Category: Regional Rail

The Nine-Euro Ticket

A three-month experiment has just ended: the 9€ monthly, valid on all local and regional public transport in Germany. The results are sufficiently inconclusive that nobody is certain whether they want it extended or not. September monthlies are reverting to normal fares, but some states (including Berlin and Brandenburg) are talking about restoring something like it starting October, and Finance and Transport Ministers Christian Lindner and Volker Wissing (both FDP) are discussing a higher-price version on the same principle of one monthly valid nationwide.

The intent of the nine-euro ticket

The 9€ ticket was a public subsidy designed to reduce the burden of high fuel prices – along with a large three-month cut in the fuel tax, which is replaced by a more permanent cut in the VAT on fuel from 19% to 7%. Germany has 2.9% unemployment as of July and 7.9% inflation as of August, with core inflation (excluding energy and food) at 3.4%, lower but still well above the long-term target. It does not need to stimulate demand.

Moreover, with Russia living off of energy exports, Germany does not need to be subsidizing energy consumption. It needs to suppress consumption, and a few places like Hanover are already restricting heating this winter to 19 degrees and no higher. The 9€ ticket has had multiple effects: higher use of rail, more domestic tourism, and mode shift – but because Germany does not need fiscal stimulus right now and does need to suppress fuel consumption, the policy needs to be evaluated purely on the basis of mode shift. Has it done so?

The impact of the nine-euro ticket on modal split

The excellent transport blog Zukunft Mobilität aggregated some studies in late July. Not all reported results of changes in behavior. One that did comes from Munich, where, during the June-early July period, car traffic fell 3%. This is not the effect of the 9€ ticket net of the reduction in fuel taxes – market prices for fuel rose through this period, so the reduction in fuel taxes was little felt by the consumer. This is just the effect of more-or-less free mass transit. Is it worth it?

Farebox recovery and some elasticities

In 2017 and 2018, public transport in Germany had a combined annual expenditure of about 14 billion €, of which a little more than half came from fare revenue (source, table 45 on p. 36). In the long run, maintaining the 9€ ticket would thus involve spending around 7 billion € in additional annual subsidy, rising over time as ridership grows due to induced demand and not just modal shift. The question is what the alternative is – that is, what else the federal government and the Länder can spent 7 billion € on when it comes to better public transport operations.

Well, one thing they can do is increase service. That requires us to figure out how much service growth can be had for a given increase in subsidy, and what it would do to the system. This in turn requires looking at service elasticity estimates. As a note of caution, the apparent increase in public transport ridership over the three months of more or less free service has been a lot less than what one would predict from past elasticity estimates, which suggests that at least fare elasticity is capped – demand is not actually infinite at zero fares. Service elasticities are uncertain for another reason: they mostly measure frequency, and frequency too has a capped impact – ridership is not infinite if service arrives every zero minutes. Best we can do is look at different elasticity estimates for different regimes of preexisting frequency; in the highest-frequency bucket (every 10 minutes or better), which category includes most urban rail in Germany, it is around 0.4 per the review of Totten-Levinson and their own work in Minneapolis. If it’s purely proportional, then doubling the subsidy means increasing service by 60% and ridership by 20%.

The situation is more complicated than a purely proportional story, though, and this can work in favor of expanding service. Just increasing service does not mean doubling Berlin U-Bahn frequency from every 5 to every 2.5 minutes; that would achieve very little. Instead, it would bump up midday service on the few German rail services with less midday than peak frequency, upgrade hourly regional lines to half-hourly (in which case the elasticity is not 0.4 but about 1), add minor capital work to improve speed and reliability, and add minor capital work to save long-term operating costs (for example, by replacing busy buses with streetcars and automating U-Bahns).

The other issue is that short- and long-term elasticities differ – and long-term elasticities are higher for both fares (more negative) and service (more positive). In general, ridership grows more from service increase than from fare cutting in the short and long run, but it grows more in the long run in both cases.

The issue of investment

The bigger reason to end the 9€ ticket experiment and instead improve service is the interaction with investment. Higher investment levels call for more service – there’s no point in building new S-Bahn tunnels if there’s no service through them. The same effect with fares is more muted. All urban public transport agencies project ridership growth, and population growth is largely urban and transit-oriented suburban.

An extra 7 billion € a year in investment would go a long way, even if divided out with direct operating costs for service increase. It’s around 250 km of tramway, or 50 km of U-Bahn – and at least the Berlin U-Bahn (I think also the others) operationally breaks even so once built it’s free money. In Berlin a pro-rated share – 300 million €/year – would be a noticeable addition to the city’s 2035 rail plan. Investment also has the habit to stick in the long term once built, which is especially good if the point is not to suppress short-term car traffic or to provide short-term fiscal stimulus to a 3% unemployment economy but to engage in long-term economic investment.

Penn Station Expansion is Based on Fraud

New York is asking for $20 billion for reconstruction ($7 billion) and physical expansion ($13 billion) of Penn Station. The state is treating it as a foregone conclusion that it will happen and it will get other people’s money for it; the state oversight board just voted for it despite the uncertain funding. Facing criticism from technical advocates who have proposed alternatives that can use Penn Station’s existing infrastructure, lead agency Empire State Development (ESD) has pushed back. The document I’ve been looking at lately is not new – it’s a presentation from May 2021 – but the discussion I’ve seen of it is. The bad news is that the presentation makes fraudulent claims about the capabilities of railroads in defense of its intention to waste $20 billion, to the point that people should lose their jobs and until they do federal funding for New York projects should be stingier. The good news is that this means that there are no significant technical barriers to commuter rail modernization in New York – the obstacles cited in the presentation are completely trivial, and thus, if billions of dollars are available for rail capital expansion in New York, they can go to more useful priorities like IBX.

What’s the issue with Penn Station expansion?

Penn Station is a mess at both the concourse and track levels. The worst capacity bottleneck is the western approach across the river, the two-track North River Tunnels, which on the eve of corona ran about 20 overfull commuter trains and four intercity trains into New York at the peak hour; the canceled ARC project and the ongoing Gateway project both intend to address this by adding two more tracks to Penn Station.

Unfortunately, there is a widespread belief that Penn Station’s 21 existing tracks cannot accommodate all traffic from both east (with four existing East River Tunnel tracks) and west if new Hudson tunnels are built. This belief goes back at least to the original ARC plans from 20 years ago: all plans involved some further expansion, including Alt G (onward connection to Grand Central), Alt S (onward connection to Sunnyside via two new East River tunnel tracks), and Alt P (deep cavern under Penn Station with more tracks). Gateway has always assumed the same, calling for a near-surface variation of Alt P: instead of a deep cavern, the block south of Penn Station, so-called Block 780, is to be demolished and dug up for additional tracks.

The impetus for rebuilding Penn Station is a combination of a false belief that it is a capacity bottleneck (it isn’t, only the Hudson tunnels are) and a historical grudge over the demolition of the old Beaux-Arts station with a labyrinthine, low-ceiling structure that nobody likes. The result is that much of the discourse about the need to rebuild the station is looking for technical justification for an aesthetic decision; unfortunately, nobody I have talked to or read in New York seems especially interested in the wayfinding aspects of the poor design of the existing station, which are real and do act as a drag on casual travel.

I highlight the history of Penn Station and the lead agency – ESD rather than the MTA, Port Authority, or Amtrak – because it showcases how this is not really a transit project. It’s not even a bad transit project the way ARC Alt P was or the way Gateway with Block 780 demolition is. It’s an urban renewal project, run by people who judge train stations by which starchitect built them and how they look in renderings rather than by how useful they are for passengers. Expansion in this context is about creating the maximum footprint for renderings, and not about solving a transportation problem.

Why is it believed that Penn Station needs more tracks?

Penn Station tracks are used inefficiently. The ESD pushback even hints at why, it just treats bad practices as immutable. Trains have very long dwell times: per p. 22 of the presentation, the LIRR can get in and out in a quick 6 minutes, but New Jersey Transit averages 12 and Amtrak averages 22. The reasons given for Amtrak’s long dwell are “baggage” (there is no checked baggage on most trains), “commissary” (the cafe car is restocked there, hardly the best use of space), and “boarding from one escalator” (this is unnecessary and in fact seasoned travelers know to go to a different concourse and board there). A more reasonable dwell time at a station as busy as Penn Station on trains designed for fast access and egress is 1-2 minutes, which happens hundreds of times a day at Shin-Osaka; on the worse-designed Amtrak rolling stock, with its narrower doors, 5 minutes should suffice.

New Jersey Transit can likewise deboard fast, although it might need to throw away the bilevels and replace them with longer single-deck trains. This reduces on-board capacity somewhat, but this entire discussion assumes the Gateway tunnel has been built, otherwise even present operations do not exhaust the station’s capacity. Moreover, trains can be procured for comfortable standing; subway riders sometimes have to stand for 20-30 minutes and commuter rail riders should have similar levels of comfort – the problem today is standees on New Jersey Transit trains designed without any comfortable standing space.

