Category: High-Speed Rail

Construction Costs: Signaling

I launched a Patreon poll about construction cost posts, offering three options: signaling and electrification, rolling stock, and historical costs. Signaling and electrification won with 29 votes to historical costs’ 20 and rolling stock’s 6. This post covers signaling, and a subsequent post will cover electrification.

I was hoping to have a good database of the cost of installing train protection systems. Instead, I only have a few observations. Most metro lines in the world have searchable construction costs given a few minutes on Google, and a fair number of rolling stock orders are reported alongside their costs on Railway Gazette and other trade publications. In contrast, recent numbers for signaling are hard to get.

The gold standard for mainline rail signaling is European Train Control System, or ETCS; together with a specified GSM communications frequency it forms the European Rail Traffic Management System, or ERTMS. It’s a system designed to replace incompatible national standards that are often nearing the end of their lives (e.g. Germany expects that every person qualified to maintain its legacy LZB system will retire by 2026). It’s of especial interest to high-speed lines, since they are new and must be signaled from scratch based on the highest available standard, and to freight lines, since freight rail competes best over long distances, crossing national borders within Europe. Incompatible standards between countries are one reason why Europe’s freight rail mode share is weaker than that of the US, China, or Russia (which is Eurasian rather than European when it comes to freight rail).

As with every complex IT project, installation has fallen behind expectations. The case of Denmark is instructive. In 2008, Denmark announced that it would install ETCS Level 2 on its entire 2,667-km network by 2020, at the cost of €3.2 billion, or about $1.5 million per route-km. This was because, unlike both of its neighbors, Denmark has a weak legacy rail network outside of the Copenhagen S-tog, with little electrification and less advanced preexisting signaling than LZB. Unfortunately, the project has been plagued with delays, and the most recent timetable calls for completion by 2030. The state has had to additionally subsidize equipping locomotives with ETCS, but the cost is so far low, around $100,000 per locomotive or a little more.

That said, costs in Denmark seem steady, if anything slightly lower than budgeted, thanks to a cheap bid in 2011-2. The reason given for the delay is that Banedanmark changed its priorities and is now focusing on electrification. But contracts for equipping the tracks for ETCS are being let, and the cost per kilometer is about €400,000, or $500,000. The higher cost quoted above, $1.5 million per km, includes some fixed development costs and rolling stock costs.

Outside Denmark, ETCS Level 2 installation continues, but not at a nationwide scale, even in small countries. In 2010, SNCB rejected the idea of near-term nationwide installation, saying that the cost would be prohibitive: €4.68 billion for a network of 3,607 km, about $1.6 million per route-km. This cost would have covered not just signaling the tracks but also modifying interlockings; it’s not purely electronics but also concrete.

The Netherlands is planning extensive installation as well. As per Annex V of an EU audit from last year (PDF-pp. 58-59), the projected cost is around $2 million per route-km; the same document also endorses Denmark’s original budget, minus a small reduction as detailed above due to unexpectedly favorable bids. Locomotive costs are said to be not about $100,000 but €300,000 for new trainsets or €500,000 for retrofitting older trainsets.

A cheaper version, ETCS Level 1, is also available. I do not know its cost. Switzerland is about to complete the process of a nationwide installation. It permits a trainset equipped with just ETCS equipment and no other signaling to use the tracks, improving interoperability. However, it is an overlay on preexisting systems, so it is only a good fit in places with good preexisting signaling. This includes Switzerland, Germany, and France, but not Denmark or other countries with weak legacy rail networks, including the US. The Northeast Corridor’s ACSES system is similar to ETCS Level 1, but it’s an overlay on top of a cab signaling system installed by the Pennsylvania Railroad in the 1930s.

Comparing this with American costs is difficult. American positive train control, or PTC, uses lower-capacity overlay signaling, nothing like ETCS Level 2. One article claims that the cost per track-km (not route-km) on US commuter rail is about $260,000. On the MBTA, the projected cost is $517 million for 641 km, or $800,000 per route-km; on the LIRR it’s $1 billion for 513 route-km, or $1.9 million per route-km. Observe that the LIRR is spending about as much on a legacy tweak as Denmark and the Netherlands are on a high-capacity system built from scratch.

Why Northeast Corridor Privatization is Doomed to Failure

Alex Armlovich asked me whether it’s possible to design a public-private partnership on the Northeast Corridor (NEC) to build high-speed rail. I took it to a Patreon poll, in which it prevailed over three other options (why land value taxation is overrated, why community groups oppose upzoning, and what examples of transit success there are in autocracies). On social media I gave a brief explanation for why such a privatization scheme would fail: the NEC has many users sharing tracks, requiring coordination of schedules and infrastructure, and privatizing one component would create incentives for rent-seeking rather than good work. In this post I am going to explain this more carefully.

Conceptually, the impetus for privatization is that the public sector cannot provide certain things successfully because it is politically controlled. For example, political control of infrastructure tends to lead to spreading investment around across a number of regions rather than where it is most needed; when Japan National Railways was broken up and privatized, the new companies let go of many lightly-used rural lines and focused on the urban commuter rail networks and the Shinkansen. Political control may also make it harder to keep down headcounts or wages. A competent government that recognizes that it will always be subject to political decisionmaking about services that should not be political will aim to devolve control of these services to the private sector.

The problem with this story is that privatization itself is a public program. This means that the government needs to be in good enough shape to write a PPP that encourages good service and discourages rent-seeking. Such a government entity does not exist in the realm of American public transportation. This doesn’t mean that all privatization deals are bad, but it means that only the simplest deals have any chance of success, and those deals in turn have the least impact.

When it comes to HSR, private operations work provided there is no or almost no need to coordinate schedules and fares with anyone else. One example is Texas, which has no commuter rail between Dallas and Houston nor any good reason to ever run such service. In California, this is also more or less the case: Caltrain-HSR compatibility is needed, but that’s a small portion of the line and could be resolved relatively easily.

In the Northeast, where there is extensive commuter rail, such coordination is indispensable. Without it, any operator has an incentive to make life miserable for the commuter rail operators and then demand state subsidies to allow regional trains on the track. Amtrak is already screwing other NEC users by charging high rates for electricity (which is supposedly the reason Conrail deelectrified, having previously run freight service on the NEC with electric locomotives) and by coming up with infrastructure plans that make regional rail modernization harder and demanding state money for them. If anything, the political control makes things less bad, because congressional representatives can yell at Amtrak; they will have less leverage over a private operator. In the other direction, Metro-North is slowing down Amtrak between New Rochelle and New Haven for the convenience of its own dispatching, and is likely to keep doing so under any PPP deal.

I have written many posts about what it would take to institute HSR on the NEC at the lowest possible cost. All of these make the same point, from many angles: organization – that is, improving timetabling – is vastly cheaper than pouring concrete and building bypass tracks. In chronological order, I’ve written,

Privatization is supposed to solve the problems of an incompetent public sector. But Amtrak’s incompetence is not really about wages or staffing; NEC trains are overstaffed relative to Shinkansen trains, but not relative to TGVs. Nor is it about unprofitable branch lines, not when the proposal is to privatize the NEC alone, rather than the entirety of Amtrak so that the private operator could shut down the long-distance trains. Some of the incompetence involves politicized procurement, but this is not the dominant source of high NEC costs. No: the incompetence manifests itself first of all in poor coordination between the various users of the NEC. Given better coordination, Amtrak could shave a substantial portion of its New York-New Haven runtime, perhaps by 10-20 minutes without any bridge replacements, and reduce schedule padding elsewhere.

To fix this situation, some organization would need to determine the timetables up and down the line and handle dispatching and train priority. In the presence of such an organization (which could well be Amtrak itself given top-to-bottom changes in management), a PPP is of limited benefit, because the private operator would be running on a schedule set publicly. Absent such an organization, privatization would make the agency turf battles that plague the entire NEC even worse than they are today.

In 2009, SNCF proposed to develop HSR in four places in the US: California, Texas, Florida, and the Midwest. The NEC, with its existing public intercity and regional rail operations, was not on its map. More recently, Texas Central is a private Japanese initiative to build HSR between Dallas and Houston. On the NEC the only Japanese initiative involved maglev between Washington and Baltimore, a mode of transportation that doesn’t fit the NEC’s context but is guaranteed to not share tracks with any state-owned commuter rail operation.

