# 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.

Curves

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-Greenwich

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.

Riverside-Stamford

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. Stamford-Darien 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 be70-90 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, around200 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.

# 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 perhaps150 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.

# Hyperloop Costs

Two years ago, when Elon Musk first proposed Hyperloop as a faster, cheaper, and more entrepreneurial alternative to California High-Speed Rail, I explained in depth what was wrong with the proposal. The curve radii were too tight for passenger comfort, and any attempt to fix them would require more expensive civil infrastructure. In general, the cost estimates in the plan were laughably low. Musk has moved on, but another team has been trying to build the system. It is planning to build a test track in the next three years, a distance of 8 km, for $150 million. Let us analyze these costs. The per-km cost of this scheme is about$19 million, which if costs don’t run over is reasonable for HSR flat terrain, if anything a bit low. California HSR’s Central Valley segments, in more urbanized areas, are about $24-27 million/km, ex-electrification and systems (which don’t add much). This, in principle, suggests the system could be built for about the same cost as conventional HSR. Of course, it’s already far more expensive than Musk’s original estimate of$6 billion for about 650 km (including tunnels), but it still sounds like a good deal – in theory.

In practice, I’d like to go back to my often-quoted sentence in my post from two years ago, that Hyperloop would be a barf ride. The plan is to run capsules at their full speed, but only when empty. Tests with passengers would be restricted to 160 mph, or about 260 km/h. If the picture in the article describing the test track is accurate, the turn looks like its radius is perhaps 800 meters. Passengers can’t ride through this at very high speed. Even at 260 km/h, it requires full canting, and will make passengers feel noticeable extra gravitational push, about 0.2 g.

The importance of this is that any attempt to build tracks at higher speed will run into problems with both horizontal and vertical curves very quickly. The picture depicts sleek viaducts in empty land; imagine much taller viaducts, to allow the track to curve more gently than the terrain. Once the terrain becomes problematic, as it does on the approaches to the mountain crossings from the Central Valley to both the Los Angeles Basin and the San Francisco Bay Area, costs go up. This is true for any mode of transportation, up to and including mountain roads with hairpin turns, but the higher the speed, the larger the cost differential. In this situation, 4 km horizontal curve radii and 20 km vertical curve radii (about absolute minimum for conventional HSR) are expensive; 20 km horizontal curves and 230 km vertical curves are far more so. And within the urban areas, the inability of the system to leverage legacy rail tracks forces expensive urban viaducts.

# Amtrak Pays More Than Double for High-Speed Trains

Update 2016/8/16: the deal is on, per sources at Amtrak; the cost is $2.5 billion, as reported originally. Update 9/24: as Alex Block notes in comments, sources at Amtrak deny the story, saying that Schumer spoke too soon, and there are still two bidders and Amtrak has not yet made its choice. If the cost turns out to be$1-1.25 billion rather than $2.5 billion, I will withdraw any and all criticism of the procurement process. A press release from Senator Charles Schumer’s office is abuzz: Amtrak chose Alstom’s bid for its next order of high-speed trainsets, the Next-Generation Acelas. The press release mentions the size of the contract,$2.5 billion, and the number of jobs it would create, 750; it did not include any information relevant to passengers, such as the number of trains, the expected schedule of delivery, the expected frequency, and the expected travel time. Various media outlets have reprinted Schumer’s press release without such additional information, or indeed any analysis. Let me rectify this and provide some background as to why this order is a fleece.

The order is for 28 trainsets with 425 seats each. This can be seen here and here. Of those 28 sets, 25 should be available for maximum service, well below the 98% peak availability achieved by the TGV, but an improvement over the Acela’s current 16 trains available out of 20. There is no mention of the number of cars, which is how orders are usually priced. However, on page 30 of the technical specs, it is mentioned that the maximum length is 200 meters, equivalent to 8 cars. The capacity is equivalent to about six cars’ worth of seating at the normal seat density of economy-class HSR (including the Amtrak Regional coach), or about seven cars’ worth averaged over all occupied Acela cars. The RFP mentions half a bistro car with an option for a full car (page 21 of instructions to offerors), so eight cars per train is a reasonable assumption. I have seen references to ten cars per set, which I believe come from the option for two additional cars per train (the instructions phrase this as “an extra 33.33% capacity”). From Schumer’s press release it’s difficult to know whether the $2.5 billion figure is the base order or also the option. Eight cars per train times 28 trains equals 224 cars.$2.5 billion divided by 224 equals $11.2 million per car; if I am wrong and these are ten-car trains, then it is$8.9 million per car. In China, a very high-speed train, capable of 350-380 km/h, costs $4 million per car; this is$900 million at the size of Amtrak’s order. In Europe, the new Eurostar order cost a total of €600-700 million for ten 16-car Velaro trainsets, about $4.7-5.5 million per car in PPP terms (see here and here); the uncertainty comes from euro:pound conversion rates and from the fact that a portion of the order is for refurbishment of the older trainsets. Siemens also sold 8-car Velaros to Deutsche Bahn for$5.2 million per car, again in PPP terms. Japanese trains are even cheaper, about $3 million per car in a recent N700 order, but only last 20 years, whereas European HSR trainsets last 40 and Amtrak specified a 30-year shelf life. The only non-US trainset order that I’ve seen that approaches the$10 million per car mark is the Velaro RUS, which is €600 million for eight 10-car trains, and this includes substantial modifications, such as winterization.