But by far the biggest single efficiency improvement that can be done at Penn Station is through-running. If trains don’t have to turn back or even continue to a yard out of service, but instead run onward to suburbs on the other side of Manhattan, then the dwell time can be far less than 6 minutes and then there is much more space at the station than it would ever need. The station’s 21 tracks would be a large surplus; some could be removed to widen the platform, and the ESD presentation does look at one way to do this, which isn’t necessarily the optimal way (it considers paving over every other track to widen the platforms and permit trains to open doors on both sides rather than paving over every other track pair to widen the platforms much more but without the both-side doors). But then the presentation defrauds the public on the opportunity to do so.

Fraudulent claim #1: 8 minute dwells

On p. 44, the presentation compares the capacity with and without through-running, assuming half the tracks are paved over to widen the platforms. The explicit assumption is that through-running commuter rail requires trains to dwell 8 minutes at Penn Station to fully unload and load passengers. There are three options: the people who wrote this may have lied, or they may be incompetent, or they be both liars and incompetent.

In reality, even very busy stations unload and load passengers in 30-60 seconds at rush hour. Limiting cases reaching up to 90-120 seconds exist but are rare; the RER A, which runs bilevels, is the only one I know of at 105.

On pp. 52-53, the presentation even shows a map of the central sections of the RER, with the central stations (Gare du Nord, Les Halles, and Auber/Saint-Lazare) circled. There is no text, but I presume that this is intended to mean that there are two CBD stations on each line rather than just one, which helps distribute the passenger load better; in contrast, New York would only have one Manhattan station on through-trains on the Northeast Corridor, which requires a longer dwell time. I’ve heard this criticism over the years from official and advocate sources, and I’m sympathetic.

What I’m not sympathetic to is the claim that the dwell time required at Penn Station is more than the dwell time required at multiple city center stations, all combined. On the single-deck RER B, the combined rush hour dwell time at Gare du Nord and Les Halles is around 2 minutes normally (and the next station over, Saint-Michel, has 40-60 second rush hour dwells and is not in the CBD unless you’re an academic or a tourist); in unusual circumstances it might go as high as 4 minutes. The RER A’s combined dwell is within the same range. In Munich, there are six stations on the S-Bahn trunk between Hauptbahnhof and Ostbahnhof – but at the intermediate stations (with both-sides door opening) the dwell times are 30 seconds each and sometimes the doors only stay open 20 seconds; Hauptbahnhof and Ostbahnhof have longer dwell times but are not busier, they just are used as control points for scheduling.

The RER A’s ridership in 2011 was 1.14 million trips per weekday (source, p. 22) and traffic was 30 peak trains per hour and 24 reverse-peak trains; at the time, dwell times at Les Halles and Auber were lower than today, and it took several more years of ridership growth for dwell times to rise to 105 seconds, reducing peak traffic to 27 and then 24 tph. The RER B’s ridership was 983,000 per workday in 2019, with 20 tph per direction. Munich is a smaller city, small enough New Yorkers may look down on it, but its single-line S-Bahn had 950,000 trips per workday in 2019, on 30 peak tph in each direction. In contrast, pre-corona weekday ridership was 290,000 on the LIRR, 260,000 on Metro-North, and around 270,000 on New Jersey Transit – and the LIRR has a four-track tunnel into Manhattan, driving up traffic to 37 tph in addition to New Jersey’s 21. It’s absurd that the assumption on dwell time at one station is that it must be twice the combined dwell times at all city center stations on commuter lines that are more than twice as busy per train as the two commuter railroads serving Penn Station.

Using a more reasonable figure of 2 minutes in dwell time per train, the capacity of through-running rises to a multiple of what ESD claims, and through-running is a strong alternative to current plans.

Fraudulent claim #2: no 2.5% grades allowed

On pp. 38-39, the presentation claims that tracks 1-4 of Penn Station, which are currently stub-end tracks, cannot support through-running. In describing present-day operations, it’s correct that through-running must use the tracks 5-16, with access to the southern East River Tunnel pair. But it’s a dangerously false assumption for future infrastructure construction, with implications for the future of Gateway.

The rub is that the ARC alternatives that would have continued past Penn Station – Alts P and G – both were to extend the tunnel east from tracks 1-4, beneath 31st Street (the existing East River Tunnels feed 32nd and 33rd). Early Gateway plans by Amtrak called for an Alt G-style extension to Grand Central, with intercity trains calling at both stations. There was always a question about how such a tunnel would weave between subway tunnels, and those were informally said to doom Alt G. The presentation unambiguously answers this question – but the answer it gives is the exact opposite of what its supporting material says.

The graphic on p. 39 shows that to clear the subway’s Sixth Avenue Line, the trains must descend a 2.45% grade. This accords with what I was told by Foster Nichols, currently a senior WSP consultant but previously the planner who expanded Penn Station’s lower concourse in the 1990s to add platform access points and improve LIRR circulation, thereby shortening LIRR dwell times. Nichols did not give the precise figure of 2.45%, but did say that in the 1900s the station had been built with a proviso for tracks under 31st, but then the subway under Sixth Avenue partly obstructed them, and extension would require using a grade greater than 2%.

The rub is that modern urban and suburban trains climb 4% grades with no difficulty. The subway’s steepest grade, climbing out of the Steinway Tunnel, is 4.5%, and 3-3.5% grades are routine. The tractive effort required can be translated to units of acceleration: up a 4% grade, fighting gravity corresponds to 0.4 m/s^2 acceleration, whereas modern trains do 1-1.3 m/s^2. But it’s actually easier than this – the gradient slopes down when heading out of the station, and this makes the grade desirable: in fact, the subway was built with stations at the top of 2.5-3% grades (for example, see figure 7 here) so that gravity would assist acceleration and deceleration.

The reason the railroaders don’t like grades steeper than 2% is that they like the possibility of using obsolete trains, pulled by electric locomotives with only enough tractive effort to accelerate at about 0.4 m/s^2. With such anemic power, steeper grades may cause the train to stall in the tunnel. The solution is to cease using such outdated technology. Instead, all trains should be self-propelled electric multiple units (EMUs), like the vast majority of LIRR and Metro-North rolling stock and every subway train in the world. Japan no longer uses electric locomotives at all on its day trains, and among the workhorse European S-Bahn systems, all use EMUs exclusively, with the exception of Zurich, which still has some locomotive-pulled trains but is transitioning to EMUs.

It costs money to replace locomotive-hauled trains with EMUs. But it doesn’t cost a lot of money. Gateway won’t be completed tomorrow; any replacement of locomotives with EMUs on the normal replacement cycle saves capital costs rather than increasing them, and the same is true of changing future orders to accommodate peak service expansion for Gateway. Prematurely retiring locomotives does cost money, but New Jersey Transit only has 100 electric locomotives and 29 of them are 20 years old at this point; the total cost of such an early retirement program would be, to first order, about $1 billion. $1 billion is money, but it has independent transportation benefits including faster acceleration and higher reliability, whereas the $13 billion for Penn Station expansion have no transportation benefits whatsoever. Switzerland may be a laggard in replacing the S-Bahn’s locomotives with EMUs, but it’s a leader in the planning maxim electronics before concrete, and when the choice is between building a through-running tunnel for EMUs and building a massive underground station to store electric locomotives, the correct choice is to go with the EMUs.

How do they get away with this?

ESD is defrauding the public. The people who signed their names to the presentation should most likely not work for the state or any of its contractors; the state needs honest, competent people with experience building effective mass transit projects.

Those people walk around with their senior manager titles and decades of experience building infrastructure at outrageous cost and think they are experts. And why wouldn’t they? They do not respect any knowledge generated outside the New York (occasionally rest-of-US) bubble. They think of Spain as a place to vacation, not as a place that built 150 kilometers of subway 20 years ago for the same approximate cost as Second Avenue Subway phases 1 and 2. They think of smaller cities like Milan as beneath their dignity to learn about.

And what’s more, they’ve internalized a culture of revealing as little as possible. That closed attitude has always been there; it’s by accident that they committed two glaring acts of fraud to paper with this presentation. Usually they speak in generalities: the number of people who use the expression “apples-to-apples” and provide no further detail is staggering. They’ve learned to be opaque – to say little and do little. Most likely, they’re under political pressure to make the Penn Station reconstruction and expansion look good in order to generate what the governor thinks are good headlines, and they’ve internalized the idea that they should make up numbers to justify a political project (and in both the Transit Costs Project and previous reporting I’d talked to people in consulting who said they were under such formal or informal pressure for other US projects).

The way forward

With too much political support for wasting $20 billion at the state level, the federal government should step in and put an end to this. The Bipartisan Infrastructure Law (BIL) has $66 billion for mainline rail; none of this money should go to Penn Station expansion, and the only way any money should go to renovation is if it’s part of a program for concrete improvement in passenger rail function. If New York wishes to completely remodel the platform level, and not just pave over every other track or every other track pair, then federal support should be forthcoming, albeit not for $7 billion or even half that. But it’s not a federal infrastructure priority to restore some kind of social memory of the old Penn Station. Form follows function; beautiful, airy train stations that people like to travel through have been built under this maxim, for example Berlin Hauptbahnhof.

