the Northern Branch provides a north-south line in Hudson County west of Bergen Hill, where there is suitable land for transit-oriented development. And third, the terminus, Nyack, is a town center with a walkable core.

I wouldn’t really object to making the Northern Branch light rail if it were cheap. At the original cost estimate of $150 million, I would be mildly annoyed by the lack of long-term thinking, but I’d also recognize that the cost per rider was low, and at worst the state would have to redo a $150 million project. At $1 billion, the calculus changes considerably; it’s a significant fraction of what a tunnel under the Hudson should cost (though not what it does cost given the extreme amount of scope creep).

High costs, as I said in 2011, should not be an excuse to downgrade transit projects to a cheaper, less useful category (such as from a subway to light rail). In this case we see the opposite happen: high costs are a reason to reject a downgraded project, since the cost per rider is no longer low enough to justify shrugging off the long-term effect on regional rail restoration.

Train Weight and Safety

A recent New Jersey Transit train accident, in which one person was killed and more than a hundred was injured, has gotten people thinking about US rail safety again. New Jersey has the second lowest fuel tax in the US, and to avoid raising it, Governor Chris Christie cut the New Jersey Transit budget (see PDF-pp. 4-5 here); perhaps in reaction to the accident, Christie is announcing a long-in-the-making deal that would raise the state’s fuel tax. But while the political system has been discussing funding levels, transit advocates have been talking about regulations. The National Transportation Safety Board is investigating whether positive train control could have prevented the accident, which was caused by overspeed. And on Twitter, people are asking whether Federal Railroad Administration regulations helped protect the train from greater damage, or instead made the problem worse. It’s the last question that I want to address in this post.

FRA regulations mandate that US passenger trains be able to withstand considerable force without deformation, much more so than regulations outside North America. This has made American (and Canadian) passenger trains heavier than their counterparts in the rest of the world. This was a major topic of discussion on this blog in 2011-2: see posts here and here for an explanation of FRA regulations, and tables of comparative train weights here and here. As I discussed back then, FRA regulations do not prevent crumpling of passenger-occupied space better than European (UIC) regulations do in a collision between two trains, except at a narrow range of relative speeds, about 20-25 mph (30-40 km/h); see PDF-pp. 60-63 of a study by Caltrain, as part of its successful application for waivers from the most constraining FRA regulations. To the extent people think FRA regulations have any safety benefits, it is purely a stereotype that regulations are good, and that heavier vehicles are safer in crashes.

All of this is old discussions. I bring this up to talk about the issue of systemwide safety. Jacob Anbinder, accepting the wrong premise that FRA regulations have real safety benefits, suggested on Twitter that rail activists should perhaps accept lower levels of rail safety in order to encourage mode shift from much more dangerous cars toward transit. This is emphatically not what I mean: as I said on Twitter, the same policies and practices that lead to good train safety also lead to other good outcomes, such as punctuality. They may seem like a tradeoff locally within each country or region, but globally the correlation goes the other way.

In 2011, I compiled comparative rail safety statistics for the US (1 dead per 3.4 billion passenger-km), India (1 per 6.6 billion), China (1 per 55 billion), Japan (1 per 51 billion), South Korea (1 per 6.7 billion), and the EU (1 per 13 billion), based on Wikipedia’s lists of train accidents. The number for India is an underestimate, based on general reports of Mumbai rail passenger deaths, and I thought the same was true of China. Certainly after the Wenzhou accident, the rail activists in the developed world that I had been talking to stereotyped China as dangerous, opaque, uninterested in passengers’ welfare. Since then, China has had a multi-year track record without such accidents, at least not on its high-speed rail network. Through the end of 2015, China had 4.3 billion high-speed rail passengers, and by 2015 its ridership grew to be larger than the rest of the world combined. I do not have statistics for high-speed passenger-km, but overall, the average rail trip in China, where there’s almost no commuter rail, is about 500 km long. If this is also true of its high-speed rail network, then it’s had 2.15 trillion high-speed passenger-km, and 1 fatality per 54 billion. This is worse than the Shinkansen and TGV average of zero fatalities, but much better than the German average, which is weighed down by Eschede. (While people stereotype China as shoddy, nobody so stereotypes Germany despite the maintenance problems that led to the Eschede accident.)

I bring up China’s positive record for two reasons. First, because it is an example of how reality does not conform to popular stereotypes. Both within China and in the developed world, people believe China makes defective products, cheap in every sense of the term, and compromises safety; the reality is that, while that is true of China’s general environmental policy, it is not true of its rail network. And second, China does not have buff strength requirements for trains at all; like Japan, it focuses on collision avoidance, rather than on survivability.

The importance of the approaches used in Japan and on China’s high-speed rail network is that it provides safety on a systemwide level. By this I do not mean that it encourages a mode shift away from cars, where fatality rates are measured in 1 per hundreds of millions of passenger-km and not per tens of billions. Rather, I mean that the entire rail network is easier to run safely when the trains are lighter.

It is difficult to find exact formulas for the dependence of maintenance costs on train weight. A discussion on Skyscraper City, sourced to Bombardier, claims track wear grows as the cube of axle load. One experiment on the subject, at low speeds and low-to-moderate axle loads, finds a linear relationship in both axle load and speed. A larger study finds a relationship with exponents of 3-5 in both dynamic axle load and speed. The upshot is that at equal maintenance cost, lighter trains can be run faster, or, at equal speed, lighter trains make it easier to maintain the tracks.

The other issue is reliability. As I explained on Twitter, the same policies that promote greater safety also make the system more reliable, with fewer equipment failures, derailments, and slowdowns. On the LIRR, the heavy diesel locomotives have a mean distance between failures of 20,000-30,000 km, and the medium-weight EMUs 450,000 (see PDF-pp. 21-22 here). The EMUs that run on the LIRR (and on Metro-North), while heavier than they should be because of FRA requirements, are nonetheless pretty good rolling stock. But in Tokyo, one rolling stock manufacturer claims a mean distance between failures of 1.5 million km. While within Japan, the media responds to fatal accidents by questioning whether the railroads prioritize the timetable over safety, the reality is that the overarching focus on reliability that leads to low maintenance costs and high punctuality also provides safety.