There is no excuse for such high costs. The technical specs are not particularly innovative: on page 22 of the document linked above, it is mentioned that cant deficiency should be 127 mm if the trains don’t tilt and 229 if they do, both of which figures are unimpressive by the respective standards of non-tilting and tilting trains. There is no explicit requirement for tilt. There is a requirement that trains be capable of traveling between New York and Washington in 2:21 (current trip time is 2:48) and between New Haven and Boston in 1:51 (current trip time is about 2 hours, skipping New London, which the specs require trains to stop at); there is no mention of which track upgrades are forthcoming, but given Amtrak’s heavy schedule padding, it is not difficult for a good train to meet the requirements. I do not bring these specs up to attack Amtrak for not demanding more of the trains, but to note that what Amtrak is asking is standard, so there is no reason for trains to be unusually expensive.

I will note that due to Buy America provisions, the trains will be manufactured in the US, at Alstom’s factory in Hornell. This has not caused cost blowouts for the large orders made by the New York subway, the LIRR, and Metro-North, but perhaps this order is small enough that requiring Alstom to build it at a new factory leads to major cost increases. It is also possible that due to difficulties in the bidding process, there are fewer bidders than is normal – Bombardier dropped out of the process last year, and in general, some US contracts have just one bid, with correspondingly elevated prices. But regardless of the reason, Amtrak’s order comes at a factor-of-two cost premium, and Schumer just expressed pride at the few hundred jobs that this waste would create.

# NEC Future: Moving Sideways

The Northeast Corridor high-speed rail investment studies are moving forward, and four days ago the FRA released an early environmental impact study on the subject, as part of the NEC Future program. The study moves in part in the right direction, in that it considers many different segment-level improvements (for example, specific bypasses of curvy segments), but it still isn’t quite going in the right direction. It’s not a bad study in itself, but it does have a lot of drawbacks, and I would like to discuss the ultimate problems with its approach.

Overview

The EIS studies three alternatives, as well as an obligatory No Build option.

Alternative 1 includes minimal investment: capacity improvements already under consideration, including new Hudson tunnels; grade-separation of at-grade rail junctions, including Shell interlocking between the Metro-North New Haven Line to Grand Central and the NEC, which imposes a severe speed limit (30 mph, the worst outside major city stations) and a capacity constraint; and a limited I-95 bypass of the legacy NEC route in eastern Connecticut, to avoid the existing movable bridges. The bulk of the expense under this alternative, excluding the predominantly commuter-oriented new Hudson tunnels, involves replacing or bypassing obsolete or slow bridges with faster segments. I have advocated such an approach in certain cases for years, such as the Cos Cob Bridge; if anything, Alternative 1 does not do this enough, but I do appreciate that it uses this solution.

Alternative 2 constructs HSR along the NEC route, except for a major deviation to serve Hartford. It is also bundled with various bypasses and new stations elsewhere: under this alternative, Philadelphia and Baltimore get new stations, with extensive urban tunneling to reach those stations. Alternative 3 does the same, but considers more deviations, including a tunnel between Long Island and New Haven, and an inland route through Connecticut, closer to I-84 than to I-95 and the legacy NEC; it also constructs dedicated HSR tracks between New York and Washington.

The EIS does not include cost figures. It includes travel time figures on PDF-p. 51, which seem to be based on unfavorable assumptions: Alternative 2, called Run 5, does New York-Boston in 2:17 for trains making a few major-city intermediate stops; the Alternative 3 proposals vary widely depending on alignment, of which the fastest, the I-84 inland route, takes 1:51, again making intermediate stops.

The Good

First, the EIS includes service plan elements, stating the projected frequency of regional and express trains using the tracks. It also talks about clockface scheduling and proposes a pulse in Philadelphia, allowing timed transfers in all directions between local and express intercity trains as well as trains on the Keystone corridor. It goes further and discusses regional rail on the intercity tracks in the alternatives that include extensive new construction. In these ways, it focuses on regionwide rail integration far more than previous plans.

