Tradeoffs in Reliability and Shutdowns
I am writing this post riding trains between Brussels and Berlin. My connection in Cologne was canceled as the connecting train was moved to depart earlier than my first train’s arrival time, and somehow, it is faster to stay on the train until Frankfurt and connect there, the trains between Cologne and Berlin are so disturbed this summer. Cologne-Berlin, normally a direct hourly connection in 4-4.5 hours, is slowed to 5.5 hours every two hours this summer. It got me thinking about something Jon Worth said last month about the importance of public transport being there, including at night, because it reminded me of how there are always tradeoffs. Train service cannot literally run 24/7 without changes; maintenance windows are required. So it’s a question of tradeoffs – when service must run less reliably, or not at all. Deutsche Bahn has unfortunately chosen a grossly wrong side of the tradeoff, leading to summertime shutdowns and slowdowns that its French and Japanese peers simply do not have. Those shutdowns, in turn, are, these days, leading to catastrophic levels of popular mistrust in DB.
The tradeoffs
I wrote six weeks ago about the problems of summer maintenance in Germany. But, more generally, there is a tradeoff between span of service on a railway and how consistently service can be delivered. A railway that runs overnight will not have regular maintenance windows, and therefore have to pick some low-traffic period for a special disturbance. On the New York City Subway, this is the weekend: New York City Transit exploits its four-track mainlines and high levels of redundancy in most of the city to shut down individual sections of track on weekends and tell passengers to use alternatives. In Europe, it’s more common for this to be the summer period, when local travel is lower as people go on vacation; unfortunately, in Germany, this extends to intercity rail, during the high season of travel.
Jon says that, “That 5am train with a dozen building workers on it, or the last train home in the evening matter for the trust and reliability of the system, even if those individual trains make heavy losses and are largely empty.” But the point is that knowing that I can book a train in July and have it run as expected without being rerouted onto the slow line is, like the 5 am train, a matter of trust and reliability too. It’s just a matter of which matter of reliability is easier to compromise on.
Then there is a tradeoff of all of this against maintenance efficiency. It is more efficient from the perspective of minimum total gross hours of shutdown to have a long continuous period of shutdown, such as the four-month period planned for the Riedbahn. Nighttime shutdowns require an hour of preparation and disassembly at each end, so that a five-hour nighttime shutdown only yields three hours of maintenance work. Some systems don’t make that work even with regular nighttime shutdowns, such as the London Underground or American systems that are not New York; notably, the Berlin U-Bahn manages to avoid this even with overnight service on weekends.
The situation in Germany
DB’s response to the tradeoffs outlined above is to attempt to run all day, including occasionally at night. There are night trains between Hamburg and southern Germany on the Frankfurt-Cologne high-speed line, so even this line, without any nighttime freight (the grades are far too steep), does not have the regular maintenance windows that LGVs and Shinkansen lines have. As a result, last month, the line was shut for maintenance, and trains were diverted to the old line, taking an hour longer. Right now, the same diversions apply to Cologne-Berlin trains, slowing them by about an hour.
These are not peripheral connections. Frankfurt-Cologne is not quite the busiest intercity line in Germany – that would be the Riedbahn – but it’s a fairly close second, with the same planned traffic level in the Deutschlandtakt of six trains per hour in each direction. It’s the primary connection between the Rhine-Ruhr and not just Frankfurt but also all of southern Germany. Then, Berlin-Cologne connects the two largest metro areas in Germany; the Rhine-Ruhr is close in population to Ile-de-France, while Berlin and Brandenburg have more people than Rhône-Alpes or PACA, which has implications for how much traffic this connection would have if it were fast and reliable, which it is neither (government officials fly between Berlin and Bonn instead of relying on DB).
Is this unavoidable?
No. France has none of these daytime shutdowns on its main lines. Neither does Japan.
German rail advocates sneer at France and ignore Japan, finding all manners of reasons to avoid learning from countries that, on this point, are Germany’s superiors. A common line from within Germany is that its secondary lines are in better shape than France’s, so there is nothing to learn from France. But then, the reason there are routine hour-long delays (or longer) in the summer on the main lines is not that DB runs better service to a city like Siegen or Münster or Jena than SNCF does to their French peers.
