Around the world, large and increasing passenger volumes in major urban areas led to the upgrade of commuter rail services into a form of rapid transit. In Germany, these are called S-Bahn (for Schnell-Bahn = rapid rail), and the concept usually involves:
- separate (dedicated) tracks on at least part of the network;
- services that run across rather than into the city centre (connection of two commuter services);
- more frequent stations,
- elevated platforms for level entrance;
- specialised trains with high acceleration and lots of doors;
- frequent services at regular intervals ("clock-face schedule");
- fare integration with other public transport.
Launched in 1978, S-Bahn Stuttgart was not at all the first in Germany (that distinction belongs to Berlin's), but it is one of the better-developed ones. The city of 613,000 has a terminus station, thus the S-Bahn got a south-west to north-east tunnel running across the city, which serves as a central artery. The network is still expanding, the next two additions (dashed on map below) will close gaps this December.
The Stuttgart S-Bahn will be further enhanced in the course of the contentious Stuttgart 21 project: new tunnels into the new underground through station (which shall replace the surface terminus) will create a second S-Bahn central artery along an axis perpendicular to the existing one, and there will be new extensions towards the south and east. A lot of the criticisms of the project circle around the co-use of tunnels by the S-Bahn and long-distance trains, though.
Started in 2003, the other S-Bahn in Baden-Württemberg is the second-newest in Germany (after Bremen's system): the S-Bahn RheinNeckar, which is centered on the conurbation of Mannheim (population: 315,000) and Ludwigshafen (across the Rhine in neighbouring Rhineland-Palatinate state, population: 165,000) and includes university city Heidelberg (population: 150,000). This system needed no new lines, but the bridge across the Rhine between Ludwigshafen and Mannheim was doubled.
Both of these S-Bahn systems are still operated by former state monopolist German Railways (DB). What's noteworthy about them is that in recent times, both got specialised rolling stock, tailored for local demands, with special attention to quality and reliability issues (DB's big rolling stock orders at the end of the nineties suffered from several teething problems).
Since 2004, a third proper S-Bahn extends into Baden-Württemberg, and that across the Schengen border: a pair of branchlines at the foot of the Black Forest were absorbed by the network of Swiss city Basel, which is operated by Swiss Federal Railways SBB. Another Swiss city near the border, Schaffhausen, is getting an S-Bahn system with lines across the border after a successful referendum on its financing in 2011.
The Stadtbahn (= city rail) system was a unique development of post-war West Germany, though similar systems later became popular across the world (the most often used generic term is "light metro"). The basic idea is to upgrade tram (light rail) systems with some characteristics of metros (underground sections, at least partial separated right-of-way on the surface) and S-Bahn systems (elevated platforms in suburbs and exurbs, powerful and fast vehicles).
The full set of Stadtbahn standards were developed (and the name itself adopted) only by the 1970s, but the basic idea was pioneered by Stuttgart: in 1961, the city decided to put the entire downtown network of its narrow-gauge tram system into tunnels (suitable for an eventual conversion into heavy metro) and give the rest a separate right-of-way. The first tunnel section opened in 1966, altogether 26 km has been built until 2011. (For the record: Cologne was first to plan a tram tunnel in 1956, but that wasn't yet part of a complete network reconstruction plan and the tunnel was completed later. Outside Germany, Boston opened the Tremont Street Subway for streetcars in 1897 already; while Stockholm opened its first tram tunnel in 1933 but converted the entire network into heavy metro from 1950.)
