Munich S-Bahn


The Munich S-Bahn is an electric rail transit system in Munich, Germany. "S-Bahn" is the German abbreviation for Stadtschnellbahn, and the Munich S-Bahn exhibits characteristics of both rapid transit and commuter rail systems.
The Munich S-Bahn network is operated by S-Bahn München, a subsidiary of DB Regio Bayern that is itself a subsidiary of the German national railway. It is integrated into the Munich Transport and Tariff Association and interconnected throughout the city with the locally owned Munich U-Bahn. Today, the S-Bahn covers most of the populated area of the Munich Metropolitan area of about 2.7 million inhabitants.
The Munich S-Bahn was established on 28 May 1972. It was intended as part of the scheme to provide an adequate transport system during the 1972 Summer Olympics held in Munich by connecting the pre-existing suburban rail services in the west and east of the city via a new tunnel section from Hauptbahnhof to München Ost station.

Lines

System

The system has seven branches in the west, which were originally numbered from north to south from the S 1 to the S 7. These are coupled with the five eastern branches. Operational requirements have changed several times, particularly due to line extensions, resulting in random numbering in the east. Two lines end at Munich East station, these are currently S 1 and S 6. The first change was made in June 1991 when the branch to Ebersberg changed from S 4 to S 5 as a requirement to shorten the travel time to and from Herrsching. The line to Wolfratshausen was first called the S 10, but when it was connected to run over the trunk line it was changed to the S 7.
The S-Bahn branch in the east via Ismaning to the airport was designated as the S 8. Later this was combined with the original line S 3, which shared part the route of the S 8, and the new route is called the S 8. This eliminated route S 3. The old route S 5 was later largely replaced by the current S 3, so there is currently no line S 5.
In addition there are lines S 20 and S 27, which run from Munich Central Station and Pasing to Deisenhofen. These two lines do not run through the trunk line tunnel. The numbers beginning with 2 comes from the time of the introduction of these lines, as the line to Holzkirchen via Deisenhofen still had the number S 2. These lines cross the Isar via Großhesselohe Bridge.
In the Deutsche Bahn time table, the S-Bahn lines are numbered from 999.1 to 999.8 and 999.20; line A is numbered as 999.30.