In the US, especially outside the EMUs on the LIRR and Metro-North, the situation is the exact opposite. The mean distance between failures for the LIRR’s diesel locomotives is not unusually low: on the MBTA, the average is about 5,000 km, and even on the newest locomotives it’s only about 20,000 (State of the Commuter Rail System, PDF-pp. 8-9). The MBTA commuter rail system interacts with freight trains that hit high platforms if the boxcars’ doors are left open, which can happen if vandals or train hoppers open the doors; as far as I can tell, the oversize freight on the MBTA that prevents easy installation of high platforms systemwide is not actually oversize, but instead veers from the usual loading gauge due to such sloppiness.

Of course, given a fixed state of the infrastructure and the rolling stock, spending more money leads to more safety. This is why Christie’s budget cuts are important to publicize. Within each system, there are real tradeoffs between cost control and safety; to Christie, keeping taxes low is more important than smooth rail operations, and insofar as it is possible to attribute political blame for such low-probability events as fatal train accidents, Christie’s policies may be a contributing factor. My contention here is different: when choosing a regulatory regime and an overarching set of operating practices, any choice that centers high performance and high reliability at the expense of tradition will necessarily be safer. The US rail community has a collective choice between keeping doing what it’s doing and getting the same result, and transitioning operating practices to be closer to the positive results obtained in Japan; on safety, there is no tradeoff.

When Through-Running Is Inappropriate

I support through-running of regional trains: as far as possible, trains should not terminate in major city centers, but instead run through to urban neighborhoods and suburbs on the other side of the CBD. My first blog posts made this point about New York, and over the years I’ve written about this in the contexts of New York, Boston, Washington, Chicago, and Tel Aviv. However, in secondary cities, through-running is not always appropriate policy. If a city is near the edge and not at the center of its metro area, then quite often it’s preferable to run a separate service, which may overlap the primary city’s regional rail system. In some cases, through-running is actively harmful; unfortunately, this is currently done in San Jose and Providence.

Theory

Consider the following example city:

throughrunexample

The metro area lies on an east-west rail line, and consists of a central city several suburbs; higher-density areas are denoted by darker shades, with the primary CBD in the darkest shade. The city proper also has five secondary CBDs, two of which are on the rail line. On the west, one suburb, really a secondary city, is larger than the rest, and has its own CBD, as job-dense as one of the primary city’s secondary CBDs. With rough symmetry of suburban demand west and east, there is no good reason why trains should not through the primary CBD, and good reasons why they should:

  • People in the eastern suburbs may work in the secondary CBD just west of the primary one, and people in the western suburbs may work in the secondary CBD just east of the primary one.
  • The primary CBD may not have room to park trains at rush hour without a costly railyard expansion.
  • People within the central city may use the line as a rapid transit trunk, to get to either the primary CBD or the two secondary CBDs on the line, as well as to residential neighborhoods not depicted in the diagram.

This is relatively uncontroversial – urban transit is designed along the same guidelines. Also uncontroversial is the question of how far east the commuter line should run: the diagram shows a string of medium-size suburbs, so the line should run as far as the easternmost one, potentially with short-turn runs if the trains at the end are too empty.

The real controversy is how far west to run the service. On the one hand, the secondary city provides a natural outer anchor, with some reverse-peak ridership potential, so there’s an argument for terminating service there. I have criticized the Human Transit model of anchoring as a matter of urban planning, but as a matter of transit planning with fixed urban layout, it is sound; see explanations here and here. On the other hand, there are two smaller suburbs farther west, where people might want to commute to either the primary city or the secondary one, so perhaps service should run farther, with many trains short-turning at the secondary city to avoid running too many empty trains at the western end.

Which of the two options is better – terminating services at the secondary city or continuing onward – depends on the frequency the trunk rail line can support. The reason is that continuing onward requires a very large drop in capacity to avoid empty trains. In the depicted diagram, in relative units, 10% of the western suburbs’ built-up residential area is west of the secondary city; maybe another 10% is the western areas of the secondary city, which could host a station in addition to that at the city’s center. This means that nearly all trains should short-turn; only perhaps one in three or four should continue. If the demand is so intense that a quarter of the base frequency is enough, then trains should continue. But most likely, it isn’t. An individual commuter line with a train every 10 minutes off-peak would be stepped down to every half an hour at the western end, which is borderline; a train every 10 minutes off-peak almost never happens outside Paris, Tokyo, and other enormous systems, except when multiple branches interline to a single trunk.

The alternative is to terminate commuter trains at the secondary city, but then run supplemental service, centered at the secondary city. This supplemental service is not supposed to serve demand into the primary city, handling supercommuters from the western end via a timed transfer (with possible peak through-service), so it can run shorter trains at higher frequency. Sometimes, the secondary city’s CBD must be judged too auto-oriented to be served with commuter rail, and then the correct service pattern is no trains at all west of the secondary city.

Examples

In both Providence and San Jose, a situation akin to the above diagram occurs, except without any through-service beyond the primary CBD (respectively, Boston and San Francisco). Of course, San Jose has more residents than San Francisco, 1.03 million compared with 870,000, but it has only 360,000 jobs to San Francisco’s 610,000. Moreover, San Jose’s employment is more dispersed; according to OnTheMap, its CBD’s job density is about comparable to that of Providence’s CBD. Evidently, Caltrain ridership is 13,600 per weekday at San Francisco and 4,200 at San Jose Diridon (PDF-p. 6 here), with both stations located somewhat away from their respective cities’ CBDs. A proper comparison of Providence to Boston is harder to make, since South Station has multiple line and not just the Providence Line, but Providence’s secondary role within New England is well-understood.

In both cities, service runs beyond the secondary city, at reduced frequency. Between San Francisco and San Jose, Caltrain runs 5 trains per hour at the peak, and a train every hour off-peak; but Caltrain also runs three trains per day in each direction south to Gilroy, 47 km to the south (San Francisco-San Jose is 77 km). Between Boston and Providence, a distance of 70 km, the MBTA runs 3-4 trains per hour at the peak and a train every 1.5-2 hours off-peak, but one train per hour at the peak and one train every four hours off-peak continues another 31 km south to Wickford Junction.

