The S-train is a type of hybrid urban-suburban rail serving a metropolitan region. Some of the larger S-train systems provide service similar to rapid transit systems, while smaller ones often resemble commuter or even regional rail. They are especially common in Germany and Austria, where they are known as S-Bahn, which in the 1930s was an abbreviation of either Schnellbahn, Stadtbahn or Stadtschnellbahn, depending on the city, but they must not be confused with U-Stadtbahnen. Similar S-train systems exist also in Switzerland known as S-Bahn as well. In Denmark, they are known as S-tog ['es?tsw], in the Czech Republic as Esko or S-lines, and northern Italy as Servizio ferroviario followed by either the word "metropolitano" (in Turin) or "suburbano" (in Milan).
There is no complete definition of an S-train system. S-trains are, where they exist, the most local type of railway stopping at all existing stations inside and around a city, while other mainline trains only call at major stations. They are slower than mainline railways but usually serve as fast crosstown services within the city. The Copenhagen S-tog for example goes up to 75 miles per hour (121 km/h), faster than most urban heavy rail and mass transit. S-trains generally service the hinterland of a certain city, rather than connecting different cities, although in high population density areas a few exceptions from this exist. A good example of such an exception is the Rhine-Ruhr S-Bahn, which interconnects the cities, towns and suburbs of the Ruhr, a large urban agglomeration, not unlike the large network of regional trains which also serve the area. Most S-train systems are entirely built on older local railways, or in some cases parallel to an existing dual track railway. Most use existing local mainline railway trackage, but a few branches and lines can be purpose-built S-train lines. S-trains typically use overhead lines or a third rail for traction power. In Hamburg the S-trains use both the methods, depending on which line is powered.
In smaller S-train systems and suburban sections of larger ones, S-trains typically share tracks with other rail traffic, with the Berlin S-Bahn, Hamburg S-Bahn and Copenhagen S-train being notable exceptions. Busy S-train corridors sometimes have sections of exclusive trackage of their own but parallel to mainline railways. Many of the larger S-train systems will also have central corridors of exclusive trackage that individual suburban branches feed into, creating a high frequency trunk corridor. In many cases, the central corridor is a dedicated underground line in the city centre with close stop spacing and a high frequency, similar to metro systems, created from the combined interlining of the multiple branches. A good example of this is the Berliner Stadtbahn in the Berlin's S-Bahn, which is regarded as a tourist attraction. However, in more lightly used sections outside the city centre, S-trains commonly share tracks with other train types.
Further out from the central parts of a city the individual services branch off into lines where the distances between stations can exceed 5 km, similar to commuter rail. This allows the S-train to serve a dual transport purpose: local transport within a city centre and suburban transport between central boroughs of larger cities, and to suburbs. Frequencies vary wildly between systems with short headways in the core sections of large networks to headways of over 20 minutes in remote sections of the network, late at night and/or on Sundays and in smaller systems. The rolling stock typically used in S-trains reflect its hybrid purpose. The interior is designed for short journeys with provision for standing passengers but may have more space allocated to larger and more numerous seats. Integration with other local transport for ticketing, connectivity and easy interchange between lines or other system like metros is typical for S-trains. Where both S-train and metro exist, the number of interchange stations between the two systems is substantial with metro tickets being valid on S-trains, and vice versa. The S-Bahn Mitteldeutschland constitutes the main local railway system for Leipzig but also connects to Halle, where a few stations are located. The Rostock S-Bahn is an example of a smaller S-Bahn system.
The name S-Bahn (S-train) is an abbreviation for the German "Stadtschnellbahn" (meaning "city rapid railway") and was introduced in December 1930 in Berlin. The name was introduced at the time of the reconstruction of the suburban commuter train tracks— the first section to be electrified was a section of the Berlin-Szczecin railway from Berlin Nordbahnhof to Bernau bei Berlin station in 1924, leading to the formation of the Berlin S-Bahn.
The main line Berlin Stadtbahn (English: City railway of Berlin) was electrified with a 750 volt third rail in 1928 (some steam trains ran until 1929) and the circle line Berlin Ringbahn was electrified in 1929. The electrification continued on the radial suburban railway tracks along with changing the timetable of the train system into a rapid transit model with no more than 20 minutes headway per line where a number of lines overlapped on the main line. The system peaked during the 1936 Summer Olympics in Berlin to a train schedule below 2 minutes.