In 1976, Stuttgart decided to go for a normal-gauge light rail system with floor-level platforms and new trams, that is a proper Stadtbahn, instead of direct conversion to a heavy metro. The first re-gauged line opened in 1985, and the work was completed in December 2011. The current network length is 128 km. Extensions to one line are in construction. An oddity of Stadtbahn Stuttgart is the use of the symbol "U", which doesn't stand for U-Bahn (subway) like everywhere else, but for unabhängig (independent [of road traffic]).
|Network map of the Stadtbahn system of Stuttgart from UrbanRail.Net. Blue and orange are the two perpendicular sub-systems of the Stadtbahn (with tunnel sections as thick lines), green is the overlaid S-Bahn network, grey is other heavy rail|
The tram systems of Mannheim, Ludwigshafen, two overland tram companies and (in part) Heidelberg, all of which are of metre gauge, have been mostly upgraded to Stadtbahn standard and linked up into a single system in stages from 1969. The Stadtbahn idea was originally not unrelated to the car city ideal (trams in tunnels rather than on the surface leave more road to cars). In downtown Mannheim however, the trams run along two main streets where cars were banned in 1974 and 1977 – at the time, such a pedestrian street solution counted as a pioneering experiment.
|Network map of the integrated Stadtbahn/light rail system of Mannheim, Ludwigshafen and Heidelberg from UrbanRail.Net. Grey is heavy rail (also used by the overlaid S-Bahn system)|
The Karlsruhe model
The standard Stadtbahn concept is not the only possible way to upgrade a tram system: another is the tram-train idea, which was pioneered in a system centred on the city of Karlsruhe (population: 297,000). The model wasn't a singular idea but developed organically:
- First the city got possession of a branchline to Bad Herrenalb, which it completely rebuilt and connected to Karlsruhe's tram system (in 1957-1966) and operated via a subsidiary called Albtal Verkehrs-Gesellschaft (AVG). At this stage, it was no more than a Stadtbahn-style line getting unusually far from the city core.
- From 1975, more lines were upgraded to Stadtbahn standard.
- From 1979, AVG started to co-use a section of a (diesel-operated) branchline owned by DB, after installing the DC catenary system of the trams along the section. For this, the co-use of a line by light trams and standard freight trains had to be solved from a train safety viewpoint. But this created the possibility to expand a Stadtbahn-style system without having to build separate own track at high cost.
- In 1992, AVG got to co-use another DB line which was already electrified with DB's AC system. Trials started in 1985 already: this innovation needed new dual-voltage vehicles with a (for trams) high top speed (100 km/h). This innovation not only resulted in more possibilities for track co-use, but the possibility to run much longer distances.
- The final innovation was to build tram tracks in the smaller cities and larger towns reached via DB tracks, first implemented on the 1997 extension to Wörth (across the Rhine in Rhineland-Palatinate state; population: 17,000).
The Karlsruhe model resulted in explosive ridership growth on all lines absorbed, and a 411 km rail transit network that is the longest in the state (in fact only surpassed in all of Germany by the Rhine-Ruhr Area and Munich S-Bahn systems). Furthermore, this network is multi-centre: for example, the first AC-electrified line now extends almost 100 km from Karlsruhe to the north-east, crossing Heilbronn (65 km from Karlsruhe, population: 124,000), where further lines in a perpendicular direction are in construction or planned. In Karsruhe itself, to deal with the new-found "tram congestion", the first tunnel sections
are in construction below the main shopping street and a perpendicular main street (they open in 2017).
|Stadtbahn Karlsruhe network map, adapted from larger version by Bahnfan1 and WikiNight from Wikimedia Commons. Grey: other heavy rail|
All of the aforementioned rail transit systems are electrified, and their expansion also meant that several formerly non-electrified rail lines got overhead lines. Since the Stuttgart, RheinNeckar and Karsruhe networks grew until they linked up, electrification reached Swiss proportions in the north of Baden-Württemberg, without a central program for 100% electrification.
|Baden-Württemberg's rail network, adapted from Thorsten Büker's rail map site. Electrified lines are in red (normal heavy rail AC electrification), purple or light red (light rail DC electrification), diesel lines in green, projected lines in grey, multi-tracked sections in thick|
More is to come, even in the less developed south and south-east of the state:
- The first section of the line along the Swiss border from Basel to Schaffhausen was awarded in August. This project also serves the expansion of the commuter networks of the two Swiss cities at both ends.