Frequency

The basic interval of the Munich S-Bahn is one train every 20 minutes. On parts of some branches during peak hours there is a 10-minute frequency produced by added trains. A special case is the line to Erding, where on weekdays a mix of express trains from Erding and normal S-Bahn trains from Markt Schwaben runs in the morning peaks, producing a 10-minute frequency west of Munich East station. There are also occasional additional trains on the western section of the S4 and on the S1 between Freising and Munich during the peak hour, which do not continue past the Hauptbahnhof. On some branches, one of three trains does not run to the terminus station at off-peak times, so that on these outer sections trains run at 20 or 40 minutes alternatively. The S8 is 24/7.
LineRouteFrequency
Freising – Pulling – NeufahrnEvery 20 or 40 minutes alternatively
Munich Airport – Flughafen Besucherpark – Neufahrn – Eching – Lohhof – UnterschleißheimOberschleißheimFeldmoching – Fasanerie – MoosachLaimHirschgartenDonnersbergerbrückeHackerbrücke – Hauptbahnhof – Karlsplatz – MarienplatzIsartorRosenheimer PlatzOstbahnhofEvery 20 minutes
Petershausen – Vierkirchen-Esterhofen – Röhrmoos – Hebertshausen – DachauEvery 20 or 40 minutes alternatively
Altomünster – Kleinberghofen – Erdweg – Arnbach – Markt Indersdorf – Niederroth – Schwabhausen – Bachern – Dachau Stadt – DachauEvery 60 minutes,
every 30 minutes in the peak hour
Dachau – Karlsfeld – Allach – Untermenzing – Obermenzing – Laim – Hirschgarten – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – Marienplatz – Isartor – Ostbahnhof – LeuchtenbergringBerg am LaimRiem – Feldkirchen – Heimstetten – Grub – Poing – Markt SchwabenEvery 20 minutes
Markt Schwaben – Ottenhofen – St. Kolomann – Aufhausen – Altenerding – ErdingEvery 20 or 40 minutes alternatively
Mammendorf – Malching – MaisachEvery 20 or 40 minutes alternatively
Maisach – Gernlinden – Esting – Olching – Gröbenzell – Lochhausen – Langwied – Pasing – Laim – Hirschgarten – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – Marienplatz – Isartor – Rosenheimer Platz – Ostbahnhof – St.-Martin-Straße – GiesingFasangarten – Fasanenpark – Unterhaching – Taufkirchen – Furth – Deisenhofen Every 20 minutes
Deisenhofen – Sauerlach – Otterfing – HolzkirchenEvery 20 or 40 minutes alternatively
Geltendorf – Türkenfeld – Grafrath Every 20 or 40 minutes alternatively
Buchenau – Fürstenfeldbruck – Eichenau – Puchheim – Aubing – Leienfelsstraße – Pasing – Laim – Hirschgarten – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – Marienplatz – Isartor – Rosenheimer Platz – Ostbahnhof – Leuchtenbergring – Berg am Laim – TruderingEvery 20 minutes
Trudering – Gronsdorf – Haar – Vaterstetten – Baldham – Zorneding – Eglharting – Kirchseeon – Grafing stationEvery 20 minutes in the peak hours
Grafing station – Grafing Stadt – EbersbergEvery 20 or 40 minutes in the peak hours
TutzingFeldafing – Possenhofen – StarnbergEvery 20 or 40 minutes alternatively
Starnberg – Starnberg Nord – Gauting – Stockdorf – Planegg – Gräfelfing – Lochham – Westkreuz – Pasing – Laim – Hirschgarten – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – Marienplatz – Isartor – Rosenheimer Platz – Ostbahnhof – Leuchtenbergring – Berg am Laim – Trudering – Gronsdorf – Haar – Vaterstetten – Baldham – Zorneding – Eglharting – Kirchseeon – Grafing StationEvery 20 minutes
Grafing Station – Grafing Stadt – EbersbergEvery 20 minutes in the peak hour and every 20 or 40 minutes during the day
Wolfratshausen – Icking – Ebenhausen-Schäftlarn – Hohenschäftlarn – Baierbrunn – Buchenhain – HöllriegelskreuthEvery 20 or 40 minutes alternatively
Höllriegelskreuth – PullachGroßhesselohe IsartalbahnhofSollnSiemenswerkeMittersendlingHarrasHeimeranplatz – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – München Marienplatz station – Isartor – Rosenheimer Platz – Ostbahnhof – St.-Martin-Straße – Giesing – Perlach – Neuperlach Süd – Neubiberg – Ottobrunn – Hohenbrunn – Wächterhof – Höhenkirchen-SiegertsbrunnEvery 20 minutes
Höhenkirchen-Siegertsbrunn – Dürrnhaar – AyingEvery 20 or 40 minutes alternatively
Aying – Peiß – Großhelfendorf – KreuzstraßeHourly
Herrsching – Seefeld-Hechendorf – Steinebach – WeßlingEvery 20 or 40 minutes alternatively
Weßling – Neugilching – Gilching-Argelsried – Geisenbrunn – Germering-Unterpfaffenhofen – Harthaus – Neuaubing – Westkreuz – Pasing – Laim – Hirschgarten – Donnersbergerbrücke – Hackerbrücke – Hauptbahnhof – Karlsplatz – Marienplatz – Isartor – Rosenheimer Platz – Ostbahnhof – Leuchtenbergring – DaglfingEnglschalking – Johanneskirchen – Unterföhring – Ismaning – Hallbergmoos – Flughafen Besucherpark – Munich AirportEvery 20 minutes
Pasing – Heimeranplatz – Mittersendling – Siemenswerke – Solln – Großhesselohe Isartalbahnhof – Pullach – HöllriegelskreuthHourly

Terminus of extra services in peak. Up to here services in the peak run at 10-minute intervals.
Occasional additional services to create 10 minute frequency.