The idea of heavy rail rapid transit was not unique to Berlin. Hamburg had an electric railway between the central station ("Hauptbahnhof") and Altona which opened in 1906 and in 1934 the system adopted the S-Bahn label from Berlin. The same year in Denmark, Copenhagen's S-tog opened its first line. In Austria, Vienna had its Stadtbahn main line electrified in 1908 and also introduced the term Schnellbahn ("rapid railway") in 1954 for its planned commuter railway network (which started operations in 1962). The S-Bahn label was sometimes used as well, but the name was only switched to S-Bahn Wien in 2005. As for Munich, a first breaking ground for an S-train-like rapid transport system, executed by the Nazi government of Adolf Hitler, took place in 1938 in Lindwurmstrasse near what is now Goetheplatz underground station (line U6). Said system was supposed to run through tunnels in downtown areas. The planning process mainly consisted of the bundling and interconnecting of existing suburban and local railways, plus the construction of a few new lines. Plans and construction work - including the building shell of Goetheplatz station - came to a very early halt during World War II and were not pursued in its aftermath. Very extensive nowadays, Munich's existing S-Bahn-System, together with the first two U-Bahn lines, began to operate prior to the 1972 Summer Olympics only.
The term S-Bahn was until 14 March 2012 a registered wordmark of Deutsche Bahn, where at the request of a transportation association the Federal Patent Court of Germany ordered the wordmark to be removed from the records of the German Patent and Trade Mark Office. Prior to the said event Deutsche Bahn collected a royalty of 0.4 cents per train kilometer for the usage of the said term.
The "S" stood for "station". Just before the opening of the first line in the Copenhagen S-train network, the newspaper Politiken on 17 February 1934 held a competition about the name, which in Danish became known as Den elektriske enquete or "The electrical survey" (as the Copenhagen S-trains would become the first electrical railways in Denmark). But since an "S" already was put up at all the stations, weeks before the survey, the result became S-tog which means "S-train". This was also just a few years after the S-trains had opened in Berlin and Hamburg. Today the Copenhagen S-trains uses six lines and serves 85 stations, 32 of them are located inside the (quite tiny) municipality borders. Each line uses 6 t.p.h (trains per hour) in each direction, with exception of the (yellow) F-line. The F-line have departures in each direction every five minutes, or 12 t.p.h. service .
In 1882, the growing number of steam-powered trains around Berlin prompted the Prussian State Railway to construct separate rail tracks for suburban traffic. The Berliner Stadtbahn connected Berlin's eight intercity rail stations which were spread throughout the city (all but the Stettiner Bahnhof which today is a pure S-train station known as Berlin Nordbahnhof; as the city Stettin today is Polish city Szczecin). A lower rate[clarification needed] for the newly founded Berliner Stadt-, Ring- und Vorortbahn (Berlin City, Circular and Suburban Rail) was introduced on 1 October 1891. This rate and the growing succession of trains made the short-distance service stand out from other railways.
The second suburban railway was the Hamburg-Altonaer Stadt- und Vorortbahn connecting Hamburg with Altona and Blankenese. The Altona office of the Prussian State Railway established the electric powered railway in 1906.
The beginning of the 20th century saw the first electric trains, which in Germany operated at 15,000 V on overhead lines. The Berliner Stadt-, Ring- und Vorortbahn instead implemented direct current multiple units running on 750 V from a third rail. In 1924, the first electrified route went into service. The third rail was chosen because it made both the modifications of the rail tracks (especially in tunnels and under bridges) and the side-by-side use of electric and steam trains easier.
To set it apart from the subterranean U-Bahn, the term S-Bahn replaced Stadt-, Ring- und Vorortbahn in 1930.
The Hamburg service had established an alternating current line in 1907 with the use of multiple units with slam doors. In 1940 a new system with 1200 V DC third rail and modern electric multiple units with sliding doors was integrated on this line (on the same tracks). The old system with overhead wire remained up to 1955. The other lines of the network still used steam and later Diesel power. In 1934, the Hamburg-Altonaer Stadt- und Vorortbahn was renamed as S-Bahn.
The Sydney Trains suburban rail network consists of nine lines converging in the underground City Circle with frequencies as high as three minutes in this section, 5-10 minutes at most major stations all day and 15 minutes at most minor stations all day.