To support good rail construction, it’s obligatory that experts be put in charge – and there aren’t any among the usual suspects in New York (or elsewhere in the US). Americans respect Germany more than they do Spain but still less than they should either; unless they have worked in Europe for years, their experience at Berlin Hbf and other modern stations is purely as tourists. The most celebrated New York public transportation appointment in recent memory, Andy Byford, is an expert (on operations) hired from abroad; as I implored the state last year, it should hire people like him to head major efforts like this and back them up when they suggest counterintuitive things.

Mainline rail is especially backward in New York – in contrast, the subway planners that I’ve had the fortune to interact with over the years are insightful and aware of good practices. Managers don’t need much political pressure to say absurd things about gradients and dwell times, in effect saying things are impossible that happen thousands of times a day on this side of the Pond. The political pressure turns people who like pure status quo into people who like pure status quo but with $20 billion in extra funding for a shinier train hall. But both the political appointees and the obstructive senior managers need to go, and managers below them need to understand that do-nothing behavior doesn’t get them rewarded and (as they accumulate seniority) promoted but replaced. And this needs to start with a federal line in the sand: BIL money goes to useful improvements to speed, reliability, capacity, convenience, and clarity – but not to a $20 billion Penn Station reconstruction and expansion that do nothing to address any of these concerns.

In-Motion Charging is not for Trains

Streetsblog Massachusetts editor Christian MilNeil has just asked a very delicate question on Twitter about battery power for public transportation. In-motion charging (IMC) is a positive technological development for buses, wiring part of a route in order to provide electric coverage to a much broader area. So why not use it for trains? The context is that the government of Massachusetts is doing everything in its power to avoid wiring commuter rail; its latest excuse is that a partly-wired system with battery-electric trains is cheaper. So how come IMC works for buses but not trains?

The answer is that trains and buses differ in ways that make fully wiring a train much more advantageous for equipment cost while costing less compared with IMC-style partial wiring – and the size of trains makes the equipment cost much more prominent.

Equipment cost

The cost of a single-deck electric multiple unit (EMU) other than high-speed rail is about $100,000 per linear meter of length, and appears to have changed little over the last 10-20 years. I have a list of recent tramways built in Europe for that cost, a shorter one of subways (including more outliers due to procurement problems or bespoke designs), and some standard citations for commuter rail EMUs. For the latter, here is a recent example of a Coradia Continental order in Germany: 200M€ for 32 trainsets, 20 with five 18-meter cars and 12 with four, or 75,000€ per linear meter.

In contrast, battery-EMUs (BEMUs) are far more expensive. Comparing like with like, here is a recent Coradia Continental BEMU order for Leipzig-Chemnitz, which line should have long been wired: 100M€ for 11 three-car, 56-meter long trainsets, or 160,000€ per linear meter.

Buses do not display such a premium. Trolleybus advocate Martin Wright writes a comparison of battery-electric and trolleybuses for Vancouver, and suggests that equipment costs are largely the same in the North American market (which is expensive by European standards). TU Berlin’s Dominic Jefferies and Dietmar Göhlich find that the base cost of an electric 12-meter bus is 450,000€, rising to 600,000€ with battery (p. 25); this is a premium, but it’s small, almost an order of magnitude less than that for trains per unit of length. Kiepe says that the cost of rebuilding 16 12-meter trolleybuses with IMC for Solingen is in the single-digit millions.

Why?

How come trains display such a large premium for batteries over electric traction supplied by trackside distribution (catenary wire or third rail) and buses don’t? This is not about the cost of the batteries: Jeffries-Göhlich cite a cost of 500-800€/kWh for a battery pack on a bus, and while Alstom hasn’t said what the battery capacity of the Coradia is in kWh, based on the range (120 km) and this slide deck about BEMUs (or PDF-p. 22 of a VDE study about EMUs and BEMUs), the capacity is likely around 700 kWh for the entire three-car train, with a cost about an order of magnitude less than the observed cost premium over EMUs.

Rather, the issue is likely about fitting the batteries on the train. Railvolution reports that to fit the batteries, Alstom had to demotorize one of the three powered bogies, reducing the maximum power drawn from 2.16 MW to 1.44. As a byproduct, this also somewhat hurts performance, increasing the stop penalty from the train’s maximum speed of 160 km/h by 15-20 seconds (46 empty or 51 full for an EMU, 60 and 71 respectively for a BEMU).

The cost of wiring

The cost of trolleybus wiring, at least judging by industry brochures such as that of UITP, is linear in route-km. This makes IMC attractive in that it cuts said cost by a factor of 2 to 3 on a single route, or even more on a route that branches out of a common trunk. For this reason, IMC is ideally suited for branched bus networks such as that of Boston, and is less valuable on grids where it’s uncommon for multiple bus routes to run together for a significant portion, such as the systems in Chicago, Toronto, and Vancouver.

But rail electrification does not quite work this way. Overall, the cost of wiring is mostly proportional to route-length, but the cost appears to be split evenly between the wire and the substations. A full-size commuter train in a major metropolitan area like Boston would be drawing around 7 MW while accelerating; a Citaro bus has a 220 kW diesel engine, or 125 in the electric version. Even taking into account that buses are slower and more frequent than trains and thus run at much higher frequency per route-km, there’s nearly a full order of magnitude between the substation costs per km for the two modes.

The upshot is that while IMC saves the cost of installing wire, it does not save a single penny on the cost of installing substations. The substations still need to fully charge a train in motion – and derating the train’s power as Alstom did does not even help much, it just means that the same amount of energy is applied over a longer period while accelerating but then still needs to be recharged on the wire.

How benefits of electrification scale

Electrification has a number of benefits over diesel power:

  • No local air pollution
  • Much less noise, and none while idling
  • Higher reliability
  • Higher performance
  • Much lower lifecycle costs

The first three are shared between externally-supplied electric and battery-electric power, at least when there’s IMC (pure battery power is unreliable in cold weather). The fourth is a mix: BEMUs have better performance than DMUs but worse than EMUs – whereas with buses this flips, as trolleybuses have performance constraints at trolleywire junctions. The fifth is entirely an EMU benefit, because of the high cost of BEMU acquisition.

The first two benefits are also much more prominent for buses than for trains. Buses run on streets; the pollution affects nearby pedestrians and residents as well as waiting riders, and the idling noise is a nuisance at every intersection and whenever there’s car traffic. Bus depots are an air quality hazard, leading to much environmental justice activism about why they’re located where they are. Trains are more separated from the public except when people wait for them.

In contrast, the last benefit, concerning lifecycle costs, is more prominent on trains. The benefits of electrification scale with the extent of service; that the acquisition cost of EMUs is around half that of BEMUs, and the lifecycle cost is around half that of DMUs, means that the return on investment on electrification can be modeled as a linear function of the fleet size in maximum service.

A US-standard 25 meter railcar costs $2.5 million at global EMU prices (which the US was recently able to achieve, though not anymore), and twice that at BEMU prices. 40-year depreciation and 4% interest are $162,500/year; a single train per hour, per car, is around $3,000/km (this assumes 50-60 km/h average speed counting turnaround time), or $6,000 counting both directions, and lifecycle maintenance costs appear to be similar to initial acquisition cost, for a total of around $12,000/km. At $2.5 million/km, this means electrification has an ROI of 0.5% per peak car per hour; a single 8-car train per hour is already enough for 4% ROI.

The numbers don’t work out this way for buses. Workhorse city buses run every 5 minutes at rush hour, and may occasionally run articulated buses, but the capacity is still only equivalent to a single hourly train; in the absence of IMC, electrification of buses is therefore hard to justify without the additional environmental benefits. But those environmental benefits can be provided at much lower cost with IMC.

Why electrify?

The upshot of the above discussion is that the reasons to electrify buses and trains are not the same. Bus electrification benefits center environmental and environmental justice: diesel buses are noisy and polluting and have poor ride quality. The only reason to wire buses at all rather than go for unwired battery-electric buses (BEBs) is that BEBs are not reliable in freezing temperatures and cost far more than diesels due to their downtime for charging.

But rail electrification is different. The environmental benefits are real, but less important. Train depots have not been major sources of air pollution since the steam era, unlike bus depots. The primary reasons are technical: equipment acquisition costs, maintenance costs, performance, reliability. And those overall advantage EMUs over BEMUs with IMC.