The path forward has to be, at the technical level, to institute regular nighttime maintenance windows, and stop trying to make night trains happen. At infrastructure level, it must be to avoid building dual-use infrastructure, and build passenger-dedicated high-speed lines; if freight capacity is needed that the old lines with just slow regional trains can’t provide, then build a separate freight line, based on the needs of freight, at costs that are going to be lower than the long tunnels required for dual-use lines.
But the most important change has to be at the level of governance and culture. Germany believes itself to be at the top of the world. To borrow a joke about Japanese technological stagnation, there is an element here that visiting a German infrastructure system in 2005 had a futuristic vibe like visiting the year 2015, and visiting it today is still like visiting the year 2015. There’s a slew of problems in Germany for which the solution really is “be less German and more French,” and this is one of them, no matter what people who think all French people are unemployed rioters think.
Pedestrian Observations 
There is definitely unambiguous clear water between the UK and the French and the UK and the Germans on reliability – and we are in the middle.
So if the Germans cannot see that that is very disappointing.
While the UK isn’t as bad trying all night everywhere. Too many of the intercity go that extra hour too late so the maintenece window is 01:00-05:00 rather than 11:30-5:30. I wonder if there are also variable cost advantages to having longer maintence windows.
But having a Midnight cut-off is definitely one my triage emergency measures I’d be doing right now in the UK.
I think it should be different on different days of the week.
Friday/Saturday evening having a train leaving city centres at midnight or a little later seems reasonable – and it also should be worth a try to see what can be done for special events.
But perhaps the quid-pro-quo on that is the last service the rest of the time leaving at 11 to 11:30pm.
Japan’s cutoff is usually midnight, right? But then Yamanote is somehow 4-1…
somewhere between midnight and 23:30 generally.
The Tokyo city centre urban lines have the latest closing times and the earliest opening times. Shinkansen/Intercity outer-suburban the cut-off earlier (also fits into getting trains to depots in those locations). I had a quick spot-check of some Kansai rail hubs and its the same there.
Something like this would be great compromise. But it would take the 1. The Industry showing the cost structure to itself, the minister and the public, plus admission that there are solution other than moar money. 2. Ministers eating the whingeing.
One interesting nugget about Japan not being a 24-hour city (which they have a bit of a complex about), it means you get a lot mini-hotels around rail-hubs for “missed the last train” salarymen, the famous capsule hotels, net cafes etc. Personally I also think the train cut-off also works as some restraint of overwork culture.
N/B Curiously when during COVID the rail companies wished to cut costs, they reduced the latest timed trains first. Which suggests marginal costs of those services are high.
I think the lack of electrification hurts us as well. If the Chiltern mainline and Didcot-Coventry were electrified there would be 3 separate routes for late night trains between London and Birmingham.
Isn’t most of the difference an artifact of the Yamanote Line being a loop? Most of the suburban trains have a “last train” around midnight, but people are still on that train until close to 1.
The last Yamanote Line Outer Loop departs Shibuya at 0:33 to end in Ikebukuro at 0:54, but the last Shonan-Shinjuku Line northbound departs Shibuya at 23:27 which seems much earlier, but ends in Kagohara at 0:52.
Since the Yamanote Line is a loop, the last trains wrap around and keep serving the same stations later. I think the trains do tend to actually start earlier and end later, but not by anything close to what a first glance at schedules at its stations would suggest.
Germany and Austria are also highly enthusiastic about running sleeper train networks. While for now they use the legacy lines (since by their nature they can take 8+ hours to cover connections that daytime trains make in ~4 h), there are some noises that if they were allowed to use high-speed lines overnight, they could be competitive on e.g. Paris-Vienna or even longer stretches, where in the daytime sector, planes beat trains hands down.
Paris-Vienna would be a lot more compelling with a direct 2 hourly service.
As it is the service is probably 2 hourly with a change in Stuttgart and Munich which is pretty shit.
Stuttgart-Paris should be at least hourly as well.
Why is it that US agencies still need weekend shutdowns on top of night closures?
I think it’s just inefficiency in maintenance. My suspicion is that they benchmark themselves to New York and to one another so they haven’t figured out how not to do this; TfL has the same problem of seriously screwed up weekend service. BVG has other problems, like the highest rolling stock procurement costs in the world, but its service reliability is pretty good, without the weekend screwups of London or the summer shutdowns of Paris.