Melbourne's rail network features sixteen electrified commuter rail lines traversing the city centre in the underground City Loop providing a metro-like service in the central core. A second underground core is under construction, as the Metro Tunnel project.
Commuter rail services in Brisbane are provided under the Queensland Rail City network brand, featuring twelve electrified lines converging in the city centre. Cross River Rail is an under construction underground cross-city tunnel to relieve pressure on this network.
The oldest and largest S-Bahn system in Austria is the Vienna S-Bahn, which predominantly uses non exclusive rails tracks outside of Vienna. It was established in 1962, although it was usually referred to as Schnellbahn until 2005. The white "S" on a blue circle used as the logo is said to reflect the layout of the central railway line in Vienna. However, it has now been changed for a more stylized version that is used all through Austria, except Salzburg. The rolling stock was blue for a long time, reflecting the logo colour, but red is used uniformly for nearly all local traffic today.
In 2004, the Salzburg S-Bahn went into service as the first Euroregion S-Bahn, crossing the border to the neighbouring towns of Freilassing and Berchtesgaden in Bavaria. The network is served by three corporations: the Berchtesgadener Land Bahn (BLB)(S4), the Austrian Federal Railways (German: Österreichischen Bundesbahn / ÖBB)(S2 and S3) and the Salzburger Lokalbahn (SLB)(S1 and S11) and . The Salzburg S-Bahn logo is only different one, it is a white S on a light blue circle.
The S-Bahn Steiermark has been inaugurated in December 2007 in Styria, built to connect its capital city Graz with the rest of the metropolitan area, currently the following lines are active: S1, S11, S3, S31, S5, S51, S6, S61, S7, S8 and S9. The network is operated by three railway companies: the Graz-Köflacher Bahn (GKB) (lines: S6, S61 and S7), the ÖBB (lines: S1, S3, S5, S51, S8 and S9) and the Steiermärkische Landesbahnen (StB) (lines: S11 and S31).
In December 2007 as well the Tyrol S-Bahn opened, running from Hall in Tirol in the east to Innsbruck Central Station and Telfs in the west and from Innsbruck to Steinach am Brenner. Class 4024 EMUs are used as rolling stock on this network.
The youngest network is the S-Bahn Oberösterreich in the Greater Linz area of the state of Upper Austria, which was inaugurated in December 2016. It is a 5 line system operated by Stern und Hafferl and the ÖBB.
The suburban railways of Brussels are currently being integrated into the Brussels Regional Express Network (French: Réseau Express Régional Bruxellois, RER; Dutch: Gewestelijk ExpresNet, GEN), which is identified by the letter S across both languages. In 2018, the S-train was also introduced in Antwerp, Ghent, Liège and Charleroi.
Toronto's GO Transit is in the process of transforming its network to an S-train like system. GO Regional Express Rail (GO RER) will electrify 5 of the 7 core GO lines as well as the Union Pearson Express (UPX). Planned frequencies are all-day, two-way 15 minute or better service in both directions in Toronto and its suburbs. Trains from each line are already through-routed via Union Station. A new fleet of EMUs and electric locomotives will also be procured. The bidder is expected to be announced in 2021. Electrification on the 5 GO Lines is to commence in 2022.
In the Czech Republic, integrated commuter rail systems exist in Prague and Moravian-Silesian Region. Both systems are called Esko, which is how S letter is usually called in Czech. Esko Prague has been operating since 9 December 2007 as a part of the Prague Integrated Transport system. Esko Moravian-Silesian Region began operating on 14 December 2008 as a part of the ODIS Integrated Transport system serving the Moravian-Silesian Region. Both systems are primarily operated by ?eské dráhy. Several shorter lines are operated by other companies.
Copenhagen S-train connects the city centre, other inner and outer boroughs and suburbs with each other. The average distance between stations is 2.0 km, shorter in the city core and inner boroughs, longer at the end of lines that serve suburbs. Of the 85 stations, 32 are located within the central parts of the city. Some stations are located around 40 km from Copenhagen city centre. For this reason the fares vary depending on distances. One-day-passes which tourist buy are valid only in the most central parts of the S-train system. Weekdays each line have departures every 10th minute with exception for the F-line, which departures every fifth minute. Where several lines use the same branches, up to around 30 trains per hour (in each direction) service exists. On Sundays the seven lines are reduced to four lines, but all stations are served at least every 10th minute. The three railway stations at Amager have a local service that equals the S-trains'.