Routes

The S-Bahn partly operates on its own routes, parts of it are double-track lines where S-Bahn operations are mixed with other traffic, and in some cases more than two tracks are available. In the latter case one-or two tracks are set aside for the S-Bahn operations only and the two other tracks are used for the remaining traffic.
In the following table, the route length is shown from Munich Hauptbahnhof or from Ostbahnhof because it reflects the chainage officially applied to the lines. An exception is S27 where the chainage starts at Pasing.
LineRoute and
section
Distance from Hbf or OstbfOther trafficInfrastructure
to Trunk line
Pasing–Hbf–Ostbahnhof
11.4 kmBetween Pasing and Hauptbahnhof some trains are operated between Donnersbergerbrücke and Hauptbahnhof by Bayerische OberlandbahnThree stations with three or more platform tracks, three stations using Spanish solution.
WestMunich–Regensburg railway
Laim–Freising
40.7 kmRegional and Interregional services, as well as freight traffic.Two tracks in mixed operation for 34.5 km.
WestNeufahrn Link
Neufahrn–Airport West
40.8 kmS-Bahn only, except for occasional freight trainsTwo tracks.
WestMunich–Ingolstadt line
Laim–Petershausen
36.4 kmIntercity-Express services to Berlin and Hamburg as well as Frankfurt via Nuremberg, Regional services to Nuremberg and Ingolstadt and freight traffic.Separate S-Bahn in addition to high-speed tracks for ICE and other traffic.
WestDachau–Altomünster railway
Dachau–Altomünster
47.7 kmS-Bahn onlySingle track
WestMunich–Augsburg railway
Pasing–Mammendorf
31.0 kmRegional, long-distance and freight traffic. This is one of the busiest lines in Germany, so it was upgraded to four tracks for the S-Bahn.Separate tracks for the S-Bahn.
WestAllgäu Railway
Pasing–Geltendorf
42.1 kmVarious regional services every two hours, two hourly EuroCity service to Zürich, diverted long distance services from Augsburg-Munich lineTwo tracks mixed operations for 34.7 km. Electrified for the S-Bahn to Geltendorf.
West
Munich–Herrsching railway
Pasing–Herrsching
38.3 kmOnly S-Bahn services.Two tracks to Weßling, then single track.
WestMunich–Garmisch-Partenkirchen railway
Pasing–Tutzing
39.6 kmRegional services and occasional long distance trains to Garmisch-Partenkirchen.Two separate S-Bahn tracks to Gauting, then two tracks in mixed operation.
WestIsar Valley Railway
Solln–Wolfratshausen
31.3 kmOnly S-Bahn services.Two tracks to Höllriegelskreuth, then single track.
EastAirport line
Ostbahnhof–Ismaning–Airport
33.1 kmFreight traffic between Daglfing and North Ring.Continuous two tracks, some in mixed operation with freight.
EastMunich–Mühldorf railway and Markt Schwaben–Erding railway
Ostbahnhof–Markt Schwaben–Erding
34.7 kmFreight and regional traffic towards Mühldorf and Freilassing to Markt Schwaben, then only S-Bahn traffic.Two tracks in mixed operation to Markt Schwaben, then single track to Erding.
EastMunich–Rosenheim railway and Grafing–Wasserburg railway
Ostbahnhof–Grafing–Ebersberg
31.0 kmRegional services to Rosenheim and Wasserburg, long distance services to Salzburg, as well as freight traffic.Four tracks to Grafing, then single track with mixed traffic.
EastMunich East–Deisenhofen railway and Munich-Giesing–Kreuzstraße railway
Giesing–Kreuzstraße
30.1 kmS-Bahn only.Single track.
EastMunich East–Deisenhofen railway and Munich–Holzkirchen railway
Ostbahnhof–Giesing–Deisenhofen–Holzkirchen
31.2 kmS-Bahn only to Deisenhofen. The Bayerische Oberlandbahn also operates between Deisenhofen and Holzkirchen.Two tracks.
Sendling Clasp
Pasing–Mittersendling–Höllriegelskreuth
Pasing–Mittersendling–Höllriegelskreuth
20.5 kmRuns in part over freight tracks to/from Munich Laim marshalling yard and between Mittersendling and Solln over the Bayerische Oberland Bahn.Single track to Mittersendling, then continuing on double track in mixed operation.

Former Lines / Station Renamings

Here are some of the former train lines. Some of the stations are also renamed as well.
The little known connection between the Hauptbahnhof and the Ostbahnhof, called the "Südring", runs west from Hauptbahnhof before turning south and curving toward Ostbahnhof without any stops in between. The trains travelling on this route are included in the MVV tariff scheme and offer a view of the city while the travel time is slightly longer than the Stammstrecke tunnel.
Additional regional lines make calls at stations also served by the S-Bahn but provide an effective express functionality for MVV passengers. The examples include:
Expansion plans announced by the MVV on 7 April 2017 include express S-Bahn lines with limited stops operating through the second tunnel now under construction.