Suburban Metros and S-Bahns

Liam O’Connell just wrote a deep dive into the history of PATH in the 1970s. I recommend people read it; as the unprofitable Hudson and Manhattan (H&M) system was transferred to Port Authority’s control, to be subsidized via the toll revenue from the Hudson bridges that had killed ridership starting in the 1930s, there were plans for expansion deep into suburbia, as far out as Plainfield. The expansion was a twofer: the H&M was unprofitable and needed change, and the same was true of mainline rail in the Northeast. Liam goes over the history of the proposal to expand service to Plainfield, and calls it an S-Bahn, comparing it to existing American examples of suburban metro like BART as well as to actual S-Bahn-type systems like the German ones bearing the name but also the Paris RER and the Tokyo subway.

In reality, there is a distinction between suburban metro service and S-Bahn service. Liam gets at one of the issues that derailed the Plainfield extension (it attempted to use high-cost capital expansion to paper over operational problems). But the distinction goes far deeper than that, and applies even to suburban metro services with a fraction of the operating costs of PATH, like BART. These are not S-Bahns, and understanding how they differ is critical.

The basic difference is that S-Bahns run on mainline rail tracks; suburban metros do not. This distinction has implications for capital planning, urban network shape, and urban growth planning. In reality it’s more complicated than that, but instead of drawing a sharp boundary, it’s better to begin by going over the core features of each of the two service types (in linguistics this is called prototypes).

S-Bahn

The core feature of an S-Bahn is that it runs on mainline track and combines urban and suburban rail service. Every S-Bahn service I know of that bears that name or is otherwise associated with the core of the model shares track with other mainline services, but the busier ones (Berlin, Paris, Tokyo) do it only peripherally, because core lines are limited by track capacity.

The reason to use mainline track is that it’s already there, cutting construction costs. In most cases it also fits into a growth plan around existing town centers, such as the Finger Plan. Cities that build S-Bahn systems often have a surplus of industrial track serving declining manufacturing uses that can be redeveloped, for example the goods yards of historic rail terminals in European cities.

With a surplus of mainline track to use, S-Bahn systems employ extensive branching. There are more branches in the suburbs than urban trunk lines to feed them, so the system maximizes use of existing track this way. Conversely, the urban trunk lines need very high frequency to be usable as urban rail whereas the suburban branches can make do with a train every 10-20 minutes, so the branching structure generally matches frequency to both demand and passenger convenience.

Suburban metro

It is sometimes desirable to extend a metro system isolated from the mainline rail network into the suburbs. This is most commonly done when there are too few mainlines for adequate suburban service; China makes extensive use of suburban metro lines, and the commuter lines it does have are not run to S-Bahn standards (for example, the Beijing Suburban Railway is infrequent). Seoul, whose first subway line is an S-Bahn, employs greenfield suburban metros extensively as well, for example the Shin-Bundang Line.

Without an extensive system of existing lines to tap into, suburban metros necessarily cost more than S-Bahns. This means that there are fewer lines, so each line or branch has to be shorter, more frequent, and more intensively developed. Stockholm provides a ready-made example: it did not build an urban S-Bahn like the Copenhagen S-Tog, and instead built the three-line T-bana to a range of 10-20 km out of city center, with Million Program projects centered on T-bana stations.

In reality, it’s common for S-Bahn systems to also build greenfield suburban lines. For example, the RER A’s Marne-la-Vallée branch is greenfield, and does not look too different from the lines inherited from mainline rail; but it’s embedded in a mainline-compatible system, running through to legacy track on the other side of the city.

American postwar suburban rapid transit

American cities extending their urban rail networks into the suburbs ended up building suburban metros: they were never integrated with mainline rail. BART even runs on a different track gauge from the mainline network. Many of the other systems run alongside legacy lines instead of on them, at high cost. The high costs meant that there were fewer lines – the Washington Metro has complex interlining for a three-line metro, but by S-Bahn standards, it’s poor in branches.

Some of these systems had older metros to integrate with, including the Rockaways extension of the A in New York and the Green Line D Branch and the Red Line to Braintree in Boston; all three were taken over from disused commuter rail. The Braintree extension is notable in that the Old Colony Lines go much further than Braintree, but the conversion costs meant there would be no subway extension into suburbia past Braintree, and more recently the region awkwardly reopened the Old Colony Lines as low-frequency diesel commuter rail, with parts of the right-of-way encroached by the subway.

The PATH extension was to cost $402 million in 1975, or $2.2 billion today, about $80 million/km for an above-ground system that could run entirely on existing track. Newark-Elizabeth, on the Northeast Corridor, had plenty of spare capacity then and still does now – only after Gateway opens does the section need additional tracks, and parts of it are already six-track. Relative to what was required, the construction cost was extremely high. The projected two-way ridership was 28,200/day, or $78,000/rider, in an economy with less than half the average income of today.

The failure of postwar American rapid transit

Liam’s post mentions BART in the same sentence as the RER or the Tokyo subway system. This is a provocation, and Liam knows this. BART’s annual ridership before corona was not much higher than just the total number of boardings and alightings at Gare du Nord. The Bay Area’s modal split is comparable to that of provincial French metro areas like Marseille and Toulouse, with an urban light metro or light rail system and thoroughly auto-oriented character outside the historic core. So what gives?

This isn’t quite a shortcoming of the suburban metro model. Stockholm uses it, and so does all of China. Rather, it’s a combination of several problems.

  1. The suburban metro model requires extensive transit-oriented development to compensate for the narrower reach of the system. Stockholm built Vällingby and countless other suburbs on top of the T-bana. Washington built a handful of TOD centers like Arlington and Bethesda, and the other American examples built nothing, preferring parking lots and garages at stations.
  2. American construction costs were too high even then. The cost of the proposed PATH extension was $2.2 billion for 27 km on existing above-ground right-of-way. The actually-built Washington Metro cost $9.3 billion in current dollars by 2001, around $25 billion in today’s money, for a 166 km system of which 72 are underground. In contrast, the T-bana cost, in today’s PPP money, around $3.6 billion for 104 km of which 57 are underground, around one fifth the per-km cost of WMATA. As a result, not much was built, and in many cases what has been built follows freeway medians to economize, leading to further ridership shortfalls.
  3. BART specifically suffers from poor urban service. As pointed out more than 15 years ago by Christof Spieler, it has very little service in San Francisco outside city center; Oakland service is awkward too, with most residential areas on a separate branch from Downtown Oakland. The Washington Metro has done this better.
  4. The A train in New York has the opposite problem as BART: the Rockaways tail was tacked on so awkwardly, at the end of a line that runs express but is still not fast enough – Far Rockaway-Times Square takes 1:08-1:10 for a distance of 37 km. The Green Line D Branch takes 46 minutes peak, 40 off-peak to traverse 19 km from Riverside to Government Center. PATH to Plainfield would likely have had the same problem; the core system is not fast, and with no through-service beyond its Manhattan terminals, it would have had cumbersome transfers for onward travel.

Conclusion

There are two models for how to extend rapid transit into the suburbs: the commuter rail model of the S-Bahn systems, Tokyo, and the RER, and the suburban metro model of Stockholm and China; Seoul uses the S-Bahn model where legacy lines exist and the suburban metro model otherwise. The segregation of mainline rail from all other forms of mass transit forced postwar America to select the latter model.

But implementation fell short. Construction costs were far too high even in the 1970s. Transit-oriented development ranged from mediocre in Washington to nonexistent elsewhere; the systems were built to interact with cars, not buses or streetcars or subways or commuter rail. And most of the lines failed at the basic feature of providing good urban and suburban service on the same system – they either were too slow through the city or didn’t make enough city stops.

Moreover, much of this failure has to be viewed in light of the distinction between S-Bahns and suburban metro systems. S-Bahns had better turn their outlying stations into nodes with bus service (timed with the train unless frequency is very high) and local retail, but Berlin is full of park-and-rides and underdeveloped stations and suburban Zurich is low-density. In contrast, suburban metros have to have the TOD intensity of Stockholm or suburban Seoul – their construction costs are higher, so they must be designed around higher ridership to compensate. This should have been especially paramount in the high-cost American context. But it wasn’t, so ridership is low relative to cost, and expansion is slow.

New York Commuter Rail Rolling Stock Needs

Last night I was asked on Twitter about the equipment needs for an integrated commuter rail system in New York, with through-running from the New Jersey side to the Long Island and Connecticut side. So without further ado, let’s work this out, based on different scenarios for how much infrastructure is built and how much capacity there is.

Assumptions on speed

The baseline assumptions in all scenarios should be,

  • The rolling stock is new – this is about a combined purchase of trains, so the trains should be late-model international EMUs with the appropriate performance specs.
  • Trains are single-deck, to speed up boarding and alighting in Manhattan.
  • The entire system is electrified and equipped with high platforms, to enable rapid acceleration and limit dwell times to 30 seconds, except at Grand Central and Penn Station, where they are 2 minutes each.
  • Non-geometric speed limits (such as difficult turnouts) are lifted through better track maintenance standards and the use of track renewal machines, and geometric speed limits are based on 300 mm of total equivalent cant, or a lateral acceleration of 2 m/s^2 in the horizontal plane.
  • However, speed limits through new urban tunnels, except those used by intercity trains, are at most 130 km/h even when interstations are long.
  • Every junction that needs to be grade-separated for reliability is.
  • Peak and reverse-peak service are symmetric (asymmetric service may not even save rolling stock if the peak is long enough).
  • Urban areas have infill stations as needed to provide coverage, except where lines are parallel to the subway, such as the LIRR Main Line west of Jamaica.
  • Timetables are padded 7% over the technical travel time, and the turnaround time is set at 10 minutes per terminal.