They sit around and discuss how they don’t need all that big city folderol. if they discuss it all. And since it’s only desperation users, who cares?
In Boston it’s very much not desperation users. Same in Washington, Chicago, San Francisco, Philadelphia, Seattle…
I suspect the people running transit don’t know that. They see the numbers in the reports of course, but they don’t internalize it and so they think of the executive riding the subway to a wall street job as a desperation user too poor to afford a car. How many of them use their own transit system vs drive (we hear about it when it happens regularly as if this is unusual)
@Henry, I believe one of the reasons Chiltern is good is because the executives actually do use it.
I very much doubt benchmarking to even nyc is occurring. I suspect a lot has to do with low mechanization levels of maintenance. Septa for example did? does? not have a vac train
Berlin has plenty of long-term shutdowns for heavy-duty maintenance. The northern part of the U6 is closed for several months right now, with replacement bus service. The U1/U3 went through a major closure a couple of years ago. And the North-South S-Bahn closes for a couple of weeks every February.
As for intercity trains, surely you can provide overnight services with low enough frequencies (a couple of times a night), that you only need to occupy one track, while the other track has work done on it? Obviously you might need to run slowly past any active work sites, but overnight trains generally don’t need to run to maximum speed anyway.
The S-Bahn has common closures, yeah. But on the U-Bahn it’s much rarer – it happens a bunch on U1/U3, but I can’t recall the last time U8 had this, and on U2 the months of single-tracking around Alexanderplatz were not about routine maintenance but about a fuckup with building foundations breaching the tunnel IIRC.
All U-Bahn lines experience significant closures for maintenance, but the cycles for those are very long, like once every decade or two (the North-South S-Bahn line is done more often due to excessive curvature, apparently). So you probably just haven’t experienced the U8 closing yet, but it’s probably due for it some time soon.
What made the situation with the U2 last year a little less intolerable is the fact that the BVG also has a lot of experience running Pendelverkehr to operate around limited maintenance sites late at night or on weekends.
I don’t think the current closure is the first time I see this on the Stadtbahn. I distinctly remember a 20-minute Takt a few years ago, if not full closure.
It’s difficult to credibly argue that https://content.tfl.gov.uk/planned-track-closures.pdf amounts to “seriously screwed up weekend service”. Yeah there’s a lot in there. But a lot of it is late night overground closures.
Thinking back to when I had aregularscheduled jobs in Chicago, then particularly NYC, I often worked a “swing shift” at the various bookstores. Thus “owl” service on transit was a necessity. Beyond that, if out for dinner, film(s?), or music (particularly jazz or the late sets at Rillmore East, Winterland in SF, and) getting home after the show broke at 2AM or laterwould not bepossible without at least a skeletal owl service. NYC in the 60s was a genuinely 24 hour city although I realize that many fewer venues run as late now as then. In the same vein, going down to Philly for music was common and easy enough that Philly venues would advertise shows in the Village Voice. A PRR train around midnight got one back to NYC with time for enough sleep to function the next work day.
So, in urban transit, and dense corridors like the NEC, I favor 24/7 as normal with short segments of single tracking or bus bridges as necessary for maintenance. It can be done without huge inconvenience.
As to mainline RR services, I start from the basis that single track so called mainlines as are common in much of post Staggers, thus post mergers based on buying up competitionn then shutting it down, are demonstrably insufficient for freight let alone reliable scheduled passenger services.
When I run numbers assuming “reasonable” construction costs and ticket prices I conclude that you need to be running 3 trains per hour all day to make building a high speed line worthwhile. Even then you are putting in stations for timed passing, on single track lines and not where they make the most sense. You can make the numbers work for just 2 trains per hour, but the trains have to be crowded all day which seems unlikely (there are peaks and valleys in demand). At 4 trains per hour or more you may as well run double track lines and at that point you should separate them enough to run single track service at night while doing maintenance on the other track (though I’ll admit I don’t know how much separation is needed and thus how feasible this is)
I think that much of it has to do with efficiency (or lack thereof) in maintenance practices. For example, BART does shut down at night, and won’t entertain 24-hour service only on weekends. However, since their trains run only every 20 mins in the evening, couldn’t they create night service that runs trains every 30 mins on a single track? I think that nearly all tunnels are single-track, so there’s inherent protection there.