History

An underground railway line for Munich was first proposed in 1928 in a report on the "relocation of traffic centres". An underground route would allow "direct long distance traffic to and through the city centre".
On 22 May 1938, the first tunnel, which was part of the north-south route, was started in the Lindwurmstraße, between the present-day underground stations Sendlinger Tor and Goetheplatz. In the speech of Julius Dorpmüller, the general director of Deutsche Reichsbahn, the project was called "S-Bahn" for the first time. Due to World War II the construction and plans for the Munich S-Bahn were set aside.
FromToTunnel
SchleißheimFreisingRingbahn
DachauOst-West
MaisachOst-West
AubingGrafrathOst-West
Unterpfaffenhofen-GermeringHerrschingOst-West
GautingOst-West
Ringbahn
Luise-Kiesselbach-PlatzGroßhadernNord-Süd
HöllriegelskreuthNord-Süd
DeisenhofenBayrischzellNord-Süd
Ost-West
NeubibergKreuzstraßeOst-West
HaarGrafingOst-West
RiemMarkt SchwabenOst-West
DaglfingOst-West
FreimannNord-Süd
IsmaningNord-Süd

Plans, with the Munich Olympic bid

In 1965, the Federal Republic of Germany, the Free State of Bavaria, the state capital of Munich and the Deutsche Bundesbahn signed a contract on the construction of the Munich S-Bahn. The further development was most influenced by a decision made in Rome on 26 April 1966: the International Olympic Committee chose Munich over Detroit, Madrid and Montreal as the location for the 1972 Summer Olympics, resulting in a tight schedule of only six years to complete the Munich S-Bahn network.
LineWestEast
Plans
East
From 1972
FreisingIsmaningKreuzstraße
PetershausenErdingDeisenhofen
Nannhofen
DeisenhofenIsmaning
GeltendorfKreuzstraßeEbersberg
HerrschingMünchen OstbahnhofMünchen Ostbahnhof
TutzingEbersbergErding
WolfratshausenHauptbahnhof
Hauptbahnhof
DeisenhofenHauptbahnhof
DeisenhofenMünchen-Pasing

Not only did the tunnel through the city centre have to be built, the full railway infrastructure had to be expanded. The network of suburban lines had to be changed over and modernized. A large number of stations had to be upgraded; platforms were extended to a length of to allow for three-unit trains, and the platform height was raised to. However, the floor height of trains used then and now is at approximately, which makes boarding difficult for people with wheelchairs or prams. Tunnel stations and platforms updated recently where no freight trains run do feature a height of, however.
On 25 February 1971 the topping-out ceremony could be celebrated in the core route tunnel. In May the first S-Bahn train of the ET 420 series was put into service on the route between Pasing and Gauting. On 1 September 1971 a regular advance service was started on that route.

Opening

On 28 May 1972, the Munich S-Bahn network was finally put into service with of tracks and 101 trains of the ET 420 series. Town names in the nearby Munich such as Dachau, Tutzing, Erding and Pasing came into the picture. It was the first time a S-Bahn network that size was put into service on a single date. The route S10 to Wolfratshausen was operated with conventional push-pull trains from the southern wing of Munich Central Station. It was electrified later and connected to the core route after the construction of a tunnel crossing the large number of mainline rail tracks leading to Munich Central Station.
Three months later the German President Gustav Heinemann opened the 1972 Summer Olympics. During the Games there were two additional S-Bahn lines servicing the now-defunct station Olympiastadion. The new S-Bahn system stood the test and transported 3.18 million passengers in 7,138 runs to and from the sports sites in only 17 days. The first stage was limited by the Olympic Games in 1972. Because of the enormous time pressure, not all lines could be equipped for a 10 or 20 minute cycle.
The second stage was necessary mainly because of the increasing traffic volume. In 1973 and 1974, the Deutsche Bundesbahn established the following construction measures: Own S-Bahn tracks were to be built on the railway tracks from Lochhausen to Nannhofen and from Munich to East Grafing, So as not to hinder long-distance and regional transport on the respective routes. As new settlements developed in Esting, in the south Neuperlachs and in Unterschleißheim new settlements, the new breakpoints Unterschleißheim in the year 1977, Neuperlach Süd in 1977 and Esting in 1980. In addition, The railway line to Herrsching was to be extended two-way between Freiham and Weßling.
Since then the Munich S-Bahn network has been expanded multiple times. On 28 May 1980, it was extended to Mammendorf. On 3 November 1979, it was extended to Ebersberg. S5 was extended to Herrsching in 1984.
In 1992, the route between Ismaning and the newly opened Airport Munich II was put into service as S8, followed by S1 extension on 29 November 1998.