Both tails, to Gilroy and to Wickford Junction, are significant drags on the ability of their respective cores to modernize. Ridership is very low: Tamien, just south of San Jose Diridon, has 1,100 weekday riders, but the sum total of all the stations to its south is 559; the two stations south of Providence have between them 454 weekday riders, compared with about 2,300 at Providence and 20,000 on the Providence Line overall (see PDF-pp. 74 and 77 of the 2014 MBTA Bluebook). In both cases, low ridership is a cause of poor service rather than a consequence: Clem Tillier tallied the population and job densities near each Caltrain station and found that, except in the southern neighborhoods of San Jose, there is no real ridership potential on the Gilroy extension; a similar analysis of the Providence Line’s tail has not been carried out, but one of its two stations is in a low-density suburb without many Boston-bound commuters, while Wickford Junction is surrounded by undeveloped land. Caltrain is currently planning to electrify south to Tamien, but there is no justification for continuing electrification further, which means that maintaining Gilroy service would require mixing diesel locomotive-hauled trains with lightweight EMUs; moreover, south of Tamien, the tracks are owned by Union Pacific rather than by Caltrain, and UP has little interest in allowing modern passenger trains on its tracks. In Rhode Island, an additional complication is that the line from Providence down to Wickford Junction is prime high-speed rail territory, and commuter rail ridership is frankly too low to justify complex scheduling with multiple overtakes, unlike the situation farther north in Massachusetts.

In the Bay Area, there is little that can be done, due to the low potential ridership south of Tamien, San Jose’s suburban layout and the distance of Diridon from the CBD, and UP ownership of the tracks. Perhaps a few diesel trains could run to San Jose Diridon with timed transfers to the electrified line from Tamien to San Francisco, but quite likely service could just be canceled. In Rhode Island, Wickford Junction should probably be closed due to low ridership, but Peter Brassard proposed an alternative, a Providence-focused line running short trains at medium frequency (perhaps once every 15 minutes), with very short interstations in order to serve Providence neighborhoods and not just the CBD. Such a line, running at the same average speed as a freight train due to the frequent stops, would interfere heavily with intercity trains, which means that four-tracking the line is a necessary precondition, as discussed here, but this may be worth it given potential local ridership. The most constrained part of the right-of-way is alongside the Route 10 expressway, which requires considerable repairs and is currently being overhauled at high cost.

Amtrak’s Rolling Stock Order: Followup

A year ago, based on a leak from Senator Charles Schumer’s office, I attacked Amtrak for paying double for its new high-speed trains – $2.5 billion for 28 trainsets, about $11 million per car. Amtrak at the time denied the press release, saying it was still in the process of selecting a bidder. However, last week Amtrak announced the new order, confirming Schumer’s leak. The trainsets are to cost $2 billion, or $9 million per car, with an additional $500 million spent on other infrastructure. The vendor is Alstom, which is branding all of its export products under the umbrella name Avelia; this train is the Avelia Liberty.

You can see a short promotional video for the trains here and read Alstom’s press release here. Together, they make it obvious why the cost is so high – about twice as high per car as that of Eurostar’s Velaro order, and three times as high as that of the shorter-lived N700 Shinkansen. The Avelia Liberty is a bespoke train, combining features that have not been seen before. Technical specs can also be seen in Alstom’s press kit. The Avelia Liberty will,

  • Have a top speed of 300 km/h.
  • Have articulated bogies.
  • Be capable of 7 degrees of tilt, using the same system as in Alstom’s Pendolino trainset.

In particular, the combination of high speed and high degree of tilt, while technically feasible, does not exist in any production train today. It existed in prototype form, as a tilting TGV, but never made it to mass production. The Pendolino has a top speed of 250 km/h, and the ICE-T has a top speed of 240 km/h. Faster tilting trains do not tilt as much: Talgo claims the Talgo 350 is capable of lateral acceleration of 1.2 m/s^2 in the plane of the train, which corresponds to 180 mm of cant deficiency, achievable with 2-3 degrees of tilt; the tilting Shinkansen have moderate tilting as well, which the JRs call active suspension: the N700 tilts 1 degree, and appears capable of 137 mm of cant deficiency (270 km/h on 2.5 km curves with 200 mm cant), whereas the E5 and E6 tilt 2 degrees, and appear capable of 175 mm (in tests they were supposed to do 360 km/h on 4 km curves with 200 mm cant, but only run at 320 km/h for reasons unrelated to track geometry).

I have argued before, primarily in comments, that a train capable of both high speed and high degree of tilt would be useful on the Northeast Corridor, but not at any price. Moreover, the train is not even planned to run at its advertised top speed, but stay limited to 257 km/h (160 mph), which will only be achievable on short segments in Massachusetts, Rhode Island, and New Jersey. Amtrak has no funded plan to raise the top speed further: the plans for constant-tension catenary in New Jersey are the only funded item increasing top speed. There is no near-term plan on the horizon to obtain such funding – on the contrary, Amtrak’s main priority right now is the Gateway tunnel, providing extra capacity and perhaps avoiding a station throat slowdown, but not raising top speed.

Running trains at 300 km/h on the segments that allow the highest speeds today, or are planned to after the speedup in New Jersey, would save very little time (75 seconds in New Jersey, minus acceleration and deceleration penalties). Making full use of high top speed requires sustaining it over long distances, which means fixing curves in New Jersey that are not on the agenda, installing constant-tension catenary on the entire New York-Washington segment and not just over 40 km of track in New Jersey to eliminate the present-day 215 km/h limit, and building a bypass of the entire segment in southeastern Connecticut along I-95. None of these is on the immediate agenda, and only constant-tension catenary is on the medium-term agenda. Hoping for future funding to materialize is not a valid strategy: the trains would be well past the midpoint of their service lives, and spend many years depreciating before their top speed could be used.

What’s more, if substantial bypasses are built, the value of tilting decreases. In advance of the opening of the Gotthard Base Tunnel, Swiss Federal Railways (SBB) ordered 29 trainsets, without tilting, replacing the tilting Pendolino trains that go through the older tunnel. SBB said tilting would only offer minimal time reduction. The eventual cost of this order: about $36 million per trainset as long as 8 US cars. On the entire Northeast Corridor, the place where tilting does the most to reduce travel time is in Connecticut, and if the eastern half of the tracks in the state are bypassed on I-95, tilting loses value. West of New Haven, tilting is not permitted at all, because of Metro-North’s rules for trains using its tracks; on that segment, tilting will always be valuable, because of the difficulty of finding good rights-of-way for bypasses not involving long tunnels, but to my knowledge Amtrak has not made any move to lift the restriction on tilting. Even with the restriction lifted, a 300+ km/h train with moderate tilting, like the N700 or E5/6 or the Talgo AVRIL, could achieve very fast trip times, with only a few minutes of difference from a hypothetical train with the same top speed and power-to-weight ratio and 7 degrees of tilt. It may still be worth it to develop a train with both high speed and a high degree of tilt, but again, not at any cost, and certainly not as the first trainset to use the line.