The invention of HSR itself was not privatized, and the European privatization paradigm involves public control of track infrastructure. Competing operators (some public, some private) can access tracks by paying a track charge, set equally across all operators. But even then, the track infrastructure owner has some decisions to make about design speed – mixing slower and faster trains reduces capacity, so if there’s a mixture of both, does the infrastructure owner assume the design speed is high and charge slower trains extra for taking high-speed slots or does it assume the design speed is low and charge faster trains extra? So far the public rail infrastructure operators have swept this question under the rug, relying on the fact that on high-speed tracks all trains go fast and on low-speed ones few HSR services go faster than an express regional train.

Unfortunately, the NEC requires large speed differences on the same route to avoid excessive tunneling. This complicates the EU’s attempts at a relatively hands-off approach to rail competition in two ways. First, it’s no longer possible to ignore the design speed question, not when regional trains should be connecting Boston and Providence in 51 minutes and high-speed trains in 20 minutes, on shared tracks with strategic overtakes. And second, the overtakes must be timed more precisely, which means whoever controls the tracks needs to also take an active hand in planning the schedules.

Handwaving the problems of the public sector using privatization works in some circumstances, such as those of Japan National Railways, but could never work on the NEC. The problems a PPP could fix, including labor and rolling stock procurement, are peripheral; the problems it would exacerbate, i.e. integrating infrastructure and schedule planning, are the central issues facing the NEC. There is no alternative to a better-run, better-managed state-owned rail planning apparatus.

What the Spinetta Axe Reveals About Cost Control

The Macron administration commissioned a report about the future of SNCF by former Air France chief Jean-Cyril Spinetta. Spinetta released his report four days ago, making it clear that rail is growing in France but most of the network is unprofitable and should be shrunk. There is an overview of the report in English on Railway Gazette, and some more details in French media (La Tribune calls it “mind-blowing,” Les Echos “explosive”); the full proposal can be read here. Some of the recommendations in the Spinetta report concern governance, but the most radical one calls for pruning about 45% of SNCF’s network by length, which carries only 2% of passenger traffic. Given the extent of the proposed cut, it’s appropriate to refer to this report as the Spinetta Axe, in analogy with the Beeching Axe.

I wrote a mini-overview on Twitter, focusing on the content of the Axe. In this post I’m going to do more analysis of SNCF’s cost control problem and what we can learn from the report. The big takeaway is that cost control pressure is the highest on low-ridership lines, rather than on high-ridership lines. There is no attempt made to reduce SNCF’s operating costs in Ile-de-France or on the intercity main lines through better efficiency. To the British or American reader, it’s especially useful to read the report with a critical eye, since it is in some ways a better version of British and American discussions about efficiency that nonetheless accept high construction costs as a given.

SNCF is Losing Money

The major problem that the report begins with is that SNCF is losing money. It is not getting state subsidies, but instead it borrows to fund operating losses, to the tune of €2.8 billion in annual deficit (p. 28), of which €1.2-1.4 billion come from interest expenses on past debt and €1 billion come from taxes. Its situation is similar to that of Japan National Railways in the 1970s, which accumulated debt to fund operating losses, which the state ultimately wiped out in the restructuring and privatization of 1987. The report is aiming to find operating savings to put SNCF in the black without breaking up or privatizing the company; its proposed change to governance (turning SNCF into an SA) is entirely within the state-owned sector.

Unlike the Beeching report, the Spinetta report happens in a context of rising rail traffic. It opens up by making it clear that rail is not in decline in France, pointing out growth in both local and intercity ridership. However, SNCF is still losing money, because of the low financial performance of the legacy network and regional lines. The TGV network overall is profitable (though not every single train is profitable), but the TERs are big money pits. Annual regional contributions to the TER network total €3 billion, compared with just €1 billion in fare revenue (p. 30). The legacy intercity lines, which are rebranded every few years and are now called TETs, lose another €300 million. Some of the rising debt is just capital expenses that aren’t fully funded, including track renovation and new rolling stock; even in the Paris region, which has money, rolling stock purchase has only recently been devolved from SNCF to the regional transport association (p. 31).

In fact, the large monetary deficit is a recent phenomenon. In 2010, SNCF lost €600 million, but paid €1.2 billion in interest costs (p. 27); its operating margin was larger than its capital expenses. Capital expenses have risen due to increase in investment, while the operating margin has fallen due to an increase in operating costs. The report does not go into the history of fares (it says French rail fares are among Europe’s lowest, but its main comparisons are very high-fare networks like Switzerland’s, and in reality France is similar to Germany and Spain). But it says fares have not risen, for which SNCF’s attempt to provide deliberately uncomfortable lower-fare trains must share the blame.

The Spinetta Axe

The Spinetta report proposes multiple big changes; French media treats converting SNCF to an SA as a big deal. But in terms of the network, the biggest change is the cut to low-performing rail branches. The UIC categorizes rail lines based on traffic levels and required investment, from 1 (highest) to 9 (lowest). Categories 7-9 consist of 44% of route-km but only 9% of train-km (p. 48) and 2% of passengers (p. 51). Annual capital and operating spending on these lines is €1.7 billion (about €1 per passenger-km), and bringing them to a state of good repair would cost €5 billion. In contrast, closing these lines would save €1.2 billion a year.

But the report is not just cuts. Very little of SNCF’s operating expenditure is marginal: on p. 34 the report claims that marginal operating costs only add up to €1 billion a year, out of about €5.5 billion in total operating costs excluding any and all capital spending. As a result, alongside its recommendations to close low-ridership lines, it is suggesting increasing off-peak frequency on retained lines (p. 54, footnote 53).

There is no list of which lines should be closed; this is left for later. Page 50 has a map of category 7-9 lines, which are mostly rural branch lines, for example Nice-Breil-Tende. But a few are more intense regional lines, around Lyon, Toulouse, Rennes, Lille, and Strasbourg, and would presumably be kept and maintained to higher standards. Conversely, some category 5-6 lines could also be closed.

The report is equally harsh toward the TGV. While the TGV is overall profitable, not all parts of it are competitive. Per the report, the breakeven point with air travel, on both mode share and operating costs, is 3 hours one-way. At 3:30-4 hours one way, the report describes the situation for trains as “brutal,” with planes getting 80% mode share (p. 61). With TGV operating costs of €0.06/seat-km without capital (€0.07 with), it is uncompetitive on cost with low-cost airlines beyond 700 km, where EasyJet and Air France can keep costs down to €0.05/seat-km including capital and Ryanair to €0.04.

And this is where the report loses me. The TGV’s mode share versus air is consistently higher than that given in the report. One study imputes a breakeven point at nearly 4 hours. A study done for the LGV PACA, between Marseille and Nice, claims that as of 2009, the TGV had a 30% mode share on Paris-Nice, even including cars; its share of the air-rail market was 38%. This is a train that takes nearly 6 hours and was delayed three out of four times I took it, and the fourth time only made it on time because its timetable was unusually padded between Marseille and Paris. On Paris-Toulon, where the TGV takes about 4 hours, its mode share in 2009 was 54%, or 82% of the air-rail market.

SNCF has some serious operating cost issues. For example, the conventional TGVs (i.e. not the low-cost OuiGo) have four conductors per 200-meter train; the Shinkansen has three conductors per 400-meter train. The operating costs imputed from the European and East Asian average in American studies are somewhat lower, about $0.05-6/seat-km, or about €0.04-5/seat-km, making HSR competitive with low-cost airlines at longer range. However, there is no attempt to investigate how these costs can be reduced. One possibility, not running expensive TGVs on legacy lines but only on high-speed lines, is explicitly rejected (p. 64), and rightly so – Rennes, Toulouse, Mulhouse, Toulon, Nice, and Nantes are all on legacy lines.

This is something SNCF is aware of; it’s trying to improve fleet utilization to reduce operating costs by 20-30%. With higher fleet utilization, it could withdraw most of its single-level trains and have a nearly all-bilevel fleet, with just one single-level class, simplifying maintenance and interchangeability in similar manner to low-cost carriers’ use of a single aircraft class. However, this drive is not mentioned at all in the report, which takes today’s high costs as a given.