- The electrification of the mainline from Ulm south to Friedrichshafen and on to Lindau on Lake Constance is in the plans, too, although federal budget constraints delayed work to 2015.
- The cities and towns south of Stuttgart want to build a Karsruhe-style tram-train system that would absorb the mostly non-electrified lines around Tübingen. This project is still awaiting financing, although a benefit-cost ratio of 1.4 was calculated earlier this year.
S-Bahn systems are expensive, they need large populations to justify their construction. All but two proper S-Bahn systems in Germany are centred on urban areas with a population above half a million (and even the two East German exceptions are above 200,000).
Two smaller cities and their surroundings in Baden-Württemberg, however, thought to create S-Bahn networks on the cheap. The main cost saving was track-related: extra tracks only at choice locations and no electrification. For S-Bahn traffic, the diesel vehicles had to be high-powered, which meant the use of railcars only (no trailers, no articulated multiple units).
The first such network, the Breisgau-S-Bahn, serves the north and east of Freiburg (the first major city with a Green mayor in 2002, population: 229,000) since 1997. The second, the Ortenau-S-Bahn, centered on Offenburg (population: 59,000) and reaching Strasbourg in France, followed a year later. Both are operated by Südwestdeutsche Verkehrs-Aktiengesellschaft (SWEG), a regional rail company owned by Baden-Württemberg state.
A third such system, the 3er-Ringzug, was established in 2003 near the source of the Danube, in a region where rail lines which together form a circle connect eight urban areas with populations between 10,000 and 40,000. This one is operated by Hohenzollerische Landesbahn (HzL), a second regional rail company majority-owned by the state.
If we look even further into the countryside, Baden-Württemberg has interesting examples in that field, too. Until the nineties, a lot of branchlines could survive thanks to three regional rail companies: SWEG and HzL, which featured in the previous section; and Württembergische Eisenbahn-Gesellschaft (WEG), currently a subsidiary of Veolia. Then from the nineties, a number of branchlines in the state have been modernised extensively, including ones which have been without passenger or even freight service for years or even decades.
In my Local Rail diary, I presented the Schönbuchbahn line south of Stuttgart, which outdid optimistic ridership forecasts of 2,500 a day several times over (at present 8,000 a day), as the best example of how to re-launch passenger traffic on branch-lines. In addition to local involvement (support from local government and citizen initiatives) and thorough modernisation (tracks, stations, trains), the key factor behind the success was total coordination: school and office hours were adjusted to the clockface train schedule, and bus lines were re-aligned as feeders. However, the Schönbuchbahn is only the most spectacular success among half a dozen branchline re-activations for passenger service in Baden-Württemberg.
|A selection of re-activated lines in Baden-Württemberg's rail network, with year of the re-start of passenger services and the operator. (Re-activations as part of S-Bahn etc. systems not highlighted.) Again adapted from Thorsten Büker's rail map site|
Of the other examples, I now pick the Wieslauftalbahn. Only part of the line survived into the nineties, and with only 1,125 passengers a day, DB wanted to end passenger services even on the rest. Instead, a local initiative took over and modernised the section, and tasked WEG with train services from 1995. Traffic is now about 5,000 passengers a day. By 2010, the closed section, a steep mountain climb with viaducts, was rebuilt for tourist trains.
Victims of their own success
Solutions on the cheap are prone to hitting limits. Of the aforementioned non-electrified systems, both Breisgau-S-Bahn and Schönbuchbahn generated such ridership growth that three coupled railcars every half an hour is not enough in rush hour traffic. This calls for upgrades.
The Schönbuchbahn owners decided to electrify and partially double-track the line by 2016 (they are currently awaiting the state's decision on a financial contribution). Freiburg for its part adopted the "Breisgau-S-Bahn 2020" strategy, which will integrate the existing Breisgau-S-Bahn and other lines into the city into a coherent proper S-Bahn system. On the infrastructure side, the plan involves complete electrification and more double-tracked sections.
The good thing about these victims of their own success is that they created public support for upgrades with budgets that are the multiples of the original penny-wise projects.
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