The Copenhagen Metro opened in 2002 as a complement to the already existing S-train system. Copenhagen's S-train system is the only one in the country. Outside Denmark, in cities where both exist, is it far from unusual that a metro system later has been complemented with S-trains. The branch towards Køge (the southernmost S-train station in Copenhagen's S-network) has a rather unique history, as it was built in the 1970s where no previous railway ever had existed.
The term Réseau Express Régional (lit. Regional Express Network) originally meant the Paris system, but is now used for other French networks as well. However, only the Paris RER has high freqency underground corridors where several suburban branches feed and stop spacing of a rapid transit system similar to an S-Train.
The trains of the Berlin and Hamburg S-Bahn systems ran on separate tracks from the beginning. When other cities started implementing their systems in the 1960s, they mostly had to use the existing intercity rail tracks, and they still more or less use such tracks.
The central intercity stations of Frankfurt, Leipzig, Munich and Stuttgart are terminal stations, so all four cities have monocentric S-Bahn networks. The S-Bahn trains use a tunnel under the central station and the city centre.
The high number of large cities in the Ruhr area promotes a polycentric network connecting all cities and suburbs. The S-Bahn Rhein-Ruhr, as it is called, features few tunnels, and its routes are longer than those of other networks. The Ruhr S-Bahn is the only S-Bahn network to be run by more than one corporation in Germany, and the Salzburg S-Bahn holds a similar distinction in Austria. Most Swiss S-Bahn systems are multi-corporation networks, however.
Most German S-Bahn networks have a unique ticket system, separated from the Deutsche Bahn rates, instead connected to the city ticket system used for U-bahns and local busses. The S-Bahn of Hanover, however, operates under five different rates due to its large expanse.
One S-Bahn system is no longer in operation: the Erfurt S-Bahn which operated from 1976 until 1993 and was an 8.6 km (5.3 mi) single-line system which consisted of four stations from Erfurt Central Station to Erfurt Berliner Straße station in the then newly built northern suburbs of Erfurt.
The following networks are currently in operation:
|S-Bahn||Area of Responsibility||Authority||Opened||Lines||Kilometrage||Rolling Stock||Company||Expiry of contract|
|Berlin S-Bahn||Berlin, Potsdam||VBB||1924||16||331 km||480, 481, 485||S-Bahn Berlin GmbH||2017|
|Breisgau-S-Bahn||Freiburg im Breisgau||RVF||1997[A]||7||50 km||Alstom Coradia Continental, Stadler Regio-Shuttle RS1||DB Regio AG (electric), SWEG (diesel)|
|Bremen S-Bahn||Bremen, Bremerhaven, Oldenburg||VBN||2010||4||270 km||Alstom Coradia Continental||NordWestBahn||2021|
|Dresden S-Bahn||Dresden||VVO||1992||3||128 km||143 + Doppelstockwagen, 146.0 + Doppelstockwagen||DB Regio Südost||2027|
|Hamburg S-Bahn||Hamburg||HVV||1934||6||144 km||472, 474, 490||DB Regio AG||2033|
|Hannover S-Bahn||Hannover, Paderborn, Hildesheim, Minden||GVH, nph||2000||9 (+ 1)||385 km||424, 425||DB Regio Nord||2020|
|Mitteldeutschland S-Bahn||Leipzig, , Zwickau, Bitterfeld, Wurzen, Borna||MDV, VBB, VMS, VVO||2013||10||802 km||Bombardier Talent 2, 143 + Doppelstockwagen||DB Regio Südost||2025/2030|
|Mittelelbe S-Bahn||Magdeburg||marego||1974||1||130 km||425||DB Regio Südost||2028|
|Munich S-Bahn||Munich and surrounding counties||MVV||1972||8||434 km||423, 420||DB Regio AG||2017|
|Nürnberg S-Bahn||Nürnberg, Bamberg||VGN||1987||4||227 km||143 + x-Wagen, Bombardier Talent 2||DB Regio Bayern||2030|
|Ortenau-S-Bahn||Offenburg, Straßburg||TGO||1998||4||170 km||Stadler Regio-Shuttle RS1||SWEG|
|Rhine-Main S-Bahn||Frankfurt am Main, Wiesbaden, Mainz, Darmstadt, Offenbach am Main||RMV||1978||9||303 km||423, 430||DB Regio AG||2029,|
|RheinNeckar S-Bahn||Mannheim, Karlsruhe, Ludwigshafen am Rhein, Heidelberg, Kaiserslautern||VRN, KVV, HNV, saarVV||2003||7||370 km||425||DB Regio Südwest||2017,|
|Ruhrgebiet (esp. Duisburg, Essen, Bochum, Dortmund, Düsseldorf, Wuppertal)