Another issue is reliability. The Pendolino tilt system is high-maintenance and unreliable, and this especially affects the heavier Acela. SBB’s rejection of tilting trains was probably in part due to the reliability issues of previous Pendolino service across the Alps, leading to long delays. Poor reliability requires more schedule padding to compensate, and this reduces the advantage gained from faster speed on curves. While tilting trains are overall a net positive on curvy routes like the Connecticut segment of the Northeast Corridor, they are probably not useful in any situation in which 300 km/h top speeds are achievable for a meaningful length of time. This goes double for the Avelia Liberty, which is not a proven Pendolino but a new trainset, sold in a captive market that cannot easily replace it if there are maintenance issues.

In my post a year ago, I complained that Amtrak’s specs were conservative, and did not justify the high cost. I stand behind that assessment: the required trip times are only moderate improvements over the current schedule. At least between New York and Boston, the improvement (9 minutes plus stop penalty at New London) is less than the extent of end-of-line schedule padding, which is at least 10 minutes from Providence to Boston for northbound trains. However, to achieve these small trip time improvements, Amtrak elected to demand exacting specs from the trainsets, leading to high equipment costs.

In 2013, I expounded on this very decision by borrowing a Swiss term: the triangle of rolling stock, infrastructure, and timetable. Planning for all three should be integrated. For example, plans for increases in capacity through infrastructure improvements should be integrated with plans for running more trains, with publicly circulated sample schedules. In this case, the integration involves rolling stock and infrastructure: at low infrastructure investment, as is the case today, there is no need for 300 km/h trainsets, whereas at high investment, high top speed is required but 7-degree tilt is of limited benefit. Instead of planning appropriately based on its expectations of near-term funding, Amtrak chose to waste about a billion dollars paying double for trainsets to replace the Acela.

Northeast Corridor, 95% Cheaper: Frankford Junction

Amtrak’s plan for high-speed rail on the Northeast Corridor, at a cost of about $290 billion depending on the exact alternative chosen, is unacceptably costly. I went into some details of where excess cost comes from in an older post. In this post, I hope to start a series in which I focus on a specific part of the Northeast Corridor and propose a cheaper alternative than what the NEC Future plan assumes is necessary. The title is taken from a post of mine from four years ago; since then, the projected costs have doubled, hence the title is changed from 90% cheaper to 95% cheaper. In this post, I am going to focus on untangling Frankford Junction.

Frankford Junction is one of the slowest parts of the Northeast Corridor today south of New York. It has a sharp S-curve, imposing a speed limit of 50 mph, or 80 km/h. While worse slowdowns exist, they are all very close to station throats. For example, Zoo Junction just north of Philadelphia 30th Street Station has a curve with radius about 400 meters and an interlocking, so that superelevation is low. The speed limit is low (30 mph, or 50 km/h), but it’s only about 2 km out of the station; it costs about 2 minutes, and with proper superelevation and tilting the speed limit could be doubled, reducing the time cost to 25 seconds. In contrast, Frankford Junction is about 13 km out of 30th Street Station; an 80 km/h restriction there, in the middle of what could be a 200 km/h zone, makes it uneconomic for trains to accelerate to high speed before they clear the junction. This impacts about 4 km, making it a 108-second slowdown, which can be mitigated by either more tilting or a wider curve. In reality, a mixture is required.

The NEC Future plan for high-speed rail, the $290 billion Alternative 3, avoids the Frankford Junction S-curve entirely by tunneling under Center City and building a new HSR station near Market East, a more central location than 30th Street; see PDF-pp. 19, 20, and 78 of Appendix A of the environmental impact statement. This option should be instantly disposed of: 30th Street is close enough to the Philadelphia CBD, and well-connected enough to the region by public transit, that it is no worse a station choice than Shin-Osaka. The Tokaido Shinkansen could not serve Osaka Station as a through-station without tunneling; since Japan National Railways wanted to be able to extend HSR onward, as it eventually did with the Sanyo Shinkansen, it chose to serve Osaka via a new station, Shin-Osaka, 3 km away from the main station. Given the expense of long tunnels under Philadelphia, the slightly less optimal station today should be retained as good enough.

A lower-powered plan providing some HSR functionality, Alternative 2, does not include a new tunnel under Philadelphia, but instead bypasses Frankford Junction. On Appendix A, this is on PDF-pp. 19, 20, and 70. Unfortunately, the bypass is in a tunnel, which appears to be about 4 kilometers. The tunnel has to cross under a minor stream, Frankford Creek, adding to the cost. Instead, I am going to propose an alignment that bypasses the tunnel, with moderate takings, entirely above ground.

In brief, to minimize trip times without excessive construction, it is best to use the highest superelevation and cant deficiency that HSR technology supports today. The maximum superelevation is 200 mm, on the Tokaido Shinkansen (link, PDF-p. 41); there were plans to raise superelevation to 200 mm on the Tohoku Shinkansen, to permit a maximum speed of 360 km/h, but they were shelved as that speed created problems unrelated to superelevation, including noise, pantograph wear, and long braking distances. The maximum cant deficiency on existing trainsets capable of more than 300 km/h is about 180 mm, including the E5/E6 Shinkansen and the Talgo 350 and Talgo AVRIL. Tilting trains capable of nearly 300 mm cant deficiency exist, but are limited to 250 km/h so far. With 200 mm superelevation and 175 mm cant deficiency, speed in meters per second equals square root of (2.5 * curve radius in meters); the minimum curve radius for 200 km/h is then 1,235 meters.

An S-curve requires some distance to reverse the curve, to avoid shocking the train and the passengers with a large jerk, in which they suddenly change from being flung to the right to being flung to the left. If you have ridden a subway, sitting while the train was decelerating, you must have noticed that as the train decelerated, you felt some force pushing you forward, but once the train came to a complete stop, you’d be pulled backward. This is the jerk: your muscles adjusted to being pushed forward and resisting by pulling backward, and once the train stopped, they’d pull you back while adjusting back to the lack of motion. This is why S-curves built a long time ago, before this was well-understood, impose low speed limits.