Further Tweaks

With the timetable change on December 12, 2004, the ten-minute cycle on the S 4 from Maisach to Zorneding and on the S 5 from Germering-Unterpfaffenhofen to Deisenhofen was introduced during rush hour, the number of train journeys has gone from three to six per Hour doubled. Since December 12, 2005 is also offered on the western section of the S 2 to Dachau a clock doubling.
In August 1998, the federal government, the Free State of Bavaria and Deutsche Bahn decided on a so-called 266-million-euro package, within which for the foreseeable future feasible projects to introduce a ten-minute cycle decided and end of 1998 to a financing agreement. The main point was the modernization of the control and safety technology between Pasing and Ostbahnhof, including the installation of a line train control. Between 2001 and 2005, construction work on the external lines continued as part of the €266 million twin track program. In addition, new S-Bahn stations were opened on 10 June 2001 in Starnberg Nord and on 11 December 2005 in Untermenzing. Some already existing stations on the outer routes could still be developed barrier-free in the financial framework of the project. On 21 November 2005, the section of the airport line S 8 in the territory of the municipality Unterföhring was moved between Johanneskirchen and Ismaning in the underground, this was at the request of the community, the new tunnel station Unterföhring. On December 13, 2009, a new breakpoint at the Hirschgarten was inaugurated at the S-Bahn trunk line between Laim and Donnersbergerbrücke.
In June, July and August 2012, the trunk line was closed on seven weekends to renew the tracks in the aboveground area. 18 of the 27 turnouts on the main line were equipped with heaters to prevent freezing in winter. In addition, the fire protection systems were renewed in some tunnel stations, around the escalators were new glass structures, which should prevent the retraction of the smoke, in the case of a fire. During the blockage, rail replacement traffic was established and the S 8 was diverted via the Südring. Due to a lack of funds not all stations could be equipped with heaters and the installation of the fire protection systems has not yet been completed, the base line closures continued in summer and autumn 2013. During this time, in particular the station Donnersbergerbrücke was modernized and barrier-free equipped with elevators. The closures began on July 22, 2013 and lasted until December 20, 2013. On six weekends in the summer, the trunk line was completely closed and a replacement rail service was set up. On the remaining weekends, commuter trains between Pasing and Ostbahnhof as well as Hackerbrücke and Ostbahnhof operate every 20 minutes. For remaining work at the station Donnersbergerbrücke took place on the weekends and in late traffic from March to June 2014 again blocked. It was set up on two weekends rail replacement traffic between Pasing and Hackerbrücke, otherwise reversed commuter train trains.
On September 14, 2013 on the line S8 the breakpoint Freiham was reopened, which is to connect the new residential area Freiham. It is located one kilometer east of the 1975 decommissioned station Freiham. Construction had begun on June 12, 2012.
On December 15, 2013, the S 27 from the main station to Deisenhofen was discontinued, the trips are taken by the half-hourly Meridian trains of the Bavarian Oberlandbahn, which are extended in the rush hour via Holzkirchen and the Mangfalltalbahn to Rosenheim. In addition, the terminus of the S 20 line was relocated from Deisenhofen to Höllriegelskreuth on the Isartalbahn. The railway line Munich-Holzkirchen is no longer served by S-Bahn trains between Solln and Deisenhofen.
In 2014, the Dachau–Altomünster railway line, which had previously been used by line A, was electrified which was the final stretch of the S-Bahn. Furthermore, a two-track meeting section between Bachern and Schwabhausen and an additional crossing station in Erdweg were built. The planning approval process was completed in January 2013. From April 28 to December 13, 2014, the line A line between Dachau and Altomünster was discontinued for line electrification, and the Class 428 railcar drives were replaced by bus replacement buses. After completion of the conversion work, the electrical operation was started on 14 December 2014. Instead of the hourly clock is now offered in the rush hour, a 30-minute cycle. The route is operated as a wing section of the S 2. The last cost estimate was 47 million euros. The construction was originally scheduled to start in 2012 and completion was scheduled for 2013.
Further dates:

Class 420

Since the opening of the S-Bahn network from 1972 to 2004, vehicles of the DB Class 420 have been used in the Munich S-Bahn network. In 1972, however, only 101 of the ordered 120 trains were available, so that on some routes until 1975 had to be driven with turning trains. The first 120 vehicles came from the first series of this series. In the following years, due to the higher demand for vehicles, about 30 vehicles of the second construction series came to Munich. The number of trains of the second series of construction varied, as they were also exchanged with vehicles from other cities. From 1979 to 1982 also came vehicles of the fifth and sixth series to Munich, these were used after 1982 but again in other suburban rail networks. From 1992, some vehicles of the seventh and from 1996 the eighth series were added, so that the vehicle stock in Munich in 1996 included 209 vehicles. Since the delivery of Class 423 vehicles, the Class 420 trains have been delivered to other cities, sold or scrapped. For the time being, the last regular passenger service in the Munich S-Bahn network drove a train of this series, the so-called "Olympia motor coach", on 5 December 2004 on an amplifier circulation line S 8 and was since then only in the museum service at regular special trips to be found.
Due to the electrification of the A line and the resulting vehicle shortage since December 2014 again series 420 trainsets are used. These are 15 units taken over from the S-Bahn Stuttgart, but due to the lack of regular train traffic, they can not run on the main line during rush hours. They therefore take over exclusively the amplifier services on the S 2 between Dachau and Altomünster as well as amplifier rides on the west branch of the S 4 line and the S 20 line. Currently planning the S-Bahn Munich and the Bavarian railway company, 20 to 30 other units from Stuttgart to Munich to match the rising numbers of passengers. These are to be equipped with the existing units with the Linienzugbeeinflussung in order to be able to drive in the trunk tunnel.
Since the route of the line A from Dachau to Altomünster was not electrified until April 2014, DB Class 428 was primarily used. These were located in the railway depot of the Südostbayernbahn in Mühldorf am Inn. The vehicles were procured again in 1998 for the track, previously were used on the line A n-car push-pull trains with diesel locomotives. However, the entrances to the trains were not barrier-free because of steps. Following the electrification of the line, it was replaced by a branch line of S2, and Class 420s were replaced as well in June 2017.

Class 423

From the autumn of 2000, the class 420 trainsets, some of them over thirty years old, were replaced massively by new vehicles of the class 423. The new vehicle emissions were enforced line by line, as the trains could not be coupled with each other. First, the S 7 line was served by the new locomotives. By 2003, 211 locomotives were delivered. In 2004, another 23 units were procured. In 2005, four more trains were delivered, so today there are 238 traction vehicles.

Others

In 1989, the double decker trains used in the Netherlands were briefly used on the then S4 between Geltendorf and Ebersberg. Patrons were invited to fill out a questionnaire while onboard describing their experiences while boarding and riding the train. The concept was to increase passenger capacity at the same time as accommodating bicycles, prams, and wheelchairs with efficiency. The trains were pulled by a DB Class 120 locomotive at each end of the train.

Plans and further expansions

The Second S-Bahn Tunnel (Zweite Stammstrecke)

Nearly all lines use the core route through the city centre in the underground, creating a bottle-neck responsible for long and increasingly frequent delays from even the smallest disruptions. The disadvantage of current core route is the inability of trains to reroute themselves onto different tracks in an event of disruption.
After years of discussions and studies into different route propositions, a second tunnel through the city centre has been already approved with the funding of €3.85 billion and the completion date of 2028-2032. On 5 April 2017, the ground-breaking ceremony took place to commence the construction.
The second tunnel will be in length and run in parallel with the current tunnel in the south on the western portion of Hauptbahnhof and in the north on the eastern portion. It will have three underground stations and two surface stations. Marienhof, which will be built to the north of Munich Marienplatz station, will be the only all-new station on the line; other stations will be expanded to accommodate the new tunnel. With focus on express service and shorter travel time, the second tunnel will bypass six current stations between Laim and Ostbahnhof.
Most of express S-Bahn with limited stops will use the second tunnel: the proposed express S-Bahn routes are S18X, S21X, S23X, and S24X. Two of current S-Bahn routes will be transferred to the second tunnel upon the completion: S1 and S6.