Can’t the 3rd rail be shutdown with the right level of precision? Can we work on NB switches one night and SB switches another night? Don’t we have power redundancy to shutdown one substation for service while another one provides power?
All of that can be done – but you need the system to be designed for that upfront. You can’t close a substation if the wires to the redundant one are not large enough for the additional distance.
Which switches you close is not NB or SB, it is you design the schedule without specific switches, and then a different schedule the next night with different switches not used. A switch not used means no trains cross it at all. (though maybe if it is only one train per hour you can get all the work done in that hour including setup/cleanup – putting some grease in is different from replacing a foundation) If there is any switch that you cannot bypass for maintenance then you need to shut the whole line down.
Of course you have the option of shutting down the line and running a bus. sometimes this is just as good as running the line, other times it is worse. (it is hard to get bus drivers for those shifts, you may not have roads that work as a useful bypass, or some other reason I can’t think of).
All of this needs to start with engineering staff in the office working out what maintenance needs to be done and what the schedules look like to get it done. If you haven’t done this already you probably need to build new switches and bypasses, and you may even need to rebuild one whole direction of the line (to provide safety separation).
@Alon: Do you have any evidence that DB is habitually closing lines for maintenance in the summer or are you still extrapolating from this one trip you couldn’t take five years ago? Because I’ve taken trains in Germany very frequently over many years and never noticed any summer closures for regular maintenance.
The current closures are not something that is happening routinely, let alone every year. They are tackling the maintenance backlog after 16 years of neglect under Merkel by basically replacing everything. On the Frankfurt–Cologne line they replaced 70 km of tracks and 13 switches and worked on the airport station. I’m not sure they ever had such a long closure before on that line.
The Hanover-Würzburg and I think also Stuttgart-Mannheim mid-life renewal involved long-term closures in segments (not just in the summer, IIRC); this is ongoing but it’s been scheduled since the late 2010s – this isn’t the same as the Wissing-era emergency closure of the Riedbahn.
Stuttgart–Mannheim was indeed closed for 6 months in 2020—for a fundamental overhaul after 28 years in service: https://db-engineering-consulting.com/en/projects/permanent-way-improvements-for-the-mannheim-stuttgart-high-speed-line/ Not something they do every year.
Maybe your complaint is not about periodic summer maintenance, where they would shut down the same line for some time every summer, but that such fundamental overhauls should be done differently, even if they only happen once in a few decades? This article has an overview of such projects: https://www.railwaypro.com/wp/hanover-wurzburg-high-speed-line-completely-renovated/ Should they do overhauls without closures (is that possible?) or should they schedule them differently?
The Shinkansen doesn’t do closures for overhauls, and I think neither do LGVs. In both cases it’s considered a serious constraint – one of the benefits JR Central cites for the Chuo Shinkansen is that it can finally close Tokaido for an overhaul. In the Spinetta report, a comparison of SNCF to DB showed that DB has lower maintenance costs, which could be related to this, but could also be higher efficiency (switch installation costs seem higher in France than here and maybe that’s related) or German deferral of maintenance – the report unfortunately doesn’t investigate this difference or even remarks on it as something SNCF could improve.
The issue with the overhaul closures is that every summer, some part of the network is shut for maintenance. It’s not the same part every time, just as, on weekends, it’s not the same line in New York that’s being closed, but it always interferes with travel plans, which can use any part of the network.
OK, so we’re talking overhauls, not regular maintenance. (The post uses the term “maintenance” throughout.)
I still think we need to understand better DB’s closure strategy. Has this always been their approach? Is the current flurry of closures just the result of decades of deferral or bunching because lines of a similar age need an overhaul around the same time? What are the trade-offs for different strategies, e.g., closures vs. night-time construction over very long periods? How do they plan which lines to close in which order? Would it be possible to parallelize more construction or would more closures at the same time exacerbate the problems?
Night traffic indeed shouldn’t be an excuse against night-time construction as that would always be much less disruptive than day-time closures. Night trains anyway run much slower, so diversions are much less of a problem.
The joke I heard was something like ”Wenn du deutsche Eisenbahn Pünktlichkeit willst, gehe in die Schweiz” (If you want german punctuality for trains, go to Switzerland). At least in Baden-Württemberg, people are aware that Germany is not on top.