Efficiencies not Mentioned

The biggest bombshell I saw in the report is not in the recommendations at all. It is not in the Spinetta Axe, but in a table on p. 21 comparing SNCF with DB. The two networks are of similar size, with DB slightly larger, 35,000 route-km and 52,000 track-km vs. 26,000 and 49,000 on SNCF. But DB’s annual track maintenance budget is €1.4 billion whereas SNCF’s is €2.28 billion. Nearly the entire primary deficit of SNCF could be closed just by reducing track maintenance costs to German levels, without cutting low-usage lines.

Nonetheless, there is no investigation of whether it’s possible to conduct track maintenance more efficiently. Here as with the TGV’s operating expenses, the report treats unit costs as a fixed constant, rather than as variables that depend on labor productivity and good management.

Nor is there any discussion of rolling stock costs. Paris’s bespoke RER D and E trains, funded locally on lines to be operated by SNCF, cost €4.7 million per 25 meters of train length, with 30% of this cost going to design and overheads and only 70% to actual manufacturing. In Sweden, the more standard KISS cost €2.9 million per 25-meter car.

Low-ridership dilapidated rural branch lines are not the only place in the network where it’s possible to reduce costs. Rolling stock in Paris costs too much, maintenance on the entire network costs too much, TGV operating costs are higher than they should be, and fleet utilization in the off-peak is very low. The average TGV runs for 8 hours a day, and SNCF hopes to expand this to 10.

The Impetus for Cost Control

The Beeching Axe came in the context of falling rail traffic. The Spinetta Axe comes in the context of rapidly growing SNCF operating costs, recommending things that could and probably should have been done ten years ago. But ten years ago, SNCF had a primary surplus and there was no pressure to contain costs. By the same token, the report is recommending pruning the weakest lines, but ignores efficiencies on the strong lines, on the “why mess with what works?” idea.

The same effect is seen regionally. French rolling stock costs do not seem unusually high outside Paris. But Ile-de-France has money to waste, so it’s spending far too much on designing new rolling stock that nobody else has any use for. This is true outside France as well: the high operating costs of the subway in New York are not a US-wide phenomenon, but rather are restricted to New York, Boston, and Los Angeles, while the rest of the country, facing bigger cost pressure than New York and Boston, is forced to run trains for the same cost as the major European cities. It is also likely that New York (and more recently London) allowed its construction costs to explode to extreme levels because, with enough money to splurge on high-use lines like 63rd Street Tunnel and Second Avenue Subway, it never paid attention to cost control.

This approach to cost control is entirely reactive. Places with high operating or capital costs don’t mind these costs when times are good, and then face crisis when times are bad, such as when the financial crisis led to stagnation in TGV revenue amidst continued growth in operating costs, or when costs explode to the point of making plans no longer affordable. In crisis mode, a gentle reduction in costs may not be possible technically or politically, given pressure to save money fast. Without time to develop alternative plans, or learn and adopt best industry practices, agencies (or private companies) turn to cuts and cancel investment plans.

A stronger approach must be proactive. This means looking for cost savings regardless of the current financial situation, in profitable as well as unprofitable areas. If anything, rich regions and companies are better placed for improving efficiency: they have deep enough pockets to finance the one-time cost of some reforms and to take their time to implement reforms correctly. SNCF is getting caught with its pants down, and as a result Spinetta is proposing cuts but nothing about reducing unit operating and maintenance costs. Under a proactive approach, the key is not to get caught with your pants down in the first place.

High-Speed Rail from New Rochelle to Greens Farms: Impacts, Opportunities, and Analysis

I was asked by Greg Stroud of SECoast to look at HSR between New Rochelle and Greens Farms. On this segment (and, separately, between Greens Farms and Milford), 300+ km/h HSR is not possible, but speedups and bypasses in the 200-250 area are. The NEC Future plan left the entire segment from New York to New Haven as a question mark, and an inside source told me it was for fear of stoking NIMBYism. Nonetheless, SECoast found a preliminary alignment sketched by NEC Future and sent it to me, which I uploaded here in Google Earth format – the file is too big to display on Google Maps, but you can save and view it on your own computer. Here’s my analysis of it, first published on SECoast, changed only on the copy edit level and on English vs. metric units.

The tl;dr version is that speeding up intercity trains (and to some extent regional trains too) on the New Haven Line is possible, and requires significant but not unconscionable takings. The target trip time between New York and New Haven is at the lower end of the international HSR range, but it’s still not much more than a third of today’s trip time, which is weighed down by Amtrak/Metro-North agency turf battles, low-quality trains, and sharp curves.

The New Haven Line was built in the 1840s in hilly terrain. Like most early American railroads, it was built to low standards, with tight curves and compromised designs. Many of these lines were later replaced with costlier but faster alignments (for example, the Northeast Corridor in New Jersey and Pennsylvania), but in New England this was not done. With today’s technology, the terrain is no problem: high-speed trains can climb 3.5-4% grades, which were unthinkable in the steam era. But in the 170 years since the line opened, many urban and suburban communities have grown along the railroad right of way, and new construction and faster alignments will necessarily require significant adverse impacts to communities built along the Northeast Corridor.

This analysis will explain some of the impacts and opportunities expanding and modernizing high-speed rail infrastructure on or near the New Haven Line—and whether such an investment is worthwhile in the first place. There are competing needs: low cost, high speed, limited environmental impact, good local service on Metro-North. High-speed rail can satisfy each of them, but not everywhere and not at the same time.

The Northeast Corridor Future (NEC Future) preferred alternative, a new plan by the Federal Railroad Administration to modernize and expand rail infrastructure between Washington and Boston, proposes a long bypass segment parallel to the New Haven Line, between Rye and Greens Farms. The entire segment is called the New Rochelle-Greens Farms bypass; other segments are beyond the scope of this document.

Structure and Assumptions

The structure of this write-up is as follows: first, technical explanations of the issues with curves, with scheduling commuter trains and high-speed trains on the same track, and with high-speed commuting. Then, a segment-by-segment description of the options:

  • New Rochelle-Rye, the leadup to the bypass, where scheduling trains is the most difficult.
  • Rye-Cos Cob, the first bypass.
  • The Cos Cob Bridge, a decrepit bridge for which the replacement is worth discussing on its own.
  • Cos Cob-Stamford, where the preferred alternative is a bypass, but a lower-impact option on legacy track is as fast and should be studied.
  • Stamford-Darien, where another bypass is unavoidable, with significant residential takings, almost 100 houses in one possibility not studied in the preferred alternative.
  • Norwalk-Greens Farms, a continuation of the Darien bypass in an easier environment.

The impacts in question are predominantly noise, and the effect of takings. The main reference for noise emissions is a document used for California High-Speed Rail planning, using calibrated noise levels provided by federal regulators. At 260 km/h, higher than trains could attain in most of the segment in question, trains from the mid-1990s 45 meters away would be comparable to a noisy urban residential street; more recent trains, on tracks with noise barriers, would be comparable to a quiet urban street. Within a 50-meter (technically 150 feet) zone, adverse impact would require some mitigation fees.

At higher speed than 260 km/h, the federal regime for measuring train noise changes: the dominant factor in noise emissions is now air resistance around the train rather than rolling friction at the wheels. This means two things: first, at higher speed, noise emissions climb much faster than before, and second, noise barriers are less effective, since the noise is generated at the nose and pantograph rather than the wheels. At only one place within the segment are speeds higher than about 260 km/h geometrically feasible, in Norwalk and Westport, and there, noise would need to be mitigated with tall trees and more modern, aerodynamic trains, rather than with low concrete barriers.

This analysis excludes impact produced by some legacy trains, such as the loud horns at grade crossings; these may well go away in a future regulatory reform, as the loud horns serve little purpose, and the other onerous federal regulations on train operations are being reformed. But in any case, the mainline and any high-speed bypass would be built to high standards, without level crossings. Thus noise impact is entirely a matter of loud trains passing by at high speed.

Apart from noise and takings, there are some visual impacts coming from high bridges and viaducts. For the most part, these are in areas where the view the aerials block is the traffic on I-95. Perhaps the biggest exception is the Mianus River, where raising the Cos Cob Bridge has substantial positive impact on commuter train operations and not just intercity trains.


The formula for the maximum speed on a curve is as follows:

\mbox{Speed}^2 = (\mbox{Curve radius}) \times (\mbox{Lateral acceleration})

If all units are metric, and speed is in meters per second, this formula requires no unit conversion. But as is common in metric countries, I will cite speed in kilometers per hour rather than meters per second; 1 m/s equals 3.6 km/h.