Rheinland (Köln, Bonn)
|14||717 km||143 + x-Wagen, 420, 422, 423, Bombardier Talent, Alstom Coradia LINT, Alstom Coradia Continental||DB Regio NRW, Regiobahn, Abellio Rail NRW|
|Rostock S-Bahn||Rostock||VVW||1974||3||91 km||Bombardier Talent 2||DB Regio Nordost||2024|
|Stuttgart S-Bahn||Stuttgart, Waiblingen, Esslingen, Ludwigsburg, Böblingen||VVS||1978||7||215 km||423, 430||DB Regio AG||2028|
There are three Proastiakos networks, servicing the country's three largest cities: Athens, Thessaloniki and Patras, providing them with commuter rail links towards their suburbs and also with regional services to other cities and towns. In particular, the Athens network is due to undergo modifications to completely separate it from mainline traffic, such as being rerouted via a tunnel underneath the city center.
The three MTR lines which are owned and formerly operated by the Kowloon-Canton Railway Corporation (East Rail Line, West Rail Line, Ma On Shan Line, then the "KCR"), and MTR's own Tung Chung Line connect the new towns in New Territories and the city centre Kowloon together with frequent intervals, and some New Territories-bound trains terminate at intermediate stations, providing more frequent services in Kowloon and the towns closer to Kowloon. Most of the sections of the these four lines are overground and some sections of the East Rail Line share tracks with intercity trains to mainland China. The three KCR lines are integrated into the MTR network since 2008 and most passengers do not need to exit and re-enter the system through separate fare gates and purchase separate tickets to transfer between such lines and the rest of the network (the exceptions are between the West Rail Line's East Tsim Sha Tsui station and the Tsuen Wan Line's Tsim Sha Tsui station, and between the East Rail Line's Mong Kok station and the Kwun Tong Line's Mong Kok Station).
KRL Commuterline or Commuter Line Jabodetabek is a commuter railway system serving Jakarta and its satellite cities as well as its regencies. The system currently has 6 lines, 80 stations, and it spans 480 km with roughly 300 million passengers annually. The system only accept bank-issued cards and e-tickets which can be purchased or topped up at any stations throughout the system.
Dublin Suburban Rail and DART fill the role of an S-train rail service in Dublin, Ireland, although only DART has the common spine running through the city centre that characterises other European S-train networks, although this runs on an elevated track, rather than underground.
Several systems in Italy operate quite similar to S-Trains with numerous services funneling into the underground "Passante" or passing railway.
Operating services in the country are:
East Japan Railway Company operates a large suburban train network in Tokyo with various lines connecting the suburban areas to the city center. While the Yamanote Line, Keihin Tohoku Line, Ch-S?bu Line services arguably are more akin to rapid transit with frequent stops, simple stopping patterns (relative to other JR East lines) no branching services and largely serving the inner suburbs; other services along the Ch Rapid Line, S?bu Rapid Line/Yokosuka Line, Ueno-Tokyo Line, Sh?nan-Shinjuku Line etc. behave more like S-Train lines with numerous mid-distance services from the outer suburban lines through operating into these lines to form a high frequency corridor though central Tokyo; Only to branch off and interoperate with other JR East suburban lines on the other side of central Tokyo.
In addition, it is common for the numerous private railway companies to funnel train traffic into through operations with Tokyo subway lines. Where all but three of Tokyo's 13 subway lines serve as underground trunk lines for suburban rail operators to access Tokyo city center. This is a product of laws preventing private operators from constructing railways inside the Yamanote Loop Line.
Unlike Tokyo a number of underground cross city corridors were constructed by suburban operators to allow suburban trains to access the city center.
