How Fast is Necessary?
Swiss intercity rail planning follows the maxim “run as fast as necessary, not as fast as possible.” This is usually uttered in opposition to high-speed rail in the sense of the French TGV network. But what does this slogan really mean? And how does it inform good planning?
The issue of timed connections
The origin of the Swiss planning system is in the 1970s and 80s, as it was refining intercity rail, taking what West Germany was doing with its InterCity brand and going further. Two key elements were present from the start: timed connections, and regular clockface timetables (initially every two hours in West Germany). The clockface timetabling facilitated the timed connections, since it’s easier to figure out how to schedule a timed transfer at (say) Frankfurt if the same train moves happen at the same intervals.
With these elements in place, Swiss Federal Railways (SBB) set up a schedule in which trains would be timed to arrive in Zurich all at the same time, currently just before the hour, and depart all at the same time, currently on or just after the hour.
The issue is what to do at stations other than Zurich. Optimizing for timed connections at Zurich means compromising on the question of what to do at other cities. If trains arrive and depart Zurich roughly on the hour, then the terminal at the other end may have ugly arrival and departure times – for example, a 1:40 trip time, with Zurich arrival :56 and departure :04, would mean that the other end has an arrival time of :44 and a departure time of :16. If it’s an hourly train, it means it’s not possible to time connections there – an arriving bus or regional train would have a transfer time of perhaps 20 minutes, which in a country the size of Switzerland is a large share of the overall trip.
And then there is the looming issue of intercity connections. Zurich is located fairly centrally in Switzerland, but there are some key connections that don’t go anywhere near it, led by Bern-Basel via Olten. Bern’s central location makes it a great node for timed connections as well. However, the Zurich-Bern trips took 1:09, making it impossible to have timed everywhere-to-everywhere connections in both cities.
Speeding up trains to make connections
In the 1980s, the Zurich-Bern trips took 1:09, so connections could only be timed in Zurich, not Bern. At the time, there were plans for a French-style high-speed rail network connecting Zurich, Bern, and Geneva, but those plans were canceled due to high costs relative to Switzerland’s size.
Instead of running as fast as possible, enough to connect Zurich and Geneva in perhaps 1:30, trains would run as fast as necessary, just enough to make connections. The centerpiece of this plan, dubbed Rail 2000, was to speed up Olten-Bern by just enough to shorten Zurich-Bern and Basel-Bern to 0:56 and 0:55 respectively. This way, trains could arrive in all three cities just before the hour and depart just after, facilitating more timed connections.
This system was a resounding success. Swiss rail ridership has been sharply rising in the last 20 years, from an already fairly high level; by all metrics I am aware of, such as modal split, ridership per capita, and passenger-km per capita, it is Europe’s strongest rail network. More speedups are planned, all aiming to add more points where trains can be timed to connect, called knots, till the network looks like this:

The shape of Switzerland
The notion of running trains as fast as necessary is in one sense a global principle. But its surface manifestation of a system designed as an alternative to high-speed rail is a product of Swiss geography; in Japan, the current speed of the Shinkansen is also as fast as necessary. Switzerland’s current knot diagram has to be understood in the context of the following geographical features:
- Switzerland is small enough that the strongest trunk corridors, like Zurich-Bern, can support just a train every half hour.
- Switzerland is also physically small enough that the Zurich-Bern-Basel triangle has legs of about 110 km, which an upgraded rail system can connect in an hour minus transfer time, and which it is very hard to speed up to 30 minutes minus transfer time.
- Switzerland is two-dimensional: there is no central trunk through which all service must pass – the diagram above depicts Zurich-Olten as a key link, but Luzern, though not yet a knot, connects separately to both Zurich and Bern.
- Swiss train stations have a surplus of tracks, while still functioning as central stations, without the separation into different stations for different directions that Paris and London have.
Switzerland is not unique in having these features. The Netherlands is the same: it’s a small two-dimensional country with demand for many connections to be timed. The Netherlands built a 300 km/h high-speed rail line between Amsterdam, Rotterdam, and the border with Belgium toward Antwerp, Brussels, and Paris, but this line is not important to its intercity rail planning, which instead lives on Swiss-style knots.
However, not even all small countries are like Switzerland and the Netherlands. Israel is one- rather than two-dimensional: all trains pass through Tel Aviv and the Ayalon Railway, and there is no real need for timed connections, as the most important city pair not involving Tel Aviv, Haifa-Jerusalem, passes through Tel Aviv, with through-service to begin as soon as electrification is completed. Taiwan is so linear that a single high-speed rail line connects all of its cities, with higher ridership per capita than in any other country I have data for except maybe Japan; even before high-speed rail, the shape of its mainline network was a single line on the west coast connecting the cities and another on the east coast connecting smaller settlements.
And then in large countries, running as fast as necessary requires choosing a speed. Germany is two-dimensional like Switzerland, but has a string of city pairs 90-100 km apart – Hanover-Bielefeld-Dortmund, or Mannheim-Stuttgart, or the Fulda-Frankfurt-Würzburg triangle, or Würzburg-Nuremberg – for which running a fast as necessary entails a choice between connections in 60, 45, or 30 minutes. Longer-distance city pairs, like Nuremberg-Munich, Berlin-Leipzig, and the Hamburg-Hanover-Bremen triangle, are even less constrained.
Capacity
The Swiss network is based on the idea that near major stations like Zurich, trains should arrive and depart on pulses every 30 minutes. This way, the Olten-Bern line runs eight intercity trains per hour, but they are not equally spaced: they are timetabled in two platoons over a period of seven minutes each, with the off time used for regional trains not participating in the knot system.
Even in the Netherlands, this isn’t quite tenable. Amsterdam-Eindhoven trains come at regular 10-minute interval, each third train requiring a connection at Utrecht and the other two trains in three running directly. In Israel, Tel Aviv-Haifa trains run at 30-minute intervals midday, but for two four-hour peak periods each day this is boosted to four trains per hour – and this is even before electrification has been completed.
The situation in Germany deserves especial mention. Germany is investing in it intercity rail network in a way that sometimes tries to be Switzerland except bigger (such as the Deutschlandtakt and other measures supported by technical advocates) and sometimes tries to build high-speed rail lines and through-stations like Stuttgart 21. The technical advocates dislike Stuttgart 21 and argue that it’s un-Swiss to timetable intercity trains throughout the hour rather than in two pulses with inactivity between them. But Germany has large enough cities that it can’t afford to keep intercity lines out for so much time. Already, with mediocre speeds, the Deutschlandtakt plan for 2030 prescribes 4.5 trains an hour between Frankfurt and Mannheim and between Frankfurt and Cologne. As more high-speed lines come online, demand will grow; Deutsche Bahn projects to double ridership between 2019 and the 2030s, which will force the busiest links to operate a train every five to 10 minutes.
Is Swiss planning useful outside Switzerland and the Netherlands?
Unambiguously, yes. However, it would look different.
The best place to see how different it should be is, naturally, the Northeastern United States, my area of research. None of the features that made Rail 2000 work is present there: the region is large and has huge cities, is one- rather than two-dimensional, and has capacity-constrained stations forcing round-the-hour use of every approach track.
What this means is that there is little optimization from running slower than as fast as possible on the Northeast Corridor trunk line. However, running a fast as necessary remains a solid planning maxim on all the branches that connect to it, with their own timed connections to one another and to local buses in secondary cities like Worcester and Springfield. Most trains between Boston and Washington should run as express as practical based on station track speeds, and the local trains may plausibly only run every half hour, making them ideal for a system of timed half-hourly connections.