With today’s computer-assisted design and engineering, it’s possible to design perfect S-curves with constant, low jerk. The limits are described in the above link on PDF-pp. 30 and 38. With the above-described specs, both sets of standards described in the link require 160 meters of ramp. For a single transition from tangent track to a fully superelevated curve, this can be modeled very accurately as 80 meters of straight track plus the circular curve (half the transition spiral is within the curve); the displacement from an actual spiral curve is small. For an S-curve, this requires double the usual transition, so 160 meters of tangent track between the two circles; bear in mind that this distance grows linearly with speed, so on full-speed 360 km/h track, nearly 300 meters are required.

Here is a drawing of two circles and a tangent track between them. The curve of course consists only of a short arc of each circle. The straight segment is a little less than 700 meters, which permits a gentle spiral. The curves have radius 1,250 meters. Takings include a charter school, a wholesale retailer, an auto shop, and what appears to be industrial parking lots, but as far as I can tell no residences (and if I’m wrong, then very few residences, all very close to industrial sites). The charter school, First Philadelphia Preparatory, is expanding, from 900 students in 2012-3 to an expected 1,800 in 2018-9. School construction costs in Pennsylvania are high, and $100 million is expected for a school of that size; see also table 5 on PDF-p. 7 here for national figures. The remaining takings are likely to cost a fraction of this one. Even with the high cost of takings, it is better to realign about 2 kilometers of track above-ground, at perhaps $150 million, than to build 4 km of tunnel, at $1.5 billion; both figures are based on cost items within the NEC Future . This represents a saving of about 83% over Alternative 2, which is projected to cost $116-121 billion excluding rolling stock (PDF-p. 42 of chapter 9 of the EIS).

Given the long spiral length, it may be feasible to avoid the charter school entirely. This would probably require shrinking curve radius slightly, permitting 180 or 190 km/h rather than 200 km/h. However, the travel time cost is measured in seconds: with about 11 km from the end of Zoo Junction to the northern end of Frankford Junction, of which 1 is required just to accelerate to speed, the difference between 200 and 180 km/h is 20 seconds. Further savings, reducing this time difference, are possible if the speed limit without taking the school is 190, or if trains accelerate to 200, decelerate to curve speed, and accelerate again to the north. This option would improve the cost saving over Alternative 2 to about 90%.

The correct way forward for affordable improvement of the Northeast Corridor is to look for ways in which expensive infrastructure can be avoided. If a tunnel can be replaced by a viaduct at the cost of a few extra takings, it should be. If an expensive undertaking can be avoided at the cost of perhaps 10 seconds of extra travel time, then it probably should be avoided. There should be some idea of how much it’s acceptable to spend per minute of marginal travel time saving, by segment: the New York-Philadelphia segment has the heaviest traffic and thus should have the highest maximum cost per unit of time saved. But even then, $100 million for 20 seconds is probably too high, and $100 million for 10 seconds is certainly too high.

Select Bus Service Problems

I recently visited New York. I stayed in Kew Gardens Hills, a neighborhood located between Jamaica and Flushing, just close enough to the subway that it’s plausible to walk but just far enough that this walk is uncomfortable and I preferred to take a bus. The bus route, Main Street, is one of Queens’ busiest (see data here and here). I’ve been calling for investment in it for years, going back to a fantasy spite map I drew so long ago I don’t remember what year it was, and continuing more recently in my post on where New York should and shouldn’t build light rail. Last year, the route did get Select Bus Service, and I took it a few times. The result is not good.

Main Street maintains two bus corridors: the local Q20, and the Select Bus Service Q44. Almost every SBS route is an overlay of a local route and a rapid route; on the local route passengers must board from the front and pay within view of the driver, and on the rapid route passengers must validate a ticket at ticketing machines beforehand and can then board the bus from any stop, with the fare enforced via random checks for ticket receipts. This leads to the following problems, some preventable, some inherent to this setup:

  1. Passengers who can take either the local or the SBS route need to decide in advance whether to validate their tickets at the machines or not, based on whether the next bus is SBS. The resulting last-minute validation delays boarding. After the mayhem caused by the introduction of SBS to the M15, on First and Second Avenues, bus drivers on local routes began to accept the receipts spitted out by the SBS ticketing machines. However, this practice is either inconsistent or not widely-known among occasional bus riders, such as the people I was staying with, who own cars.
  2. The combination of local and limited buses on a medium-frequency route such as Main Street makes it impossible to maintain even headways. Even within each route (Q20 or Q44) I repeatedly saw bunching, but the different speeds of the Q20 and Q44 make bunching between a local and an express inevitable at some point on the route. Off-peak weekday frequency is 10 minutes on the Q20 and 8 on the Q44, which isn’t good enough to justify this split, especially given the bunching within each route; some stations will always be scheduled to have 8-minute service gaps, and in practice could see 15-minute gaps because of the bunching. See more on this problem of locals and rapids on infrequent routes on Human Transit.
  3. The expense of the ticketing machines ($75,000 per stop for a pair of modified MetroCard vending machines and a machine that takes coins) limits how widely they can be installed. Everywhere else where proof-of-payment is used, holders of valid transfers and season passes can just board the train or bus and show their pass to an inspector. This would be especially useful in New York, because the biggest crunch at SBS stops occurs when many passengers arrive at the stop at once, which in turn is the most common where passengers transfer from the subway. The slow process of validating a ticket leads to queues at busy times, and adding more machines is difficult because of their cost.
  4. Stop spacing is never what it should be. Most developed countries have converged on a standard of about 400-500 meters between successive bus stops. North America instead has converged on 200 meters, leading to slow buses that stop too often; see an old Human Transit post on the subject here. The stop spacing on the segment of the Q44 I was using was two stops in 1.7 km, leading to long walks between stops.
  5. On the schedule, the Q44 makes 15 stops in 9.2 km between its origin in Jamaica and Flushing, and takes 42 minutes in the midday off-peak. This is an average speed of 13.1 km/h. In contrast, Vancouver’s limited-stop buses, which average about a stop per kilometer on Broadway and 4th Avenue, average 20 km/h and 30 km/h respectively; the 4th Avenue buses do not have off-board fare collection, but there’s less traffic than on Broadway, and the stoplights give priority to through-traffic, both private and public, over crossing traffic.

The basic problem with New York’s approach to Select Bus Service is that all North American bus rapid transit ultimately descends from Jaime Lerner’s sales pitch of BRT as a cheap subway on tires, at grade. Lerner implemented BRT in Curitiba successfully, in the context of low wages: construction costs appear to only weakly depend on wealth (see e.g. my posts here, here, here, here, and here), but bus driver costs rise with average income, making replacing fifteen bus drivers with one subway driver a crucial money saver in rich cities and an unaffordable luxury in poor ones. North American BRT imitates Latin American BRT’s role as a cheap subway substitute, and ignores the superior usage of bus services in Europe, with which American transit planners do not dialog; there’s no systematic dialog with Latin American planners either, but Lerner has aggressively pitched his ideas to receptive audiences, whereas no comparable figure has pitched European-style reforms to the US.