Lateral acceleration is the most important quantity to focus on. It measures centrifugal force, and has a maximum value for safety and passenger comfort. But railroads decompose it into two separate numbers, to be added up: superelevation (or cant), and cant deficiency (or unbalanced superelevation, or underbalance).

Superelevation means banking the tracks on a curve. There is an exact speed at which trains can run where the centrifugal force exactly cancels out the banking, but in practice trains tend to run faster, producing additional centrifugal force; this additional force is called cant deficiency, and is measured as the additional hypothetical cant required to exactly balance.

If a train sits still on superelevated track, or goes too slowly, then passengers will feel a downward force, toward the inside of the curve; this is called cant excess. On tracks with heavy freight traffic, superelevation is low, because slow freight trains would otherwise be at dangerous cant excess. But the New Haven Line has little freight traffic, all of which can be accommodated on local tracks in the off-hours, and thus superelevation can be quite high. Today’s value is 5” (around 130 mm), and sometimes even less, but the maximum regulatory value in the United States is 7” (around 180 mm), and in Japan the high-speed lines can do 200 mm, allowing tighter curves in constrained areas.

Cant deficiency in the United States has traditionally been very low, at most 3” (75 mm). But modern trains can routinely do 150 mm, and Metro-North should plan on that as well, to increase speed. The Acela has a tilting mechanism, allowing 7”; the next-generation Acelas are capable of 9” cant deficiency (230 mm) at 320 km/h; this document will assume the sum total of cant and cant deficiency is 375 mm (the new Acela trainsets could do 200 mm cant deficiency with 175 mm cant, or Japanese trainsets could do 175 mm cant deficiency with 200 mm cant). This change alone, up from about 200 mm today, enough to raise the maximum speed on every curve by 37%. At these higher values of superelevation and cant deficiency, a curve of radius 800 meters can support 160 km/h.

Scheduling and Speed

The introduction of high-speed rail between New York and New Haven requires making some changes to timetabling on the New Haven Line. In fact, on large stretches of track on this line, especially in New York State, the speed limit comes not from curves or the physical state of the track, but from Metro-North’s deliberately slowing Amtrak down to the speed of an express Metro-North train, to simplify scheduling and dispatching. This includes both the top speed (90 mph/145 km/h in New York State, 75 mph/120 km/h in Connecticut) and the maximum speed on curves (Metro-North forbids the Acela to run at more than 3”/75 mm cant deficiency on its territory).

The heart of the problem is that the corridor needs to run trains of three different speed classes: local commuter trains, express commuter trains, and intercity trains. Ideally, this would involve six tracks, two per speed class, much like the four-track mainlines with two speed classes on the subway in New York (local and express trains). However, there are only four tracks. This means that there are four options:

  1. Run only two speed classes, slowing down intercity trains to the speed of express commuter trains.
  2. Run only two speed classes, making all commuter trains local.
  3. Expand the corridor to six tracks.
  4. Schedule trains of three different speed classes on just four tracks, with timed overtakes allowing faster trains to get ahead of slower trains at prescribed locations.

The current regime on the line is option #1. Option #2 would slow down commuters from Stamford and points east too much; the New Haven Line is too long and too busy for all-local commuter trains. Option #3 is the preferred alternative; the problem there is the cost of adding tracks in constrained locations, which includes widening viaducts and rebuilding platforms.

Option #4 has not been investigated very thoroughly in official documents. The reason is that timed overtakes require trains to be at a specific point at a specific time. Amtrak’s current reliability is too poor for this. However, future high-speed rail is likely to be far more punctual, with more reliable equipment and infrastructure. Investing in this option would require making some targeted investments toward reliability, such as more regular track and train maintenance, and high platforms at all stations in order to reduce the variability of passenger boarding time.

Moreover, at some locations, there are tight curves on the legacy New Haven Line that are hard or impossible to straighten in any alignment without long tunnels. South of Stamford, this includes Rye-Greenwich.

This means that, with new infrastructure for high-speed rail, the bypass segments could let high-speed trains overtake express commuter trains. The Rye-Greenwich segment is especially notable. High-speed rail is likely to include a bypass of Greenwich station. Thus, express commuter trains could stop at Greenwich, whereas today they run nonstop between Stamford and Manhattan, in order to give intercity trains more time to overtake them. A southbound high-speed trains would be just behind an express Metro-North train at Stamford, but using the much greater speed on the bypass, it would emerge just ahead of it at Rye. This segment could be built separately from the rest of the segment, from Stamford to Greens Farms and beyond, because of its positive impact on train scheduling.

It is critical to plan infrastructure and timetable together. With a decision to make express trains stop at Greenwich, infrastructure design could be simpler: there wouldn’t be a need to add capacity by adding tracks to segments that are not bypassed.

High-Speed Commuting

A junior consultant working on NEC Future who spoke to me on condition of anonymity said that there was pressure not to discuss fares, and at any rate the ridership model was insensitive to fare.

However, this merits additional study, because of the interaction with commuter rail. If the pricing on high-speed rail is premium, as on Amtrak today, then it is unlikely there will be substantial high-speed commuting to New York from Stamford and New Haven. But if there are tickets with low or no premium over commuter rail, with unreserved seating, then many people would choose to ride the trains from Stamford to New York, which would be a trip of about 20 minutes, even if they would have to stand.

High-speed trains are typically longer than commuter trains: 16 cars on the busier lines in Japan, China, and France, rather than 8-12. This is because they serve so few stops that it is easier to lengthen every platform. This means that the trains have more capacity, and replacing a scheduled commuter train with a high-speed train would not compromise commuter rail capacity.

The drawback is that commuters are unlikely to ride the trains outside rush hour, which only lasts about 2 or 3 hours a day in each direction. In contrast, intercity passengers are relatively dispersed throughout the day. Capital investment, including infrastructure and train procurement, is based on the peak; reducing the ratio of peak to base travel reduces costs. The unreserved seat rule, in which there is a small premium over commuter rail for unreserved seats (as in Germany and Japan) and a larger one for reserved seats, is one potential compromise between these two needs (flat peak, and high-speed commuter service).

New Rochelle-Rye

The track between New Rochelle and Rye is for the most part straight. Trains go 145 km/h, and this is because Metro-North slows down intercity trains for easier dispatching. The right-of-way geometry is good for 180 km/h with tilting trains and high superelevation; minor curve modifications are possible, but save little time. The big item in this segment concerns the southern end: New Rochelle.

At New Rochelle, the mainline branches in two: toward Grand Central on the New Haven Line, and toward Penn Station on the Hell Gate Line, used by Amtrak and future Penn Station Access trains. This branching is called Shell Interlocking, a complex of track switches, all at grade, with conflicts between trains in opposite directions. All trains must slow down to 30 mph (less than 50 km/h), making this the worst speed restriction on the Northeast Corridor outside the immediate areas around major stations such as Penn Station and Philadelphia 30th Street Station, where all trains stop.

The proposed (and only feasible) solution to this problem involves grade-separating the rails using flyovers, a project discussed by the FRA at least going back to 1978 (PDF-p. 95). This may involve some visual impact, or not—there is room for trenching the grade-separation rather than building viaducts. It is unclear how much that would cost, but a flyover at Harold Interlocking in Queens for East Side Access, which the FRA discussed in the same report, cost $300 million dollars earlier this decade. Harold is more complex than Shell, since it has branches on both sides and is in a more constrained location; it is likely that Shell would cost less than Harold’s $300 million. Here is a photo of the preferred alignment:

The color coding is, orange is viaducts (including grade separations), red is embankments, and teal is at-grade. This is the Northeast Corridor, continuing south on the Hell Gate Line to Penn Station, and not the Metro-North New Haven Line, continuing west (seen in natural color in the photo) to Grand Central.

A Shell fix could also straighten the approach from the south along the Hell Gate Line, which is curvy. The curve is a tight S, with individual curves not too tight, but the transition between them constraining speed. The preferred alignment proposes a fix with a kilometer of curve radius, good for 180 km/h, with impact to some industrial sites but almost no houses and no larger residential buildings. It is possible to have tighter curves, at slightly less cost and impact, or wider ones. Slicing a row of houses in New Rochelle, east of the southern side of the S, could permit cutting off the S-curve entirely, allowing 240 km/h; the cost and impact of this slice relative to the travel time benefit should be studied more carefully and compared with the cost per second saved from construction in Connecticut.

