This article has multiple db bahn map pdf. Unsourced material may be challenged and removed. Statements consisting only of original research should be removed. Note the dual role of S-Trains with many branches from the suburbs combining to service a busy rapid transit like corridor in the city.
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 with S-trains stopping at all stations, while other mainline trains only calling at major stations. They are slower than mainline railways but usually serve as fast crosstown services within the city. S-trains are 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.
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. 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 high frequency corridors. In many cases, the central corridor is an dedicated underground line in the city center with close stop spacing and a high combined frequency similar to metro systems. Berlin’s S-Bahn, which is regarded as a tourist attraction. However, in more lightly used sections outside the city center, 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 transportation purpose: local transport within a city center and suburban transport between central boroughs of larger cities, and to suburbs. 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.