Second, in general, the correct way to think about NEC investment is component by component. The EIS gets closer to this ideal, by considering many different route combinations north of New York, and advancing several of them under the Alternative 3 umbrella.

And third, the concept of Alternative 1 is solid. In many cases, it is possible to bundle a trip time or capacity improvement into the replacement of an obsolete structure at very low additional cost. The example I keep coming back to is the Cos Cob Bridge, but it is equally true of the movable bridges east of New Haven. I also greatly appreciate that Alternative 1 recognizes the importance of grade-separating railroad junctions.

There’s far more interaction between different macro-level alignments, by which I mean such questions as “inland route or coastal route?” and “serve Hartford on the mainline or put it on a branch?”, than between such micro-level investments as individual curve modifications and urban tunnels. This means that instead of discrete alternatives, there should be one umbrella, taking in Alternative 2 and 3 variants, proposing all of those options as possibilities. A future study, with detailed cost figures, could then rank those options in terms of trip time saving per unit of cost, or in terms of social and financial ROI. This way, there would be concrete proposals for what a $5 billion plan, a$10 billion plan, a $20 billion plan, and so on would be. The Ugly Two elements in the study are inexcusable. First, the service plan description explicitly keeps Amtrak’s current separation of premium-fare Regionals and even-more-premium-fare Acelas. This is not how the rest of the world structures HSR: even when the HSR fares are substantially higher than the legacy rail fares, as in Spain, the fare per passenger-km is not very high, and is not targeted exclusively at business travelers. In France, the intercity fare (including TGVs, which are the bulk of French intercity traffic) was on average €0.112 per passenger-km in 2011. Premium service is provided on the same TGVs as standard service, in first-class cars. In contrast, Amtrak charges about$0.29 per passenger-km on the Regional and 0.53 on the Acela. And second, the investment alternatives appear to include more tunneling than is necessary. I will focus on the Hartford-Providence-Boston segment in Alternative 2, since it is less sensitive to assumptions on commuter rail track-sharing than the segments overlapping the New Haven Line. It is possible to go all the way from Hartford to the western margin of the Providence built-up area without any tunneling, and without outrageous bridging; see a past post of mine on the subject here, which concludes that it’s better to just go parallel to I-95 for trip time reasons. In Providence, tunnels are unavoidable, but can still be limited to short segments, mixed with elevated routes along pre-impacted freeway corridors. When I looked at it two years ago, I saw an alignment with just 2 km of tunnel, in Providence itself. In contrast, run A in figure 9 on PDF-p. 56 says that tunnels are about 27% of new construction between Hartford and Boston, which consists of, at a minimum, about 100 km of track between Hartford and Providence. Conclusion The EIS is a step in the right direction, insofar as it does consider issues of integrated service planning and prioritizing construction based on where it can be cheaply bundled into bridge replacement. However, it fails to consider cost limitations, as seen in the excessive tunneling proposed even in areas where high-speed tracks can run entirely above ground. It’s considering more options, which is good, but, Alternative 1, while representing a golden concept, is not sufficiently developed. What I would like to see from a study in this direction is a mixture of the following: • Discussion of how to avoid tunnels, including various tradeoffs that have to be made (for example, above-ground construction may require more takings). Generally, I want to see much less tunneling than is currently proposed. • A well-developed incremental option, similar to Alternative 1 but more extensive, including for example I-95 bypasses all the way from New Haven to Kingston and along strategic segments of the New Haven Line, such as in Port Chester and Greenwich. • Greater integration with regional rail; one litmus test is whether the Providence Line is proposed to be three-tracked for long stretches, or four-tracked at a key bypass station (the options are Sharon and the Route 128-Readville segment), and another is discussion of high-acceleration electric multiple units on the Providence Line and the Penn Line. • Unbundling of projects within each alignment – there is no need to, for example, consider the Philadelphia and Baltimore tunnels together (I also think neither is a good idea, but that’s a separate discussion). The view should be toward an optimal set of projects within each alignment, since macro-level decisions such as whether to serve Hartford are more political than micro-level ones of which curves to fix. This permits explicit discussions such as “would you be willing to spend2 billion and slow through-trains by 9 minutes to serve Hartford?”.
Except for the first, all are kind of present in this study, but in insufficient amount for me to view it as truly a step forward. The ultimate goal must be HSR in the Northeast on a reasonable budget – closer to $10 or even$20 billion than to the Amtrak Vision’s proposed \$150 billion – and this requires carefully looking at which scope is required and which is not. The EIS has elements that can be used toward that goal, but ultimately it is a step sideways, not forward or in the wrong direction.