The main impact of high-speed rail here on ordinary commuters is the effect on scheduling. With four tracks, three train speed classes, and heavy commuter rail traffic, timetabling would need to be more precise, which in turn would require trains to be more punctual. In the context of a corridor-wide high-speed rail program, this is not so difficult, but it would still constrain the schedule.

Without additional tracks, except on the bypasses, there is capacity for 18 peak Metro-North trains per hour into New York (including Penn Station Access) and 6 high-speed trains. Today’s New Haven Line peak traffic is 20 trains per hour (8 south of Stamford, 12 north of which 10 run nonstop from Stamford to Manhattan), so this capacity pattern argues in favor of pricing trains to allow commuters to use the high-speed trains between Stamford and New York.


Rye is the first place, going from the south, where I-95 is straighter than the Northeast Corridor. This does not mean it is straight: it merely means that the curves on I-95 in that area are less sharp than those at Rye, Port Chester, and Greenwich. Each of these three stations sits at a sharp S-curve today; the speed zone today is 75 mph (120 km/h), with track geometry that could allow much more if Metro-North accepted a mix of trains of different speed, but Rye and Greenwich restrict trains to 60 mph/95 km/h, and Port Chester to 45 mph/70 km/h at the state line. The segment between the state line and Stamford in particular is one of the slowest in the corridor.

As a result, the NEC Future plan would bypass the legacy line there alongside the Interstate. Currently, the worst curve in the bypassed segment, at Port Chester, has radius about 650 meters, with maximum speed much less than today’s trains could do on such a curve because of the sharp S. At medium and high speed, it takes a few seconds of train travel time to reverse a curve, or else the train must go more slowly, to let the systems as well as passengers’ muscles adjust to the change in the direction of centrifugal force. At Rye, the new alignment has 1,200-meter curves, with gentle enough S to allow trains to fully reverse, without additional slowdowns; today’s tracks and trains could take it at 140 km/h, but a tilting train on tracks designed for higher-speed travel could go up to 195.

Within New York State, the bypass would require taking a large cosmetics store, and some houses adjacent to I-95 on the west; a few townhouses in Rye may require noise walls, as they would be right next to the right-of-way where trains would go about 200-210 km/h, but at this speed the noise levels with barriers are no higher than those of the freeway, so the houses would remain inhabitable.

In Connecticut, the situation is more delicate. When the tracks and I-95 are twinned, there is nothing in between, and thus the bypass is effectively just two extra tracks. To the south, just beyond the state line, the situation is similar to that of Rye: a few near-freeway houses would be acquired, but nothing else would, and overall noise levels would not be a problem.

But to the north, around Greenwich station, the proposed alignment follows the I-95 right-of-way, with no residential takings, and one possible commercial taking at Greenwich Plaza. This alignment comes at the cost of a sharp curve: 600 meters, comparable to the existing Greenwich curve. This would provide improvements in capacity, as intercity trains could overtake express commuter trains (which would also stop at Greenwich), but not much in speed.

Increasing speed requires a gentler curve than on I-95; eliminating the S-curve entirely would raise the radius to about 1,600 meters, permitting 225 km/h. This has some impact, as the inside of the curve would be too close to the houses just south of I-95, requiring taking about seven houses.

However, the biggest drawback of this gentler curve is cost: it would have to be on a viaduct crossing I-95 twice, raising the cost of the project. It is hard to say by exactly how much: either option, the preferred one or the 225 km/h option, would involve an aerial, costing about $100 million according to FRA cost items, so the difference is likely to be smaller than this. It is a political decision whether saving 30 seconds for express trains is worth what is likely to be in the low tens of millions of dollars.

Cos Cob Bridge

The Cos Cob Bridge restricts the trains, in multiple ways. As a movable bridge, it is unpowered: trains on it do not get electric power, but must instead coast; regular Metro-North riders are familiar with the sight of train lights, air conditioning, and electric sockets briefly going out when the train is on the bridge. It is also old enough that the structure itself requires trains to go more slowly, 80 km/h in an otherwise 110 km/h zone.

Because of the bridge’s age and condition, it is a high priority for replacement. One cost estimate says that replacing the bridge would cost $800 million. The Regional Plan Association estimates the cost of replacing both this bridge and the Devon Bridge, at the boundary between Fairfield and New Haven Counties, at $1.8 billion. The new span would be a higher bridge, fully powered, without any speed limit except associated with curves; Cos Cob station has to be rebuilt as well, as it is directly on the approaches, and it may be possible to save money there (Metro-North station construction costs are very high—West Haven was $105 million, whereas Boston has built infill stations for costs in the teens).

In any high-speed rail program, the curves could be eased as well. There are two short, sharp curves next to the bridge, one just west to the Cos Cob station and the other between the bridge and Riverside. The replaced bridge would need long approaches for the deck to clear the Mianus River with enough room for boats to navigate, and it should not cost any more in engineering and construction to replace the two short curves with one long, much wider curve. There is scant information about the proposed clearance below and the grades leading up to the bridge, but both high-speed trains and the high-powered electric commuter trains used by Metro-North can climb steep grades, up to 3.5-4%, limiting the length of the approaches to about 400 meters on each side. This is the alternative depicted as the potential alternative below; the Cos Cob Bridge is the legacy bridge, and the preferred alignment is a different bypass (see below for the Riverside-Stamford segment):

The color coding is the same as before, but yellow means major bridge. White is my own drawing of an alternative.

The radius of the curve would be 1,700 meters. A tilting train could go at 235 km/h. Commuter rail would benefit from increased speed as well: express trains could run at their maximum speed, currently 160 km/h, continuing almost all the way east to Stamford. The cost of this in terms of impact is the townhouses just north of the Cos Cob station: the viaduct would move slightly north, and encroach on some, possibly all, of the ten buildings. Otherwise, the area immediately to the north of the station is a parking lot.

The longer, wider curve alternative can be widened even further. In that case, there would be more impact on the approaches, but less near the bridge itself, which would be much closer in location to the current bridge and station. This option may prove useful if one alignment for the wider curve turns out to be infeasible due to either unacceptable impact to historic buildings or engineering difficulties. The curve radius of this alternative rises to about 3,000 meters, at which point the speed limit is imposed entirely by neighboring curves in Greenwich and Stamford; trains could go 310 km/h on a 3,000-meter curve, but they wouldn’t have room to accelerate to that speed from Greenwich’s 225 km/h.


Between the Mianus River and Stamford, there are two possible alignments. The first is the legacy alignment; the second is a bypass alongside I-95, which would involve a new crossing of the Mianus River as well. The NEC Future alignment appears to prefer the I-95 option:

The main benefit of the I-95 option is that it offers additional bypass tracks for the New Haven Line. Under this option, there is no need for intercity trains and express commuter trains to share tracks anywhere between Rye and Westport.

However, the legacy alignment has multiple other benefits. First, it has practically no additional impact. Faster trains would emit slightly more noise, but high-speed trains designed for 360 km/h are fairly quiet at 210. In contrast, the I-95 alignment requires a bridge over the Greenwich Water Club, some residential takings in Cos Cob, and possibly a few commercial takings in Riverside.

Second, it is cheaper. There would need to be some track reconstruction, but no new right-of-way formation, and, most importantly, no new crossing of the Mianus River. The Cos Cob Bridge is in such poor shape that a replacement is most likely necessary even if intercity trains bypass it. The extra cost of the additional aerials, berms, and grade separations in Riverside is perhaps $150-200 million, and that of the second Mianus River crossing would run into many hundreds of millions. This also means somewhat more visual impact, because there would be two bridges over the river rather than just one, and because in parts of Riverside the aerials would be at a higher level than the freeway, which is sunken under the three westernmost overpasses

In either case, one additional investment in Stamford is likely necessary, benefiting both intercity and commuter rail travelers: grade-separating the junction between the New Canaan Branch and the mainline. Without at-grade conflicts between opposing trains on the mainline and the New Canaan Branch, scheduling would be simpler, and trains to and from New Canaan would not need to use the slow interlocking at Stamford station.