In cities that think of BRT as a subway substitute, the BRT network will tend to be small, consisting of a few lines only serving the most important corridors, and bundle various features of improved transit together (off-board fare collection, larger vehicles, bus lanes, signal priority). After all, a line can’t be partly a subway and partly a bus. In Bogota, whose BRT system has eclipsed Curitiba and is the world’s largest, the BRT lines run different vehicles from the local lines: local buses have doors opening on the right to the curb, BRT buses have doors opening on the left to a street median bus station, some hybrids have buses with doors on both sides (see photos on Spanish Wikipedia). ITDP, which promotes Latin American-style BRT around the world, has a BRT scoring guideline that awards points to systems that brand their BRT lines separately from the rest of the bus network, as New York does with SBS.

In the European thinking, there’s already an improved quality urban transit service: the subway, or occasionally the tram. The bus is a bus. The biggest difference is that subway networks are smaller than bus networks. Paris and London, both with vast urban rail networks, have a number of subway lines measured in the teens, plus a handful of through-running commuter services; they have hundreds of bus routes. Instead of branding a few buses as special, they invest in the entire bus network, leading to systemwide proof-of-payment in many cities. Bus lanes and signal priority are installed based on demand on an individual segment basis. New York installs bus lanes without regard to local versus SBS status, but retains the special SBS brand, distinguished by off-board fare collection, and only installs it on a per-route basis rather than systemwide.

The other issue, unique to New York, is the ticket receipts. Everywhere else that I know of, bus stops do not have large ticket machines as New York does. Vancouver, which otherwise suffers from the same problem of having just a few special routes (called B-Lines), has no ticket machines at B-Line stops at all: people who have valid transfers or  monthly passes can board at their leisure from any door, while people who don’t pay at the front as on local buses. SBS in contrast does not give passengers the option of paying at the front. In New York, people justify the current system by complaining that the MetroCard is outdated and will be replaced by a smart card any decade now; in reality, systems based on paper tickets (including Vancouver, but also the entire German-speaking world) manage to have proof-of-payment inspections without smartcards. Small devices that can read the MetroCard magnetic stripe are ubiquitous at subway stops, where people can swipe to see how much money they have left.

The right path for New York is to announce that every bus route will have off-board fare collection, regardless of stop spacing. It should also engage in stop consolidation to reduce the interstation to about 400-500 meters, but this is a separate issue from fare collection. Similarly, the question of bus lanes should be entirely divorced from fare collection. There should be no ticketing machines at bus stops of the kind currently used. At most, stops should have validators, similar to the MetroCard readers at subway turnstiles but without the fare barrier. Validators are not expensive: smartcard readers in Singapore are consumer items, available to people for recharging their cards at home via their credit cards for about $40, a far cry from the $75,000 cost in New York today. People with valid transfers or unlimited cards should be able to board without any action, and people without should be able to pay on the bus.

Finally, the split between local and rapid routes should be restricted to the busiest routes, with the highest frequency in the off-peak. Conceivably it should be avoided entirely, in favor of stop consolidation, in order to increase effective frequency and reduce bunching. The city’s single busiest route, the M15, has 7-minute SBS and 8-minute local service in the midday off-peak, and given how slow the local is, it’s enough to tip the scales in favor of walking the entire way if I just miss the bus.

De Blasio Versus Good Transit

In New York, the de Blasio administration has been spending considerable political capital pushing for a $2.5 billion light rail line connecting Astoria and the Brooklyn waterfront south to Sunset Park. There has been a lot of criticism from good transit advocates about implementation – namely, it’s unclear there will be free transfers to the subway and buses, in order to avoid having to share turf with the state-owned MTA – but also of the basic concept, which is not the biggest transit priority in the region, or for matter the twentieth. In comments and on social media, I’ve seen a few wrong arguments made in support of waterfront light rail and similar bad investments over and over, and I’d like to go in some detail into where cities should and should not build such lines.

The principles below are based on various oppositions: first world versus third world, fast versus slow growth, subway versus no subway. I think a good meta-principle is that if the presence of a certain factor is an argument in favor of a specific solution, then its absence should be an argument against that solution. For instance, if high wages are an argument in favor of rail and against bus rapid transit, then low wages should be an argument in favor of bus rapid transit; this principle makes me wonder what Addis Ababa was thinking when it built light rail instead of BRT, while at the same time thinking very little of American cities that make the decision that Addis Ababa should have made. The upshot of the meta-principle is that many of the guidelines that work in New York could work in very different cities, in reverse.

1. New York is a mature first-world city with low population growth; it should build transit exclusively or almost exclusively based on current population and transportation patterns, and not attempt to engage in development-oriented transit. The upzoning the city engages in is too small compared to current population, and cannot justify anything of the magnitude of Vancouver’s Expo Line, which was built simultaneously with Metrotown and the New Westminster offices around the train stations. And even Vancouver cannot reasonably expect the growth rates of various third-world cities with annual population growth rates in the vicinity of 5% and even higher per capita income growth rates.

2. Rail bias is approximately the same on all routes. Routes with many turns and narrow roads have unusually slow buses, but they’ll also have unusually slow surface rail. Rapid transit does have the ability to avoid the extra traffic jams coming from such alignments, and this is especially important in cities where the main street is not the same as the nearby wide boulevard, but this is not what’s under discussion in New York. Yes, de Blasio’s proposed light rail line would get more riders than the buses on segments of the route in question are getting now; the same would be true of any number of light rail routes paralleling the busiest buses in the city.

3. In a city with a subway, the best light rail routes are the ones that don’t make sense as subway extensions. Of the three busiest buses in New York, two make sense as subway lines, so there’s no point building light rail and only later a subway: the M15, on First and Second Avenues, and the B46, on Utica. In contrast, the third route, the Bx12 on Fordham, is crosstown, and cannot reasonably be an extension of any subway line, so it would be a strong light rail corridor. The same can be said of Main Street in Queens, between Flushing and Jamaica; and 14th and 86th Streets in Manhattan, where the M14 and M86 are the busiest surface routes in the US in terms of riders per kilometer, well ahead of the Boston Green Line (they both have about 8,000, and the Green Line 6,000). Of note, 14th Street already hosts the L, but a branch going on Avenue D is far from the subway, and the street is so well-trafficked that despite slower-than-walking bus speeds, that arguably light rail makes sense there even with the subway.