Line trip times

With the above assumptions in mind, let’s compute end-to-end trip times by line. Note that we do not care which lines match up with which lines east and west of Penn Station – the point is not to write complete timetables, but to estimate rolling stock needs. The shortcut we can take is that trains are sufficiently frequent at the peak that artifacts coming from the question of which lines match with which likes are not going to matter. Trip times without links are directly computed for the purposes of this post, and should be viewed as somewhat less certain, within a few percent in each direction.

TerminusService patternTrip time
Great NeckLocal0:32
Port WashingtonLocal0:39
HempsteadLocal0:37
East Garden CityLocal0:37
Far RockawayLocal0:39
Long BeachLocal0:40
West HempsteadLocal0:36
West Hempstead DinkyLocal0:10
BabylonLocal0:58
MontaukLocal2:20
HuntingtonExpress west of Floral Park0:43
Port JeffersonExpress west of Floral Park1:10
RonkonkomaExpress west of Floral Park0:57
GreenportExpress west of Floral Park1:42
Oyster Bay DinkyLocal0:25
New Rochelle (via NEC)Local0:26
New Rochelle (to GCT)Local0:21
Stamford (via NEC)Local0:50
Stamford (to GCT)Local0:45
New Haven (to GCT)Express south of Stamford1:18
New Canaan (to GCT)Express south of Stamford0:43
Danbury (to GCT)Express south of Stamford1:15
Waterbury (to GCT)Express south of Stamford1:40
North White PlainsLocal0:40
SoutheastLocal1:16
WassaicLocal1:48
Yonkers (to GCT)Local0:25
Yonkers (via West Side)Local0:23
Croton-Harmon (to GCT)Local0:52
Croton-Harrmon (via West Side)Local0:50
Poughkeepsie (to GCT)Express south of Croton1:12
Poughkeepsie (via West Side)Express south of Croton1:10
Jersey AvenueLocal0:41
TrentonLocal1:01
TrentonExpress north of New Brunswick0:52
Princeton DinkyLocal0:03
Long BranchLocal1:01
Bay HeadLocal1:23
RaritanLocal0:47
High BridgeLocal1:04
Dover (via Summit)Local1:00
Dover (via Montclair)Local1:04
Hackettstown (via Summit)Local1:22
Montclair State UniversityLocal0:33
GladstoneLocal1:08
SummitLocal0:34
Suffern (via Paterson)Local0:50
Suffern (via Radburn)Local0:47
Port Jervis (via Radburn)Local1:50
Spring ValleyLocal0:50
NyackLocal0:51
Tottenville (to GCT)Local0:47
Port Ivory (to GCT)Local0:28
GCT-Penn (with dwells)Local0:04
Jamaica-FiDi adjustmentLocal0:02

The last two adjustment numbers are designed to be added to other lines: Grand Central-Penn Station with 2 minute dwell times at each stop adds 4 minutes to the total trip time, net of savings from no longer having bumper tracks at Grand Central. The Staten Island numbers are also net of such savings. The Jamaica-Lower Manhattan adjustment reflects the fact that, I believe, Jamaica-Lower Manhattan commuter trains with several infill stops would take 0:19, compared with 0:17 on local trains to Penn Station (also with infill).

The 3-line system

The 3-line system is a bare Gateway tunnel with a continuing tunnel to Grand Central (Line 2) and a realignment of the Empire Connection to permit through-service to the northern tunnel pair under the East River (Line 3); Line 1 is, throughout this post, the present-day Hudson tunnel paired with the southern tunnel pair under the East River.

With no Lower Manhattan service, the Erie lines and the Staten Island lines would not be part of this system. Long Island would need to economize by cutting the West Hempstead Branch to a shuttle train connecting to frequent Atlantic Branch and Babylon Branch trains at Valley Stream. The Harlem Line would terminate at Grand Central. Moreover, the weakest tails of the lines today, that is to say Wassaic, Waterbury, Greenport, and Montauk, would not be part of this system – they should be permanently turned into short dinkies.

The table below makes some implicit assumptions about which lines run through and which do not; those that do only require one turnaround as they are paired at the Manhattan end. Overall this does not impact the regionwide fleet requirement.

Total peak service under this is likely to be,

TerminusTrip timeTphFleet size
Great Neck0:3268
Port Washington0:3969
Hempstead0:371217
Far Rockaway0:39610
Long Beach0:40610
West Hempstead Dinky0:1064
Babylon0:581228
Huntington0:43611
Port Jefferson1:10616
Ronkonkoma0:571227
Oyster Bay Dinky0:2534
Stamford (via NEC)0:50611
Stamford (to GCT, via Alt G)0:49611
New Haven (via Alt G)1:22618
New Canaan (via Alt G)0:4736
Danbury (via Alt G)1:1939
North White Plains0:401220
Southeast1:161235
Yonkers (to GCT, via Alt G)0:2967
Croton-Harmon (via West Side)0:50611
Poughkeepsie (via West Side)1:10615
Jersey Avenue0:41610
Trenton1:01614
Long Branch1:0137
Bay Head1:2339
Raritan0:4736
High Bridge1:0437
Dover (via Summit)1:0037
Dover (via Montclair)1:0437
Hackettstown1:2239
Montclair State U0:3334
Gladstone1:0838
Summit0:3434

This totals 379 trainsets; most should be 12 cars long, and only a minority should be as short as 8 cars; only the dinkies should be shorter than that. Off-peak, service is likely to be much less frequent – perhaps half as frequent on most lines, with some less frequent lines reduced to dinkies with timed connections to maintain base 20-minute frequencies – but the peak determines the capital needs, not the off-peak.

The 5-line system

The Lower Manhattan tunnels connecting Jersey City (or Hoboken) with Downtown Brooklyn and Grand Central with Staten Island make for a Line 4 (Harlem-Grand Central-Staten Island) and a Line 5 (Erie-Atlantic Branch). With such a system in place, more service can be run. The Babylon Branch no longer needs to use the Main Line west of Jamaica, making room for very frequent service on the Hempstead Line, with very high frequency to East Garden City.

In addition to the 379 trainsets for the 3-line system, rolling stock needs to be procured for Staten Island, the Erie lines, and incremental service for extra LIRR trains. In the table below, trip times for the Erie lines absorb the 2-minute adjustment for the LIRR trains they connect to; Staten Island lines are already reckoned from Grand Central. Dwell times for such lines are not included at all, as they are already included in the 3-line table.

The table also omits Port Jervis, as a tail of the Erie Main Line.

TerminusTrip timeTphFleet size
East Garden City0:371219
Suffern (via Paterson)0:5266
Suffern (via Radburn)0:4965
Spring Valley0:5266
Nyack0:5366
Tottenville0:471219
Port Ivory0:281212

This is an extra 73 trainsets, for a total of 452.

Further lines

Most of my maps also depict a Line 6 through-tunnel, connecting East Side Access with Hoboken and completely separating the Morris and Essex system from the Northeast Corridor. This only adds trains in New Jersey, including 6 on the M&E system (say, all turning at Summit, roughly at the outer end of high-density suburbanization), and presumably 6 on the Raritan Valley Line (all turning at Raritan or even closer in, such as at Westfield) and 12 on the Northeast Corridor and North Jersey Coast Line (say, 6 to Jersey Avenue, 3 to Long Branch, and 3 to Bay Head). This adds a total of 37 trainsets. As a sanity check, this is really half a line – all timetables, including the 3-line one, assume East Side Access exists – and the 5-line system with its extra 73 trainsets really only adds 2.5 half-lines (the Harlem Line and 5-minute Atlantic Branch service preexist) and those lines are shorter than average.

More speculative is a Line 7, connecting the Lower Montauk Line with an entirely new route through Manhattan to add capacity to New Jersey; this is justified by high commuter volumes from the Erie lines, which under the 6-line system have the highest present-day commute volume to New York divided by peak service. On the Long Island side, it entails restoring through-service to the West Hempstead Branch instead of reducing it to a dinky, changing a 4-trainset shuttle line into a 19-trainset ((36+10)*2*12/60) through-line, and also doubling service on the Far Rockaway and Long Beach Branches, adding a total of 20 trainsets, a total of 35 for the half-line. On the New Jersey side, it depends on what the service plan is for the Erie Lines and on what is done with the West Shore Line and the Susquehanna; the number of extra trainsets is likely about 40, making the 7-line system require about 600 trainsets.