The existing route into Stamford already has the potential to be fast. The curves between the Mianus and Stamford station are gentle, and even the S-curve on the approach to Stamford looks like a kilometer in radius, good enough for 180 km/h on a tilting train with proper superelevation.


Between New York and Stamford, the required infrastructure investments for high-speed rail are tame. Everything together except the Mianus crossing should be doable, based on FRA cost items, on a low 9-figure budget.

East of Stamford, the situation is completely different. There are sharp curves periodically, and several in Darien and Norwalk are too tight for high-speed trains. What’s more, I-95 is only available as a straight alternative right-of-way in Norwalk. In Darien, and in Stamford east of the station, there is no easy solution. Everything requires balancing cost, speed, and construction impact.

The one saving grace is that there is much less commuter rail traffic here than between New York and Stamford. With bypasses from Stamford until past Norwalk, only a small number of peak express Metro-North trains east of Greens Farms would ever need to share tracks with intercity trains. Thus the scheduling is at least no longer a problem.

The official plan from NEC Future is to hew to I-95, with all of its curves, and compromise on speed. The curve radius appears to be about 700-750 meters through Stamford and most of Darien, good for about 95 mph over a stretch of 5.5 miles. This is a compromise meant to limit the extent of takings, at the cost of imposing one of the lowest speed limits outside major cities. While the official plan is feasible to construct, the sharp curves suggest that if Amtrak builds high-speed rail in this region, it will attempt a speedup, even at relatively high cost.

There is a possible speedup, involving a minimum curve radius of about 1,700-2,000 meters, good for 235-255 km/h. This would save 70-90 seconds, at similar construction cost to the preferred alignment. The drawback is that it would massively impact Darien, especially Noroton. It would involve carving a new route through Noroton for about a mile. In Stamford, it would require taking an office building or two, depending on precise alignment; in Noroton, the takings would amount to between 55 and 80 houses. The faster option, with 2,000-meter curves, does not necessarily require taking more houses in Noroton: the most difficult curves are farther east. In the picture, this speedup is in white, the preferred alternative is in orange, and the legacy line in teal:

Fortunately, east of Norton Avenue, there is not much commercial and almost no residential development immediately to the north of I-95, making things easier:

The preferred alignment stays to the south of the Turnpike. This is the residential side; even with tight curves, some residential takings are unavoidable, about 20 houses. Going north of I-95 instead requires a few commercial takings, including some auto shops, and one or two small office buildings east of Old Kings Highway, depending on curve radius. Construction costs here are slightly higher, because easing one curve would require elevated construction above I-95, as in one of the Greenwich options above, but this is probably a matter of a few tens of millions of dollars.

The main impact, beyond land acquisition cost, is splitting Noroton in half, at least for pedestrians and cyclists (drivers could drive in underpasses just as they do under highways). Conversely, the area would be close enough to Stamford, with its fast trains to New York, that it may become more desirable. This is especially true for takings within Stamford. However, Darien might benefit as well, near Noroton Heights and Darien stations, where people could take a train to Stamford and change to a high-speed train to New York or other cities.

As in Greenwich, it is a political decision how much a minute of travel time is worth. Darien houses are expensive; at the median price in Noroton, 60-80 houses would be $70-90 million, plus some extra for the office buildings. Against this extra cost, plus possible negative impact on the rest of Noroton, are positive impacts coming from access, and a speedup of 70-90 seconds for all travelers from New York or Stamford to points north.

Norwalk-Greens Farms

In Norwalk, I-95 provides a straight right-of-way for trains. This is the high-speed rail racetrack: for about ten kilometers, until Greens Farms, it may be possible for trains to run at 270-290 km/h.

Here is a photo of Norwalk, with the Walk and Saga Bridges in yellow, a tunnel in the preferred alternative in purple, a possible different alignment in white, and impact zones highlighted:

Three question marks remain about the preferred alignment.

The first question is, which side of the Turnpike to use? The preferred alignment stays on the south side. This limits impact on the north side, which includes some retail where the Turnpike and U.S. 1 are closely parallel, near the Darien/Norwalk boundary; a north side option would have to take it. But the preferred alignment instead slices Oyster Shell Park. A third option is possible, transitioning from the north to the south side just east of the Norwalk River, preparing to rejoin the New Haven Line, which is to the south of I-95 here.

The second question is, why is the transition back to the New Haven Line so complex? The preferred alignment includes a tunnel in an area without any more impacted residences than nearby segments, including in Greenwich and Darien. It also includes a new Saga Bridge, bypassing Westport, with a new viaduct in Downtown Westport, taking some retail and about six houses. An alternative would be to leverage the upcoming Saga Bridge reconstruction, which the RPA plan mentions is relatively easy ($500 million for Saga plus Walk, on the Norwalk River, bypassed by any high-speed alignment), and transition to the legacy alignment somewhat to the west of Westport.

A complicating factor for transitioning west of Westport is that the optimal route, while empty eight years ago, has since gotten a new apartment complex with a few hundred units, marked on the map. Alternatives all involve impact to other places; the options are transitioning north of the complex, taking about twenty units in Westport south of the Turnpike and twenty in Norwalk just north of it.

The third question, related to the second, is, why is Greens Farms so complicated? See photo below:

The area has a prominent S-curve, and some compromises on curve radius are needed. But the preferred alternative doesn’t seem to straighten it. Instead, it builds an interlocking there, with the bypass from Darien and points west. While that particular area has little impact (the preferred alignment transitions in the no man’s land between the New Haven Line and the Turnpike), the area is constrained and the interlocking would be expensive.

No matter what happens, the racetrack ends at Greens Farms. The existing curve seems to have a radius of about a kilometer or slightly more, good for about 190 km/h, and the best that can be done if it is straightened is 1,300-1,400 meters, good for about 200 km/h.

These questions may well have good answers. Unlike in Darien, where all options are bad, in Norwalk and Westport all options are at least understandable. But it’s useful to ask why go south of the Turnpike rather than north, and unless there is a clear-cut answer, both options should be studied in parallel.

Faster-than-Conventional Rail: Where Could It Work?

Note: this post is secretly about Hyperloop and Elon Musk’s most likely fraudulent claim about the Northeast Corridor. But it’s an interesting discussion more in general. Not all such technology is vaporware the way Musk’s efforts are. See more on The Boring Company’s false claims in a piece I published at Urbanize.LA a few days ago.

The upper limit of conventional high-speed rail seems to be 360 km/h. In Japan, experiments at that speed have succeeded, but there already are problems with noise, stopping distance, and catenary wear, and currently trains top at 320; plans to go at 360 depend on a future Shinkansen extension to Sapporo. In China, the maximum speed is 350, with trains capable of reaching 380 but not doing so in practice. In Continental Europe the maximum speed for new lines is 320-330 km/h, whereas in Britain HS2 is designed for about 350 km/h (220 mph).

Faster technologies exist, in service, today. Shanghai’s Transrapid tops at 431 km/h in service, and JR Central’s under-construction maglev line is targeted at 500 km/h, with tests at 600. Vactrains can go even faster, but are still untested technology (and this includes Hyperloop variants). The question is, where is there room for such technology? So far, Siemens’ attempts to sell Transrapid failed beyond the Shanghai airport connector, an orphan 30 km line going from the airport to the edge of the built-up area of the city. JR Central is building the Chuo Shinkansen maglev between Tokyo and Osaka, but so far there are no plans to extend this technology elsewhere – even within Japan, the state is continuing with building Tokyo-Sapporo as conventional Shinkansen rather than maglev.

The Tokyo-Osaka line is somewhat sui generis. JR Central is currently running about 14 trains per hour at the peak on the Tokaido Shinkansen between Tokyo and Shin-Osaka, each with 1,323 seats, and they’re generally full. It is also old – as the first HSR line in the world, it has a curve radius of 2.5 km (newer lines start at 4 km and go up), and a top speed of 270 km/h. This is exactly the sort of situation that favors new technology. The Tokaido Main Line was a popular intercity line in the late 1950s, but Japan National Railways couldn’t add more express trains without bumping against the capacity limit imposed by slower trains using the line; this tilted it in favor of building the Shinkansen. The Paris-Lyon main line was similarly busy in the 1970s, encouraging the construction of the LGV Sud-Est as a bypass. Nowhere in the world except Tokyo-Osaka is there a full conventional HSR line, except Paris-Lyon – but see later why it is a poor candidate for faster technology.