4. As soon as a project is judged as not a top priority, it’s best to think of how useful it is once the top priorities are built. In the case of New York, let us zoom in on Brooklyn’s top two circumferential buses, the B4 B6 and B35. Triboro RX is a higher priority than turning these routes into light rail, and once it’s in place, how much demand is there really going to be for them? It would be faster to take the subway and connect to Triboro, except at very short distances, where speeding up surface traffic is less useful.

In New York, excluding the somewhat special cases of 14th and 86th Streets, I’d say there are three light rail networks that make sense: one in the Bronx, one in Brooklyn, and one in Queens. The Bronx network involves taking the borough’s most frequent buses and turning them into light rail routes: the Bx12 on Fordham as noted above, but also the Bx1/2 on Grand Concourse (like 14th Street, hosting both a subway and a very busy bus route), the Bx19 on Southern and 145th, the Bx15 on Third, and a route on Tremont combining the Bx36 and the Bx40/42. These routes roughly form a grid, each has at least 30,000 weekday riders, and none is SBS except the Bx12. In this case, light rail should really be thought of as the next step after publishing a frequent grid map based on these routes and equipping the entire city bus fleet with off-board fare collection.

In Queens, there’s less room for a grid – the borough has street grids, but it really is based on several old centers, with major roads connecting them. The strongest routes are the ones that cannot reasonably be subway extensions, because they’re too circumferential; in turn, the strongest subway extension, i.e. Northern, is not a major bus route, because it’s close enough to the Queens Boulevard subway that people instead take the subway, which is overcrowded. Of the strong surface transit routes, the corridor with the highest ridership takes in several bus routes between Flushing and Jamaica; Main Street is the most important route, but potentially there’s room both there and on the second route, Kissena-Parsons. Other potential light rail routes radiate from Flushing and Jamaica, in directions not well-served by the subway and the LIRR, or even west on Queens Boulevard to help serve the gap in subway coverage between the 7 and the Queens Boulevard Line and relieve the subway lines.

Brooklyn is the most interesting. The main missing pieces in subway coverage in Brooklyn are good subway extensions: Triboro, Utica, Nostrand. With those in place, the only real gaps are Flatbush, and some route serving Red Hook. Possibly service to the Navy Yard may be desirable, but the area is not very well-developed right now, and the buses serving it have low ridership. Those are two or three routes radiating out of the same center in Downtown Brooklyn, which makes it tempting to not only build light rail on them, but also send it over the Brooklyn Bridge to City Hall. This would be like the subway-surface lines in Boston and San Francisco, where one underground trunk splits into several at-grade branches, except that in this case the trunk would be elevated rather than underground. It’s not worth building by itself, but the possibility of leveraging Brooklyn Bridge lanes for several light rail lines may make the ridership per unit of cost pencil out.

The common factor to all of these possibilities is that they are not meant for signature development areas that the city is targeting. Maybe there’s some new development there, but the focus is on improving public transit services to existing residents, who either are riding very slow buses or have given up on public transit because of the inconvenience. It can be marketed as an improvement in transit, but cannot really be sold as part of a plan to revitalize the Brooklyn waterfront. It’s about day-to-day governing, whereas the administration is interested in urban renewal schemes, which are rarely good transit.

New York’s Subway Frequency Guidelines are the Wrong Approach

In New York, the MTA has consistent guidelines for how frequently to run each subway route, based on crowding levels. The standards are based on crowding levels at the point of maximum crowding on each numbered or lettered route. Each line is designed to have the same maximum crowding, with different systemwide levels for peak and off-peak crowding. While this approach is fair, and on the surface reasonable, it is a poor fit for New York’s highly branched system, and in my view contributes to some of the common failings of the subway.

Today, the off-peak guidelines call for matching frequency to demand, so that at the most crowded, the average train on each route has 25% more passengers than seats. Before the 2010 service cuts, the guidelines had the average train occupied to exact seating capacity. At the peak, the peak crowding guidelines are denser: 110 passengers on cars on the numbered lines, 145 on shorter (60’/18 m) cars on the lettered lines, 175 on longer (75’/23 m) cars on the lettered lines. There’s a minimum frequency of a train every 10 minutes during the day, and a maximum frequency at the peak depending on track capacity. When the MTA says certain lines, such as the 4/5/6, are operating above capacity, what it means is that at maximum track capacity, trains are still more crowded than the guideline.

In reality, guideline loads are frequently exceeded. Before the 2010 service cuts, many off-peak trains still had standees, often many standees. Today, some off-peak trains are considerably fuller than 25% above seated capacity. In this post, I’d like to give an explanation, and tie this into a common hazard of riding the subway in New York: trains sitting in the tunnels, as the conductor plays the announcement, “we are delayed because of train traffic ahead of us.”

The key takeaway from the system is that frequency at each time of day is calculated separately for each numbered or lettered route. Even when routes spend extensive distance interlined, as the 2/3 and 4/5 do, their frequencies are calculated separately. As of December 2014, we have the following headways, in minutes:

Line AM peak Noon off-peak PM peak
1 3 6 4
2 6:30 7:30 6:45
3 6 8:30 6:45
4 4:30 7:30 4:24
5 5 8:30 5:45
6 2:30 4 3:18
7 2:30 5 2:30
A 4:45 10 4:45
B 8:45 10 9:15
C 9:15 10 10
D 6:15 10 6:45
E 4 7:30 4
F 4:45 7:30 5
G 6:30 10 10
J/Z 5 10 5
L 4:30 6 4
M 8:45 10 9:25
N 7:15 10 7:30
Q 7:15 10 7:45
R 7:30 10 7:30

Consider now the shared segments between the various lines. The 4 comes every 4.5 minutes in the morning peak, and the 5 every 5 minutes. There is no way to maintain even spacing on both lines with these headways: they share tracks for an extensive portion of their trip. Instead, the dispatchers move trains around to make sure that headways are as even as possible on both the shared trunk segments and the branches, but something has to give. In 45 minutes, there are ten 4s and nine 5s. Usually, on trunk lines with two branches, trains alternate, but here, it’s not possible to have a perfect alternation in which each 4 is followed by a 5 and each 5 is followed by a 4. There is bound to be a succession of two 4s: the second 4 is going to be less crowded than the guideline, and the following 5 is going to be more crowded.