If ridership grows to the point that outer tails like Wassaic, Waterbury, Greenport, and Montauk justify through-service, then this adds a handful of trains to each. Every hourly train to Southeast that extends to Wassaic requires slightly more than one extra trainset; every hourly train to Greenport requires 1.5 (thus, half-hourly requires 3); every hourly train to Montauk requires three. Direct service to Waterbury, displacing trains going to New Haven, is slightly less than one trainset per hourly train; the most likely schedule that fits everything else is a peak train every 20 minutes, which requires 2 extra trainsets.

How Washington Should Spend $10 Billion

The planned $10 billion expansion of Washington Union Station is a waste of money, but this does not mean that money appropriated for public transportation in the National Capital Region is a waste. The region has real transportation needs that should be addressed through urban rail expansion – just not through a rebuild of the intercity rail station. Those needs include local and regional travel, to be addressed through investment in both the Metro and the commuter rail networks. It is fortunate that when I probed on Twitter, there was broad if imperfect agreement among area advocates about what to do.

A $10 billion budget should be spent predominantly on new Metro Rail lines, carefully chosen to satisfy multiple goals at once: physical expansion of the reach of the system, additional core capacity, and deinterlining to improve reliability and increase the capacity of existing lines. For the purposes of the question I posed to area advocates, I set the expansion budget at $7.5 billion, good for 30 km at average global prices, leaving the rest for commuter rail improvements.

What to do about commuter rail

Washington does not have a large legacy commuter rail network, unlike New York, Chicago, Boston, or Philadelphia. It is not as old as those cities, and its conception as the southern end of an East Coast region stretching up to Boston is postwar, by which point investment in passenger rail was largely relegated to the past. Nonetheless, it does have some lines, three to the north as the MARC system and two to the south as the VRE system. They should be upgraded to better commuter rail standards.

Union Station already has the infrastructure for through-running. The junction between the through-tunnel and the terminal tracks is flat, and almost all intercity trains terminate and most will indefinitely no matter how much investment there is in high-speed rail to points south. This requires delicate scheduling, which is good up to about 18 trains per hour in each direction, either six through- and 12 terminating or the other way around. Running half-hourly all-day service on each of the lines, with some additional urban overlay in Virginia and extra service on the Penn Line to Baltimore, should not be too difficult.

Thus, the main spending items on the agenda are not new tracks, but electrification and high platforms. MARC runs diesel trains even under catenary on the Northeast Corridor, which problem requires no additional electrification to fix, but its other two lines are unelectrified, and VRE has no electrification infrastructure. Those lines total 327 route-km of required wiring, with extensive single-tracking reducing per-km cost; this should be around $600 million. But note that they all carry significant freight traffic, and additional accommodations may be necessary.

As far as platforms go, there are nearly 50 stations requiring high platforms (I think 49 but I may have miscounted). At Boston costs it should be $1 billion or a bit more, but that’s for long trains, and MARC trains are not so long, and a system based on shorter trains at higher frequency would be somewhat cheaper. Infill stations are probably unnecessary – there are Metro Rail lines along the inner sections of most of the lines providing the urban rail layer.

Metro Rail expansion

The most pressing problem WMATA’s trains have is poor reliability. Two changes in the late 2000s and 2010s made the system worse: the 2009 elimination of automatic (though not driverless) operations worsened ride quality and reducing capacity, and the 2014 opening of the Silver Line introduced too much interlining reducing both reliability and capacity. WMATA is aware of the first problem and is working to restore ATO; the Silver Line’s problems should be fixed through judicious use of deinterlining. Deinterlining by itself only requires a short extension of the Yellow Line to separate the lines, but it can be bundled with further expansion.

Consensus among area advocates is that there should be separate tunnels for the Yellow and Blue Lines and a new trunk line under Columbia Pike, which three lines total 21 km. Additional lines can consist of another trunk line going northeast from Union Station between the Brunswick and Camden Lines or an extension of the Columbia Pike line from Bailey’s Crossroads, the present outer limit of high density, to Annandale, which would require extension transit-oriented development along the line.

A full-size version can be found here; note that the lines at Union Station are moved around to get rid of the Red Line’s awkward U-shape. The northeast extension option is colored red but should be a Blue Line extension, but the Red Line taking over H Street and going to Largo.

How Many Tracks Do Train Stations Need?

A brief discussion on Reddit about my post criticizing Penn Station expansion plans led me to write a very long comment, which I’d like to hoist to a full post explaining how big an urban train station needs to be to serve regional and intercity rail traffic. The main principles are,

  • Good operations can substitute for station size, and it’s always cheaper to get the system to be more reliable than to build more tracks in city center.
  • Through-running reduces the required station footprint, and this is one of the reasons it is popular for urban commuter rail systems.
  • The simpler and more local the system is, the fewer tracks are needed: an urban commuter rail system running on captive tracks with no sharing tracks with other traffic and with limited branching an get away with smaller stations than an intercity rail station featuring trains from hundreds of kilometers away in any direction.

The formula for minimum headways

On subways, where usually the rush hour crunches are the worst, trains in large cities run extremely frequently, brushing up against the physical limitation of the tracks. The limit is dictated by the brick wall rule, which states that the signal system must at any point assume that the train ahead can turn into a brick wall and stop moving and the current train must be able to brake in time before it reaches it. Cars, for that matter, follow the same rule, but their emergency braking rate is much faster, so on a freeway they can follow two seconds apart. A metro train in theory could do the same with headways of 15 seconds, but in practice there are stations on the tracks and dealing with them requires a different formula.

With metro-style stations, without extra tracks, the governing formula is,

\mbox{headway } = \mbox{stopping time } + \mbox{dwell time } + \mbox{platform clearing time }

Platform clearing time is how long it takes the train to clear its own length; the idea of the formula is that per the brick wall rule, the train we’re on needs to begin braking to enter the next station only after the train ahead of ours has cleared the station.

But all of this is in theory. In practice, there are uncertainties. The uncertainties are almost never in the stopping or platform clearing time, and even the dwell time is controllable. Rather, the schedule itself is uncertain: our train can be a minute late, which for our purpose as passengers may be unimportant, but for the scheduler and dispatcher on a congested line means that all the trains behind ours have to also be delayed by a minute.

What this means that more space is required between train slots to make schedules recoverable. Moreover, the more complex the line’s operations are, the more space is needed. On a metro train running on captive tracks, if all trains are delayed by a minute, it’s really not a big deal even to the control tower; all the trains substitute for one another, so the recovery can be done at the terminal. On a mainline train running on a national network in which our segment can host trains to Budapest, Vienna, Prague, Leipzig, Munich, Zurich, Stuttgart, Frankfurt, and Paris, trains cannot substitute for one another – and, moreover, a train can be easily delayed 15 minutes and need a later slot. Empty-looking space in the track timetable is unavoidable – if the schedule can’t survive contact with the passengers, it’s not a schedule but crayon.

How to improve operations

In one word: reliability.

In two words: more reliability.

Because the main limit to rail frequency on congested track comes from the variation in the schedule, the best way to increase capacity is to reduce the variation in the schedule. This, in turn, has two aspects: reducing the likelihood of a delay, and reducing the ability of a delay to propagate.

Reducing delays

The central insight about delays is that they may occur anywhere on the line, roughly in proportion to either trip time or ridership. This means that on a branched mainline railway network, delays almost never originate at the city center train station or its approaches, not because that part of the system is uniquely reliable, but because the train might spend five minutes there out of a one-hour trip. The upshot is that to make a congested central segment more reliable, it is necessary to invest in reliability on the entire network, most of which consists of branch segments that by themselves do not have capacity crunches.

The biggest required investments for this are electrification and level boarding. Both have many benefits other than schedule reliability, and are underrated in Europe and even more underrated in the United States.

Electrification is the subject of a TransitMatters report from last year. As far as reliability is concerned, the LIRR and Metro-North’s diesel locomotives average about 20 times the mechanical failure rate of electric multiple units (source, PDF-pp. 36 and 151). It is bad enough that Germany is keeping some outer regional rail branches in the exurbs of Berlin and Munich unwired; that New York has not fully electrified is unconscionable.

Level boarding is comparable in its importance. It not only reduces dwell time, but also reduces variability in dwell time. With about a meter of vertical gap between platform and train floor, Mansfield has four-minute rush hour dwell times; this is the busiest suburban Boston commuter rail station at rush hour, but it’s still just about 2,000 weekday boardings, whereas RER and S-Bahn stations with 10 time the traffic hold to a 30-second standard. This also interacts positively with accessibility: it permits passengers in wheelchairs to board unaided, which both improves accessibility and ensures that a wheelchair user doesn’t delay the entire train by a minute. It is fortunate that the LIRR and (with one peripheral exception) Metro-North are entirely high-platform, and unfortunate that New Jersey Transit is not.