Track sharing

The main tradeoff with maglev, or even faster technology, is cost. This comes from two places. First, higher top speed requires much more advanced civil engineering, with wider curves, which means more tunnels and viaducts. Conventional HSR can limit costs by climbing steeper grades than legacy trains (the LGV Sud-Est has no tunnels, the legacy Paris-Lyon line does). Maglev can climb even faster grades, but once the speed crosses into the vactrain range, the vertical curve radius required to achieve a steep grade is so wide that it is no longer possible to vertically hug terrain the way European HSR lines do.

The second place is the urban approaches. In theory, this should be a strength of faster-than-conventional rail technology, which has a lower minimum curve radius than HSR at equal speed. But in practice, conventional HSR can leverage existing railroad lines on the urban approaches. At lower speed the stopping distances are shorter, so capacity is higher; the upper limit at speed maybe 12-15 trains per hour, but on a low-speed approach it’s closer to 24-30, so it’s possible to share tracks with legacy commuter and intercity trains.

In Japan, Spain, and Taiwan the HSR track gauge is different from the legacy gauge, so track-sharing is not possible in the major cities, driving up the cost of urban approaches. In smaller cities, Japan and Spain have gauge-change technology, which takes too much time to be of use in capacity-constrained big cities but can allow track sharing on branches. But unconventional technology cannot share tracks anywhere, requiring tunnels on urban approaches. The cost of 20 km of urban tunnel can easily match that of 200 km of at-grade greenfield HSR outside urban areas. The Chuo Shinkansen’s cost, around $200 million per km, comes from the fact that 70-80% of the line is underground, in urban areas and under mountains.

This implies that unconventional technology is most useful when there is limited benefit to be gained from track sharing. This includes the following situations:

  1. The cities served do not have usable legacy rail approaches, or else have a surplus of space within which to build a new approach.
  2. There is no need to branch and use legacy track at lower speed.
  3. There is no preexisting high-quality track that HSR can use, either at high speed outside cities or at medium speed on approaches.

In North America, FRA regulations traditionally led to situation #1. But FRA regulations seem to be changing, which makes track-sharing on approaches more feasible; practically every city has approaches with a surplus of passenger rail capacity (yes, even New York – Amtrak runs 4 trains per hour into Penn Station from the west at the peak, it just uses these slots poorly). In Europe, cities with poor approaches are more likely to be served on a branch, since the rest of the network is so strong. Situation #2 never applies here – branching is always useful, letting the LGV Sud-Est carry not just Paris-Lyon trains but also Paris-Marseille, Lille-Lyon, London-Lyon, Paris-Geneva, etc.

Some of the stronger intercity travel markets are in situation #3, but most aren’t. In North America, the Northeast Corridor has long stretches of high-quality track, either already capable of high speed or capable with a small number of curve modifications. That characteristic alone makes it exceptionally bad for unconventional rail technology: such technology would need a new alignment through hundreds of kilometers of suburbia in Massachusetts, Rhode Island, New Jersey, Pennsylvania, and Maryland. Toronto is also a poor candidate for unconventional technology, since it has a long stretch of suburbia in both directions with high-quality four-track commuter rail, straight enough for 200 km/h or even more. Significant suburban tracks are also useful in California (Caltrain, parts of Metrolink) and Chicago. Only the Pacific Northwest, Portland-Seattle-Vancouver, has a real shortage of usable legacy track even on the approaches. So is it a good candidate for unconventional technology? No, for reasons of distance.

The optimal distance

Faster-than-conventional rail is silly at short distance. The difference in travel time is smaller and does not justify the expense. Access and egress times are fixed, and may even go up if the station locations are less central (the Chuo Shinkansen won’t serve Tokyo Station but rather Shinagawa, a few km south of the CBD). So focusing on in-vehicle time is less useful. The Chuo Shinkansen is really at the lowest end of what is acceptable. It works because, again, the Tokaido Shinkansen is at capacity. Tokaido is also relatively circuitous in order to avoid mountains – the distance from Tokyo to Shin-Osaka is 515 km on the Tokaido Shinkansen, 438 on the Chuo Shinkansen, and 405 on a straight line. On the Northeast Corridor, the New York-Washington distance is 362 km on the railroad and 330 on a straight line, a much smaller difference.

Conversely, faster-than-conventional rail is questionable at very long distance. At maglev speed, a New York-Los Angeles train would take perhaps 12 hours, not really competitive with planes for people who don’t mind flying. At vactrain speed, the train would be competitive. However, in either case, trains require linear infrastructure, and repackaging them as a new Hyperloop doesn’t change this basic fact. Ignoring the effects of terrain, a 4,000 km vactrain or maglev line costs ten times as much as a 400 km line. This is not the case for air travel, which requires no fixed infrastructure between the airports.

There should be a good zone in the middle, say the 1,000-1,500 km range. This includes city pairs like Beijing-Shanghai, New York-Chicago, Tokyo-Sapporo, Tokyo-Fukuoka, Delhi-Mumbai, Delhi-Kolkata, and some international European pairs like Paris-Madrid. Going up to 2,000 there are also New York-Miami, Chicago-Dallas-Houston, Beijing-Guangzhou, and Los Angeles-San Francisco-Seattle; in China, where conventional HSR is faster, even 1,000-1,300 km is well within conventional HSR capabilities (Beijing-Shanghai is 1,300).

However, the fact that there is this sweet spot for unconventional rail does not mean that the construction costs are affordable. This remains a question mark. Maglev costs are either in line with HSR costs at equal tunnel proportion, or somewhat higher. The Shanghai maglev cost 10 billion RMB in 2003, which in PPP terms is maybe $100 million per km for an elevated suburban/exurban line (bad, but not terrible), and in exchange rate terms (imported technology) is somewhat more than half that. The Chuo Shinkansen seems to be $200 million per km, 70-80% underground, which is in line with urban tunneling costs in Japan but high by the standards of exurban tunneling (the 60% tunneled extension of the Tohoku Shinkansen to Shin-Aomori was $55 million per km).

The upshot is that a New York-Chicago maglev is likely to cost like 1,200 km of HSR. The western half of this line is easy – maybe a short tunnel in suburban Chicago is required, but there’s so much right-of-way space that an above-ground urban approach should be fine. The eastern half of this line consists of 600 km of pain in the Appalachians, suburban New Jersey, and a new tunnel under the Hudson. Costs approaching $100 billion are likely, and I don’t know that the benefits are commensurate.

Can you start big?

A short maglev or vactrain is of little use. Given the expense of approaches, the best use of expensive infrastructure may well be to build multiple lines using the same approach. For example, not just New York-Chicago or New York-Atlanta-Miami, but both at once, to take advantage of the same maglev tunnel under the Hudson. By itself New York-Chicago might be good enough, but it’s unclear – it’s nowhere the huge benefit/cost ratio coming from a program for conventional HSR on the Northeast Corridor at normal first-world rates.

I think this is the biggest risk with unconventional rail technology. Its basic characteristics suggest that there should be a distance range at which it works well – not too short so as to offer too little benefit versus conventional HSR, not too long so as for construction costs to grind it down. But it’s equally possible that the two bad zones, too short and too long, really overlap, so that 1,200-km lines are still too expensive to compete with planes while not offering enough speed benefit over conventional HSR to justify all this new construction.

The problem, then, is that it’s difficult to start big with a risky technology. The shortest useful maglev segment, Tokyo-Nagoya, is still well over $50 billion, and Tokyo-Osaka approaches $100 billion. This is on a route with proven demand; what about routes that don’t parallel overcrowded conventional HSR? Some government will need to take a $100 billion gamble on a long route hoping that the 1,200-km niche really exists.

I Almost Worked for Hyperloop One

I’d been making cryptic remarks about a possible job offer for a month, and a week ago I tweeted when I heard the final no. I didn’t want to say where I was interviewing until after I heard back, either way; now that I have, I’d like to talk more about the process, and what I think it means for transportation criticism in general.


A few weeks after I posted that I’m transitioning to working in transit or transit writing full-time, a recruiter reached out to me. I wouldn’t have applied myself, not out of ideological opposition to working on Hyperloop, but because until that point, I imagined they wouldn’t have wanted me working there anyway. But once the recruiter emailed me, I started the interview process. It went well. The company was familiar with my criticism of the initial concept and of startups’ own attempts to build it (the last link is Hyperloop One, the one before it is a different company). We talked about the technology, about which models I’d use to evaluate it, about various ways the system could be made more convenient.