It gets worse when we consider the extensive reverse-branching, especially on the lettered lines. For example, on its northbound journey, the Q initially does not share tracks with any line; then it shares tracks with the B, into Downtown Brooklyn; then it crosses into Manhattan sharing tracks with the N; then it again shares tracks with no other route, running express in Manhattan while the N runs local; then it shares tracks with the N and R into Queens; and then finally it shares tracks with the N in Queens. It is difficult to impossible to plan a schedule that ensures smooth operations like this, even off-peak, especially when the frequency is so variable.

Concretely, consider what happens when the Q enters Manhattan behind an N. Adequate separation between trains is usually 2 minutes – occasionally less, but the schedule is not robust to even slight changes then. To be able to go to Queens ahead of the N, the Q has to gain 4 minutes running express in Manhattan while the N runs local. Unfortunately, the Q’s express jaunt only skips 4 stations in Manhattan, and usually the off-peak stop penalty is only about 45 seconds, so the Q only gains 3 minutes on the N. Thus, the N has to be delayed at Herald Square for a minute, possibly delaying an R behind it, or the Q has to be delayed 3 minutes to stay behind the N.

In practice, it’s possible to schedule around this problem when schedules are robust. Off-peak, the N, Q, and R all come every 10 minutes, which makes it possible to schedule the northbound Q to always enter Manhattan ahead of the N rather than right behind it. Off-peak, the services they share tracks with – the B, D, and M – all come every 10 minutes as well. The extensive reverse branching still makes the schedule less robust than it can be, but it is at least possible to schedule non-conflicting moves. (That said, the M shares tracks with the much more frequent F.) At the peak, things are much harder: while the N, Q, and R have very similar headways, the D is considerably more frequent, and the B and M considerably less frequent.

I believe that this system is one of the factors contributing to uneven frequency in New York, with all of the problems it entails: crowding levels in excess of guidelines, trains held in the tunnel, unpredictable wait times at stations. Although the principle underlying the crowding guidelines is sound, and I would recommend it in cities without much subway branching, in New York it fails to maintain predictable crowding levels, and introduces unnecessary problems elsewhere.

Instead of planning schedules around consistent maximum crowding, the MTA should consider planning schedules around predictable alternation of services on shared trunk lines. This means that, as far as practical, all lettered lines except the J/Z and the L should have the same frequency, and in addition the 2/3/4/5 should also have the same frequency. The 7 and L, which do not share their track or route with anything else, would maintain the present system. The J/Z, which have limited track sharing with other lines (only the M), could do so as well. The 1 and 6 do not share tracks with other lines, but run local alongside the express 2/3 and 4/5. Potentially, they could run at exactly twice the frequency of the 2/3/4/5, with scheduled timed local/express transfers; however, while this may work for the 6, it would give the 1 too much service, as there is much more demand for express than local service on the line.

To deal with demand mismatches, for example between the E/F and the other lettered lines, there are several approaches, each with its own positives and negatives:

– When the mismatch in demand is not large, the frequencies could be made the same, without too much trouble. The N/Q/R could all run the same frequency. More controversially, so could the 2/3/4/5: there would be more peak crowding on the East Side than on the West Side, but, to be honest, at the peak the 4 and 5 are beyond capacity anyway, so they already are more crowded.

– Some services could run at exactly twice the frequency of other services. This leads to uneven headways on the trunks, but maintains even headways on branches. For example, the A’s peak frequency is very close to exactly twice that of the C, so as they share tracks through Lower Manhattan and Downtown Brooklyn, they could alternate A-C-A-empty slot.

– Services that share tracks extensively could have drastic changes in frequency to each route, preserving trunk frequency. This should be investigated for the E/F on Queens Boulevard: current off-peak frequency is 8 trains per hour each, so cutting the E to 6 and beefing the F to 12 is a possibility.

– Service patterns could be changed, starting from the assumption that every lettered service runs every 10 minutes off-peak and (say) 6-7 minutes at the peak. If some corridors are underserved with just two services with such frequency, then those corridors could be beefed with a third route: for example, the Queens Boulevard express tracks could be supplanted with a service that runs the F route in Jamaica but then enters Manhattan via 53rd Street, like the E, and then continues either via 8th Avenue like the E or 6th Avenue like the M. Already, some peak E trains originate at Jamaica-179th like the F, rather than the usual terminus of Jamaica Center, which is limited to a capacity of 12 trains per hour.

– The service patterns could be drastically redrawn to remove reverse branching. I worked this out with Threestationsquare in comments on this post, leading to a more elegant local/express pattern but eliminating or complicating several important transfers. In particular, the Broadway Line’s N/Q/R trains could be made independent of the Sixth Avenue trains in both Queens and Brooklyn, allowing their frequencies to be tailored to demand without holding trains in tunnels to make frequencies even.

For the lettered lines, I have some affinity for the fourth solution, which at least in principle is based on a service plan from start to finish, rather than on first drawing a map and then figuring out frequency. But it has two glaring drawbacks: it involves more branching than is practiced today, since busy lines would get three services rather than two, making the schedule less robust to delays; and it is so intertwined with crowding levels that every major service change is likely to lead to complete overhaul of the subway map, as entire routes are added and removed based on demand. The second drawback has a silver lining; the first one does not.

I emphasize that this is more a problem of reverse branching than of conventional branching. The peak crowding on all lines in New York, with the exception of the non-branched 7 and 1, occurs in the Manhattan core. Thus, if routes with different colors never shared tracks, it would not be hard to designate a frequency for each trunk route at each time of day, without leading to large mismatches between service and demand. In contrast, reverse branching imposes schedule dependencies between many routes, to the point that all lettered routes except the L have to have the same frequency, up to integer multiples, to avoid conflicts between trains.

The highly branched service pattern in New York leads to a situation in which there is no perfect solution to train scheduling. But the MTA’s current approach is the wrong one, certainly on the details but probably also in its core. It comes from a good place, but it does not work for the system New York has, and the planners should at least consider alternatives, and discuss them publicly. If the right way turns out to add or remove routes in a way that makes it easier to schedule trains, then this should involve extensive public discussion of proposed service maps and plans, with costs and benefits to each community openly acknowledged. It is not good transit to maintain the current scheduling system just because it’s how things have always worked.