Reducing delay propagation

Even with reliable mechanical and civil engineering, delays are inevitable. The real innovations in Switzerland giving it Europe’s most reliable and highest-use railway network are not about preventing delays from happening (it is fully electrified but a laggard on level boarding). They’re about ensuring delays do not propagate across the network. This is especially notable as the network relies on timed connections and overtakes, both of which require schedule discipline. Achieving such discipline requires the following operations and capital treatments:

  • Uniform timetable padding of about 7%, applied throughout the line roughly on a one minute in 15 basis.
  • Clear, non-discriminatory rules about train priority, including a rule that a train that’s more than 30 minutes loses all priority and may not delay other trains at junctions or on shared tracks.
  • A rigid clockface schedule or Takt, where the problem sections (overtakes, meets, etc.) are predictable and can receive investment. With the Takt system, even urban commuter lines can be left partly single-track, as long as the timetable is such that trains in opposite directions meet away from the bottleneck.
  • Data-oriented planning that focuses on tracing the sources of major delays and feeding the information to capital planning so that problem sections can, again, receive capital investment.
  • Especial concern for railway junctions, which are to be grade-separated or consistently scheduled around. In sensitive cases where traffic is heavy and grade separation is too expensive, Switzerland builds pocket tracks at-grade, so that a late train can wait for a slot without delaying cross-traffic.

So, how big do train stations need to be?

A multi-station urban commuter rail trunk can get away with metro-style operations, with a single station track per approach track. However, the limiting factor to capacity will be station dwell times. In cases with an unusually busy city center station, or on a highly-interlinked regional or intercity network, this may force compromises on capacity.

In contrast, with good operations, a train station with through-running should never need more than two station tracks per approach track. Moreover, the two station tracks that each approach track splits into should serve the same platform, so that if there is an unplanned rescheduling of the train, passengers should be able to use the usual platform at least. Berlin Hauptbahnhof’s deep tracks are organized this way, and so is the under-construction Stuttgart 21.

Why two? First, because it is the maximum number that can serve the same platform; if they serve different platforms, it may require lengthening dwell times during unscheduled diversions to deal with passenger confusion. And second, because every additional platform track permits, in theory, an increase in the dwell time equal to the minimum headway. The minimum headway in practice is going to be about 120 seconds; at rush hour Paris pushes 32 trains per hour on the shared RER B and D trunk, which is not quite mainline but is extensively branched, but the reliability is legendarily poor. With a two-minute headway, the two-platform track system permits a straightforward 2.5-minute dwell time, which is more than any regional railway needs; the Zurich S-Bahn has 60-second dwells at Hauptbahnhof, and the Paris RER’s single-level trains keep to about 60 seconds at rush hour in city center as well.

All of this is more complicated at a terminal. In theory the required number of tracks is the minimum turn time divided by the headway, but in practice the turn time has a variance. Tokyo has been able to push station footprint to a minimum, with two tracks at Tokyo Station on the Chuo Line (with 28 peak trains per hour) and, before the through-line opened, four tracks on the Tokaido Main Line (with 24). But elsewhere the results are less optimistic; Paris is limited to 16-18 trains per hour at the four-track RER E terminal at Saint-Lazare.

At Paris’s levels of efficiency, which are well below global best practices, an unexpanded Penn Station without through-running would still need two permanent tracks for Amtrak, leaving 19 tracks for commuter traffic. With the Gateway tunnel built, there would be four two-track approaches, two from each direction. The approaches that share tracks with Amtrak (North River Tunnels, southern pair of East River Tunnels) would get four tracks each, enough to terminate around 18 trains per hour at rush hour, and the approaches that don’t would get five, enough for maybe 20 or 22. The worst bottleneck in the system, the New Jersey approach, would be improved from today’s 21 trains per hour to 38-40.

A Penn Station with through-running does not have the 38-40 trains per hour limit. Rather, the approach tracks would become the primary bottleneck, and it would take an expansion to eight approach tracks on each side for the station itself to be at all a limit.

The Northeastern United States Wants to Set Tens of Billions on Fire Again

The prospect of federal funds from the Bipartisan Infrastructure Bill is getting every agency salivating with desires for outside money for both useful and useless priorities. Northeastern mainline rail, unfortunately, tilts heavily toward the useless, per a deep dive into documents by New York-area activists, for example here and here.

Amtrak is already hiring project management for Penn Station redevelopment. This is a project with no transportation value whatsoever: this is not the Gateway tunnels, which stand to double capacity across the Hudson, but rather a rebuild of Penn Station to add more tracks, which are not necessary. Amtrak’s current claim is that the cost just for renovating the existing station is $6.5 billion and that of adding tracks is $10.5 billion; the latter project has ballooned from seven tracks to 9-12 tracks, to be built on two levels.

This is complete overkill. New train stations in big cities are uncommon, but they do exist, and where tracks are tunneled, the standard is two platform tracks per approach tracks. This is how Berlin Hauptbahnhof’s deep section goes: the North-South Main Line is four tracks, and the station has eight, on four platforms. Stuttgart 21 is planned in the same way. In the best case, each of the approach track splits into two tracks and the two tracks serve the same platform. Penn Station has 21 tracks and, with the maximal post-Gateway scenario, six approach tracks on each side; therefore, extra tracks are not needed. What’s more, bundling 12 platform tracks into a project that adds just two approach tracks is pointless.

This is a combined $17 billion that Amtrak wants to spend with no benefit whatsoever; this budget by itself could build high-speed rail from Boston to Washington.

Or at least it could if any of the railroads on the Northeast Corridor were both interested and expert in high-speed rail construction. Connecticut is planning on $8-10 billion just to do track repairs aiming at cutting 25-30 minutes from the New York-New Haven trip times; as I wrote last year when these plans were first released, the reconstruction required to cut around 40 minutes and also upgrade the branches is similar in scope to ongoing renovations of Germany’s oldest and longest high-speed line, which cost 640M€ as a once in a generation project.

In addition to spending about an order of magnitude too much on a smaller project, Connecticut also thinks the New Haven Line needs a dedicated freight track. The extent of freight traffic on the line is unclear, since the consultant report‘s stated numbers are self-contradictory and look like a typo, but it looks like there are 11 trains on the line every day. With some constraints, this traffic fits in the evening off-peak without the need for nighttime operations. With no constraints, it fits on a single track at night, and because the corridor has four tracks, it’s possible to isolate one local track for freight while maintenance is done (with a track renewal machine, which US passenger railroads do not use) on the two tracks not adjacent to it. The cost of the extra freight track and the other order-of-magnitude-too-costly state of good repair elements, including about 100% extra for procurement extras (force account, contingency, etc.), is $300 million for 5.4 km.

I would counsel the federal government not to fund any of this. The costs are too high, the benefits are at best minimal and at worst worse than nothing, and the agencies in question have shown time and time again that they are incurious of best practices. There is no path forward with those agencies and their leadership staying in place; removal of senior management at the state DOTs, agencies, and Amtrak and their replacement with people with experience of executing successful mainline rail projects is necessary. Those people, moreover, are mid-level European and Asian engineers working as civil servants, and not consultants or political appointees. The role of the top political layer is to insulate those engineers from pressure by anti-modern interest groups such as petty local politicians and traditional railroaders who for whatever reasons could not just be removed.

If federal agencies are interested in building something useful with the tens of billions of BIL money, they should instead demand the same results seen in countries where the main language is not English, and staff up permanent civil service run by people with experience in those countries. Following best industry practices, $17 billion is enough to renovate the parts of the Northeast Corridor that require renovation and bypass those that require greenfield bypasses; even without Gateway, Amtrak can squeeze a 16-car train every 15 minutes, providing 4,400 seats into Penn Station in an hour, compared with around 1,700 today – and Gateway itself is doable for low single-digit billions given better planning and engineering.

Tails on Commuter Rail

An interesting discussion on Twitter came out of an alternatives analysis for Philadelphia commuter rail improvements. I don’t want to discuss the issue at hand for now (namely, forced transfers), but the discussion of Philadelphia leads to a broader question about tails. Commuter rail systems sometimes have low-frequency tails with through-service to the core system and sometimes don’t, and it’s useful to understand both approaches.

What is a tail?

For the purposes of this post, a tail is whenever there is a frequent line with trains infrequently continuing farther out. Frequency here is relative, so a subway line running every 2.5 minutes to a destination with every fourth train continuing onward is a tail even though the tail still has 10-minute frequency, and a commuter line running every 20 minutes with every third train continuing onward also has a tail, even though in the latter case the core frequency is lower than the tail frequency in the former case.

The key here is that the line serves two markets, one high-intensity and frequent and one lower-intensity warranting less service, with the outer travel market running through to the inner one. Usually the implication is that the inner segment can survive on its own and the contribution of the outer segment to ridership is not significant by itself. In contrast, it’s common enough on S-Bahn systems to have a very frequent trunk (as in Berlin, or Munich, or Paris) that fundamentally depends on through-service from many suburban segments farther out combining to support high frequency in the core; if ridership farther out is significant enough that without it frequency in the core would suffer, I would not call this a tail.

