The situation today
The Munich metropolitan region is one of Germany's growth centres. The region owes its dynamism in part to the direct rail links connecting surrounding towns and communities with Munich city centre.
The Munich S-Bahn already transports around 840,000 passengers a day and its trains travel over 20 million km a year. This makes it one of the largest S-Bahn systems in Germany. However, 40 years on, the system is reaching the limits of its capacity, even as the population continues to grow. The time has come to lend Munich's S-Bahn system a helping hand.
Rising transport demand continues unabated
When the Munich S-Bahn began operations in 1972, it was designed to carry 250,000 passengers each weekday. Today, almost 6 million people live in the Munich metropolitan region, and the S-Bahn transports around 840,000 passengers every weekday. The population of Munich and its metropolitan region is forecast to continue rising rapidly between now and 2030.
As the population continues to grow, the number of passengers using regional and local public transport will also increase– and that's a good thing. After all, from the standpoint of climate protection and sustainability alone, everyone should be encouraging more people to use public transport.
However, there's a catch: all of the city's S-Bahn lines currently take the same core route through its city centre. This route has become a bottleneck in Munich's regional and local transport system. On its own, the existing core route cannot cope with the rising tide of commuters and the resulting growth in passenger numbers.
S-Bahn network reaching its limits
When it opened for service in May 1972, the S-Bahn was designed to carry approximately 250,000 passengers a day during the working week. Now, however, the system's daily passenger volumes have reached 840,000 from Monday to Friday. In order to meet the increased demand, multiple investments have been made in the existing core route in recent decades. Additional dedicated S-Bahn tracks have been built, routes have been added (especially connections to the airport) and new stations opened. In addition, service frequency has been increased to every 20 minutes, and on some S-Bahn lines, trains even run every ten minutes during rush hour.
Adding trains not an option
All eight S-Bahn lines run along the existing core route between Donnersbergerbrücke and Munich East stations. To improve performance, a modern train protection system known as continuous automatic train-running control was installed between 2003 and 2004. This has enabled a throughput of 30 trains per hour in each direction, compared with 24 previously.
During rush hour, an S-Bahn train now runs through the tunnel every two minutes. This high frequency is only possible because at the busiest stations – Munich Main Station, Karlsplatz (Stachus) and Marienplatz – platforms are available on both sides of the train to allow simultaneous boarding and alighting, a configuration known as the Spanish solution.
With a two-minute headway between trains, however, the capacity of the existing core route is now exhausted; the S-Bahn trains cannot run any closer together than they do already. A train requires a specific amount of time to enter and stop at each station, to allow passengers to board and alight and to depart again. A certain distance has to be maintained between trains for safety reasons as well.
Impact of S-Bahn network disruptions
Many different things can disrupt S-Bahn services. They include storms, medical emergencies and police operations (for example in the case of unattended luggage or persons on the track) in addition to problems with signal boxes, overhead lines and points, not to mention faults with rail vehicles themselves.
The problem is all too easy to imagine. With a train interval of only two minutes and all eight S-Bahn lines using the same track throughout the city centre area, disruption on one line inevitably affects all the other lines as well. A domino effect is created: if one S-Bahn train is significantly delayed, other S-Bahn services also run late as a result. And punctuality in particular is crucial in making local public transport an attractive option for passengers.
Passengers experience particularly extensive disruptions when incidents occur directly on the core route. All S-Bahn lines use this route, so when it is blocked, passengers are often unable to reach the city centre by S-Bahn at all, given the lack of options for detours. Depending where the disruption occurs, S-Bahn trains are forced to terminate early in Pasing, at Munich Main Station, Munich East, Giesing or Heimeranplatz. Passengers then have to change to another means of transport, all of which also have limited capacity. A second core route will ensure passengers can still reach the city centre even when there is major disruption.
Solution to address the current situation
In the past, various solutions have been studied and discussed in depth.
The verdict: building the second-core-route tunnel is the best way to eliminate the bottleneck in the Munich S-Bahn system. This will enable local public transport to keep pace the metropolitan region as it grows. The project is also essential for creating better links between the overall metropolitan region and Munich city centre and for providing a fast and attractive connection to Munich Airport.