"Randstadspoor" is a network of Sprinter train services in and around the city of Utrecht, similar to S-trains. For the realisation of this network, five new stations were opened: Utrecht Zuilen, Utrecht Terwijde, Utrecht Leidsche Rijn, Utrecht Vaartsche Rijn and Houten Castellum. Extra tracks have been built to create dedicated routes for these Sprinters, so they can call frequently without disturbing high-frequent Intercity services parallel to these routes. Similar systems are planned for The Hague and Rotterdam, the latter of which already has the Rotterdam Metro network.
In Poland, three comparable systems exist, but the terms used are "Szybka Kolej Miejska" (fast urban rail) and "kolej aglomeracyjna" (agglomeration rail). These systems are:
The names "S-Bahn" and "S-Train" is not used in Russia. Officially, such a system is called an "urban electric train", or less often and unofficially "ground metro". These names are often used, even if non-electrified trains or rail buses are used as the rolling stock on the routes. The first similar project, implemented before the revolution, is the Oranienbaum Electric Line in St. Petersburg. Also, an approximate analogue was Beskudnikovskaya railway branch, which existed in Moscow between the 1940s and 1980s. The trains that shuttled along it did not go to the main lines, so it was a city transport. However the most similar to S-Train systems with frequent electric trains in Russia are in Moscow. (Moscow Central Circle and Moscow Central Diameters)
BG Voz is an urban rail system that serves Serbian capital. It is fairly similar to German S-Bahn, but currently has only two lines, with plans for further expansion. Between early 1990s and mid-2010s, there was another system, known as Beovoz, that was used to provide mass-transit service within the Belgrade metropolitan area, as well as to nearby towns, similarly to RER in Paris. Beovoz had more lines and far more stops than the current system. However, it was abandoned in favor of more accurate BG Voz, mostly due to inefficiency. While current lines rely mostly on the existing infrastructure, any further development means furthering capacities (railways expansion and new trains). Plans for further extension of system include another two lines, one of which should reach Belgrade Nikola Tesla Airport.
In Bilbao, two comparable systems operate; Cercanías Bilbao (of which lines C-1 and C-2 are mostly separate from the national rail network) and Euskotren Trena, which both feature underground sections in the city centre.
Cercanías Málaga's C-1 line from Málaga Centro-Alameda to Fuengirola features several underground sections and uses a route mostly separate from the national rail network of Spain, aside from a small section between Málaga-María Zambrano and Victoria Kent.
SL operates the Pendeltåg network in the Stockholm metro area and it is integrated into the rest of the SL network. Although most stations are at-grade or overground, Stockholm City, Stockholm Odenplan, and Stockholm South are among the stations that are underground. Travelling on most destinations reachable from Stockholm's city centre costs the same as a subway (T-bana) or local bus ride and transfer windows between a Pendeltåg and subway/local bus are free within the validity of the fare purchased. A supplement is charged for journeys involving Arlanda airport and/or Uppsala. In addition to the Pendeltåg, SL operates the Roslagsbanan commuter rail network (also denoted by a J), which runs from Stockholm East station to the eastern and northeastern portions of Stockholm County and fares cost the same as a subway or local bus ride.
S-Bahn is also used in German-speaking Switzerland. While French publications of those networks translate it as RER, the line numbers are still prefixed with an S (e. g. S2).
The oldest network in Switzerland is the Bern S-Bahn, established in stages from 1974 and has adopted the term S-Bahn since 1995. It is also the only one in Switzerland to use a coloured "S" logo. In 1990, the Zürich S-Bahn, which covers the largest area, went into service. S-Bahn services were set up in the course of the Bahn 2000 initiative in Central Switzerland (a collaborative network of S-Bahn Luzern and Stadtbahn Zug), St. Gallen (S-Bahn St. Gallen) and Ticino (Rete celere del Canton Ticino).
The Basel trinational S-Bahn services the Basel metropolitan area, thus providing cross-border transportation into both France and Germany. A tunnel connecting Basel's two large intercity stations (Basel Badischer Bahnhof and Basel SBB) is planned as Herzstück Regio-S-Bahn Basel (lit. heart-piece Regio-S-Bahn Basel).
The RER Vaud of Lausanne and the Léman Express of Geneva serve the area around Lake Geneva (fr. Lac Léman). Transborder networks for the Lake Constance-adjacent German states Baden-Württemberg and Bavaria, the Austrian state Vorarlberg and the Swiss cantons St. Gallen and Thurgau are under discussion. Possible names are Bodensee-S-Bahn and Alpenrhein-Bahn.