People who are familiar with the interview process in the tech industry know that it is long and laborious. There are multiple rounds of interviews, with multiple people involved. Programming jobs involve something called whiteboarding, in which the interviewer will ask the interviewee to solve a coding problem on a whiteboard. I’m not a programmer, unless one counts QBASIC as programming, so I didn’t do any whiteboarding, but the same concept of interview meant there were a lot of hard on-the-spot technical questions. (In contrast, when I interviewed at Frontier, there were hard on-the-spot questions about political and social trends.)

Where I got stuck was American immigration policy. In the US, unlike in normal countries like Canada or Singapore or France, the skilled work visa process is based on a hard cap on the number of visas (called H-1B), rather than on a minimum salary requirement or a labor market analysis to make sure there are more jobs than qualified citizens, both of which criteria are easy to meet in tech. The H-1B cap is too tight – it’s oversubscribed by a factor of about 2; earlier this decade there was political consensus in the US elite that it needed to be lifted, but partisan politicking prevented this from happening. By mid-decade, even before Trump, the consensus frayed, thanks in no small part to anti-immigration reform conservatives, especially Reihan Salam (and, within the urbanist sphere, Aaron Renn). Academia and nonprofit research organizations, such as Frontier (or TransitCenter, or RPA), are exempt from the cap. Tech firms aren’t. This imposes a queue for getting a visa; HR at Hyperloop One said it would be a year, I think it would’ve been a year and a half. It took about a month to figure out whether Hyperloop One could work with me as a remote outside contractor, and when they realized they couldn’t, they had to tell me they couldn’t hire me.

My impressions of Hyperloop’s current status

Elon Musk’s original writeup was a scribble. Very little about it was salvageable. Hyperloop One is more serious. I believe that the most quotable criticism I made of the project in 2013 – the “barf ride” line – is being solved. As I said in 2013, I believe it is not too hard to solve the basic problem of curve radii; the problem is that it makes the civil engineering more expensive, by requiring more tunnels and more viaducts.

We didn’t discuss construction costs at the interview. I think of this as a point in the company’s favor, actually; they’d know that my understanding of construction costs is at too high a level, useful for policymakers but not for actual consultants or contractors. A few months ago, before this process started, I read somewhere that the company says Hyperloop would be 2/3 as expensive as conventional high-speed rail per km, up from Musk’s laughable 1/10 estimate. I’m skeptical about 2/3, but I’m willing to say “I’ll believe it when I see it” and not “yeah, right.”

The capacity constraints coming from the narrow tube diameter are also a problem that I think the company is capable of solving; the cost of a wider tube is higher, but in far less than linear proportion to the extra capacity provided.

There remain two big classes of hitches, one technical and one economic. The technical hitches involve materials engineering that I don’t understand as well, regarding sway inside the tube, ground subsidence, and construction tolerances. I am channeling other critics here; some of them are experts in the field and I am inclined to trust them. I’ve always taken these issues as a black box for conventional HSR and even 500-600 km/h service (maglev or conventional – the TGV reached 574 km/h in an experiment with a special train with a higher power-to-weight ratio), but at higher speeds, they become more serious.

My default assumption is that it’s still solvable at 1000+ km/h, but requires more delicate engineering, which may drive up construction costs even further. Even in my initial writeup I was implicitly arguing the required delicate engineering was such that it was inappropriate to generalize from the costs of oil pipelines, rather than from those of maglev. But it’s possible that the required materials and safety engineering will lead to much higher construction costs, and it’s possible that more basic research is required before it’s viable.

The economic hitch is, what is Hyperloop for? The technology suffers from tension between two opposing forces. The first force is speed: as a very fast technology, Hyperloop is the most useful for long-distance travel. At the distance of Musk’s original Los Angeles-San Francisco idea, security theater and design compromises about station locations (Sylmar and the East Bay, originally) would eat up the entire travel time advantage over conventional HSR. At longer distance, such as New York-Chicago, Hyperloop would still win on time, just as planes beat HSR on time on corridors in the 1,000 km range today. The second force is that Hyperloop still requires linear infrastructure, so it becomes less cost-effective versus planes as the distance increases.

Hyperloop One is a consulting firm. I was asked at the interview about the technology’s applicability in multiple geographies, and gave my opinions (“this place is a good candidate, that place isn’t”). So the company can’t just up and decide on an initial segment, which should probably be a connection from New York (probably in Jersey City or Hoboken) to either South Florida or Chicago. Complicating things, such an initial segment would require many tens of billions of dollars of capital investment, which is not easy for a startup to do. There’s a real problem with using the tech startup model to develop capital-intensive infrastructure, and it’s possible such vactrain technology will always fall between the conventional HSR and airplane chairs. I for one will keep putting vactrains in my 22nd-century science fiction, but not in my near-future science fiction.

On sycophancy

One of the lines I wrote in my initial post is that tech megalomaniacs believe that “people who question [the entrepreneur] and laugh at his outlandish ideas will invariably fail and end up working for him.” I recognize the irony in my almost-working for Hyperloop One.

And yet, I think it offers a valuable lesson about what I variously call sycophancy, or a courtier mentality. I mentioned this about the tech press in the first post; the national political press is less sycophantic (since it can be loyal to an opposition party or political faction, and can draw on the opposition for criticism of current leadership). But local political actors in areas without real political opposition can act like royal courtiers at times, unreasonably praising the leader and begging for scraps. I’ve criticized the RPA for this, for example here: Governor Andrew Cuomo proposed a new airport connector with negative transportation value, and while the area’s transit bloggers all said no, the RPA studied the idea seriously.

The connection with Hyperloop is that I hit the concept pretty hard, and still would’ve been hired but for the US’s broken immigration policy. I don’t know if it’s generalizable to tech. I know it is true in math academia, where if I make a serious criticism of someone’s research program, it’s quite likely we will then write a paper together. For example, my advisor formulated a conjecture he called Dynamical Manin-Mumford; two professors, Rochester’s Tom Tucker and UBC’s Dragos Ghioca, later my own postdoc advisor, found a counterexample, and wrote it up together with my advisor. Nowadays the different researchers in the field are trying to prove different weaker versions of the conjecture that might still be true.

This collaborative aspect is certainly true of transit blogging. I spend a lot of time talking about transit with my biggest critic, who argues my argument about construction costs is spurious and the US is only expensive due to inexperience; I also talk a lot to people who are more nitpickers than critics, like Threestationsquare. I’ve seen the same sentiment at a thinktank whose founder I criticized years ago, and my understanding is that the RPA too is familiar with my writings. But I don’t know if it’s true of government hiring as much – if the MTA, let alone anyone working for Cuomo, is interested in hiring a critic; but then again, MTA hiring has severe problems.

Still, I’d draw a lesson and tell people who write about transportation to be less afraid of being critical. It’s a natural fear; I have it too, when I have criticism for a blogger or Twitter user who I know or consider part of my in-group. But the only result of suppressing criticism is that people who have bad ideas keep promulgating them and either never realize they’re wrong (if they’re honest) or keep acquiring suckers (if they’re dishonest). People who are interested in better transportation recognize this and seek out the critic. Megalomaniacs who are interested in selling themselves suppress and ignore the critic. We know which side Hyperloop One is on; but where is New York’s political system?

The future of my work

I can’t legally work in the US, unless it’s for a cap-exempt institution, which means either a university (that ship sailed five months ago) or a thinktank. Canada is looking unlikely – a consultancy I applied for ended up hiring someone else they felt was more qualified, and Metrolinx isn’t going to hire me. My French is conversational, but not good enough to apply for Keolis’s planning positions here, of which they have plenty, including some I’m otherwise qualified for.

This means I’m going to do transportation writing full-time for the foreseeable future. My plan is to invest in this blog more to make it look nicer (two pieces I’ve recently sent out have decent graphics), and (almost certainly) start a Patreon account in which people who pitch in a few dollars a month can influence what I write about. My intention is to commit to a post every week, not counting personal stuff like this post. I don’t expect this to net me a lot of money, but together with freelancing income, it should be enough to live on in a developed country with universal health care.

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.

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 documents. 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.