When are tails useful?

Tails are useful whenever there is a core line that happens to be along the same route as a lower-intensity suburban line. In that case, the suburban line behind can benefit from the strong service in the core by having direct through-service to it at a frequency that’s probably higher than it could support by itself. This is especially valuable as the ridership of the tail grows in proportion to that of the core segment – in the limiting case, it’s not even a tail, just outer branches that combine to support strong core frequency.

Tokyo makes extensive use of tails. The JR East commuter lines all have putative natural ends within the urban area. For example, most Chuo Rapid Line trains turn at Takao, at the western end of the built-up area of Tokyo – but some continue onward to the west, running as regional trains to Otsuki or as interregional or as intercity trains farther west to Shiojiri.

Munich and Zurich both use tails as well on their S-Bahns. In Munich, the base frequency of each of the seven main services is every 20 minutes, but some have tails running hourly, and all have tails running two trains per hour with awkward alternation of 20- and 40-minute gaps. In Zurich, the system is more complex, and some lines have tails (for example, S4) and some do not (for example, S3); S4 is not a portion of an intercity line the way the Chuo Line is, and yet its terminus only gets hourly trains, while most of the line gets a train every 20 minutes.

What are the drawbacks of tails?

A tail is a commitment to running similar service as in the core, just at lower frequency. In Philadelphia, the proposal to avoid tails and instead force what would be tails into off-peak shuttle trains with timed transfers to the core system is bundled into separate brands for inner and outer service and a desire to keep the outer stations underbuilt, without accessibility or high platforms. Branding is an exercise in futility in this context, but there are, in other places than Philadelphia, legitimate reasons to avoid tails, as in Paris and Berlin:

  • Different construction standards – perhaps the core is electrified and an outer segment is not; historically, this was the reason Philadelphia ended commuter rail service past the limit of electrification, becoming the only all-electrified American commuter rail network. In Berlin, the electrification standards on the mainline and on the S-Bahn differ as the S-Bahn was electrified decades earlier and is run as an almost entirely self-contained system.
  • Train size difference – sometimes the gap in demand is such that the tail needs not just lower frequency than the core but also shorter trains. In the United States, Trenton is a good example of this – New York-Trenton is a much higher-demand line than Trenton-Philadelphia and runs longer trains, which is one reason commuter trains do not run through.
  • Extra tracks – if there are express tracks on the core segment, then it may be desirable to run a tail express, if it is part of an intercity line like the Chuo Line rather than an isolated regional line like S4 in Zurich, and not have it interface with the core commuter line at all to avoid timetabling complications. If there are no extra tracks, then the tail would have to terminate at the connection point with the core line, as is proposed in Philadelphia, and the forced transfer is a drawback that generally justifies running the tail.

Do the drawbacks justify curtailment?

Not really. On two-track lines, it’s useful to provide service into city center from the entire line, just maybe not at high frequency on outer segments. This can create situations in which intercity-scale lines run as commuter rail lines that keep going farther than typical, and this is fine – the JR East lines do this on their rapid track pairs and within the built-up area of Tokyo people use those longer-range trains in the same way they would an ordinary rapid commuter train.

This is especially important to understand in the United States, which is poor in four-track approaches of the kind that the largest European cities have. I think both Paris and Berlin should be incorporating their regional lines into the core RER and S-Bahn as tails, but they make it work without this by running those trains on dedicated tracks shared with intercity service but not commuter rail. Boston, New York, and Philadelphia do not have this ability, because they lack the ability to segregate S-Bahn and RegionalBahn services. This means Boston should be running trains to Cape Cod, Manchester, and Springfield as tails of the core system, and New York should electrify its entire system and run trains to the Hamptons as LIRR tails, and Philadelphia should run tail trains to the entire reach of its commuter rail system.

Quick Note: Regional Rail and the Massachusetts State Legislature

The Massachusetts state legislature is shrugging off commuter rail improvements, and in particular ignoring calls to spend some starter money on the Regional Rail plan. The state’s climate bill ignores public transportation, and an amendment proposing to include commuter rail electrification in the plan has been proposed but not yet included in the plan. Much of the dithering appears to be the fault of one politician: Will Brownsberger, who represents Watertown, Belmont, Back Bay, and parts of Brighton.

What is Regional Rail?

Regional Rail is a proposal by TransitMatters to modernize the MBTA commuter rail network to align it with the standards that have emerged in the last 50-60 years. The centerpiece of the plan is electrification of the entire network, starting from the already-wired Providence Line and the short, urban Fairmount Line and inner Eastern Line (Newburyport/Rockport Lines on timetables).

Based on comparable projects in peer countries, full electrification should cost $0.8-1.5 billion, and station upgrades to permit step-free access should cost on the order of $2 billion; rolling stock costs extra upfront but has half the lifecycle costs of diesels. An investment program on the order of high hundreds of millions or very low billions should be sufficient to wire the early-action lines as well as some more, such as the Worcester Line; one in the mid-single digit billions should be enough to wire everything, upgrade all stations, and procure modern trains.

Benefits include much faster trips (see trip planner here), lower operating and maintenance costs, higher reliability, and lower air and noise pollution and greenhouse gas emissions. For a city the size of Boston, benefits exceed costs by such a margin that in the developed world outside North America, it would have been fully wired generations ago, and today’s frontier of commuter rail electrification is sub-million metro areas like Trondheim, Aarhus, and Cardiff.

Who is Will Brownsberger?

Brownsberger is a Massachusetts state senator, currently serving as the Senate’s president pro tempore. His district is a mix of middle-class urban and middle-class inner-suburban; the great majority of his district would benefit from commuter rail modernization.

He has strong opinions on commuter rail, which are what someone unaware of any progress in the industry since roughly 1960 might think are the future. For example, here’s a blog post he wrote in 2019, saying that diesel engines are more reliable than electric trains because what if there’s a power outage (on American commuter rail systems that operate both kinds of vehicles, electric trains are about an order of magnitude more reliable), and ending up saying rail is an outdated 20th century concept and proposing small-scale autonomous vehicles running on the right-of-way instead. More recently, he’s told constituents that rail electrification with overhead wire is impossibly difficult and the only option is battery-electric trains.

Because he’s written about the subject, and because of his position in the State Senate and the party caucus, he’s treated as an authority on the subject. Hence, the legislature’s lack of interest in rail modernization. It’s likely that what he tells constituents is also what he tells other legislators, who follow his lead while focusing on their own personal interest, such as health policy, education policy, taxes, or any other item on the liberal policy menu.

Why is he like this?

I don’t know. It’s not some kind of nefarious interest against modernization, such as the trenchant opposition of New York suburbanites to any policy that would make commuter trains useful for city residents, who they look down on. Brownsberger’s district is fairly urban, and in particular Watertown and Belmont residents would benefit greatly from a system that runs frequently all day at 2020s speeds and not 1920s speeds. Brownsberger’s politics are pretty conventionally liberal and he is interested in sustainability.

More likely, it’s not-invented-here syndrome. American mainline passenger rail is stuck in the 1950s. Every innovation in the field since then has come from outside North America, and many have not been implemented in any country that speaks English as its primary language. Brownsberger lacks this knowledge; a lifetime in politics does not lend itself well to forming a deep web of transnational relationships that one can leverage for the required learning.

Without the benefit of around 60 years of accumulated knowledge of French, German, Swiss, Swedish, Dutch, Japanese, Korean, Austrian, Hungarian, Czech, Turkish, Italian, and Spanish commuter rail planning, any American plan would have to reinvent the wheel. Sometimes it happens to reinvent a wheel that is round and has spokes; more often, it invents a wheel with sharp corners or no place to even attach an axle.

When learning happens, it is so haphazard that it’s very easy to learn wrong or speculative things. Battery-electric trains are a good example of this. Europe is currently experimenting with battery-electric trains on low-traffic lines, where the fact that battery-electrics cost around double what conventional electric multiple units do is less important because traffic is that light. The technology is thus on the vendors’ mind and so when Americans ask, the vendors offer to sell what they’ve made. Boston is region of 8 million people running eight- and nine-car trains every 15 minutes at rush hour, where the places in Europe that experiment with battery tech run an hourly three-car train, but the without enough background in how urban commuter rail works in Europe, it’s easy for an American agency executive or politician to overlook this difference.

Is there a way forward?

Yes!

Here is a proposed amendment, numbered Amendment 13, by Senator Brendan Crighton. Crighton represents some of the suburbs to the northeast of Boston, including working-class Lynn and very posh Marblehead; with only four years in the State Senate and three in the Assembly, he’s not far up the food chain. But he proposed to require full electrification of the commuter rail network as part of the climate bill, on a loose schedule in which no new diesels may be procured after 2030, and lines would be electrified by 2028 (the above-named early action lines) to 2035 (the rest of the system). There are so far four cosponsors in addition to Crighton, and good transit activists in Massachusetts should push for more sponsorship so that Amendment 13 makes it into the climate package and passes.