Optimisation (Optimierung)

The initial design called for second S-Bahn station underneath Orleansplatz at Ostbahnhof with long pedestrian tunnels connecting to the aboveground station serving regional and long distance trains and current S-Bahn. This design received many negative criticism from the public, especially the residents in Haidhausen neighbourhood quarter. The residents have grave concern about tunnelling and earth extraction impacting their housing and disrupting their daily lives. The new EU directives call for more escape tunnels and rescue access points to be incorporated in the design. The forthcoming construction of new U9 subway station at the Hauptbahnhof requires the further tweaking of master build plans.
On 3 July 2019, Deutsche Bahn announced the new "2. Stammstrecke — Die Optimierungen". The optimisation project called for second S-Bahn station at Ostbahnhof to be moved from Orleansplatz to the southeastern side of Ostbahnhof platforms along the street, Friedenstraße. The entire second S-Bahn station will be underground and connected to the current S-Bahn platforms via staircases, escalators, and lifts. The advantages of new location are its close proxmity to the entertainment quarter in the southeast, higher capacity flow with more direct access to the aboveground platforms, better connection to Berg am Laim S-Bahn station, and platforms closer to the ground. The relocation necessitated realignment and lengthening of S-Bahn tunnels between Marienhof and Ostbahnhof.
The new EU directive requires the third tunnel for escape and rescue to be constructed between two tunnels and access points to the aboveground be added at every 600 metres. The benefit of new design allows quicker passenger evacuation from the tunnels, easier access for the rescue personnel, and simpler access for maintenance crew.
State of Bavaria and Munich city council wants the first U9 station to be built at the Hauptbahnhof at the same time as reconstruction of Hauptbahnhof main building and construction of second S-Bahn trunk line. The new changes relocate U9 platforms from the west end of regional and long distance platforms to the middle of main Hauptbahnhof building below the ground. The relocation places U9 station directly above the second trunk line station in a cross arrangement. This improves the passenger flow between two current U-Bahn lines, one current S-Bahn trunk line, and aboveground level.

S-Bahn-Nordring

An alternative route in the north has been proposed for many years. This route would use part of Münchner Nordring currently used by the freight trains and as railway bypass. The plan would call for eight new S-Bahn stations and two conjunctions to be built, totalling fourteen stations.
The advantage of using the Nordring is numerous as compared to Südring :
The discussion of S-Bahn-Nordring is ongoing with no tentative date of construction and completion as well as cost estimate.

Circular Railway (Ringbahn)

Prof. Dr. Michael Piazolo, a Bavarian state parliament representative, prepared the study for a potential Münchner Ringbahn. The proposal of building the circular railway similar to Berlin Ringbahn has recently gained more traction with city government and state parliament. The circular railway would use the Munich North Ring, the S8 line between Johanneskirchen and Ostbahnhof, the Südring between Ostbahnhof and Heimeranplatz, and a new line, to be built between Heimeranplatz and Olympiakreuz. The close proximity of Nymphenburg Palace and the west-east lines at Donnersbergerbrücke station would require the construction of tunnels between south of Heimeranplatz and Olympiakreuz.
Most of the Ringbahn would use the existing railway lines with seven S-Bahn stations currently in use. Five new surface stations and three new underground stations would have to be built.
One additional advantage of this Ringbahn concept is an airport express train service from Hauptbahnhof via Olympiakreuz, following the proposed tracking for the finally abandoned Munich Airport Transrapid. That could potentially shorten the travel time from the Hauptbahnhof on the west side, bypassing the current S2 with numerous stops along the line.

Southern Ring

The alternative to their Circular Ring, is the Südring between Ostbahnhof and Heimeranplatz, the stations do include Heimeranplatz, Poccistraße and Kolumbusplatz, which is the express variant.

Northern Tunnels along the Airport

In 2009, a Nordtunnel was proposed by Vieregg-Rössler as a further extension, which connects the main railway station with the Kunstareal. In the inner city area, the planned route is roughly equal to that of the planned U9. In addition to the S-Bahn, the route would also include regional and long-distance transport, in this way the central orientation of the Munich local transport system should be replaced by the city center. The Nordtunnel was not followed, among other things due to higher costs with at the same time lower profitability.

S-Bahn Vision 2050

On 31 March 2017, MVV announced the Vision 2050 expansion proposal. The vision for the year 2050 includes double-decked wagons, 24-hour operations, new stations, and extensions further beyond the city limit.
The possible extensions are:
Rings and Spurs :
Four-Track Expansions:
Other Projects:

Literature