hour to 24 trains. Since then, the interrupted amplifier lines of the S2 are tied through, in Munich, however, could increase the power to 30 trains per hour. An equal capacity increase in Frankfurt, however, would have required the installation of line influence on the line and in the vehicles and was omitted for reasons of cost. The City Tunnel Offenbach is long and has three underground stations, which are served by the lines S1, S2, S8 and S9. Opening: 1995 There is a long tunnel at the airport, which passes under several highways and buildings and has a three-track subterranean regional train station below the airport terminal. Until the opening of the airport's long-distance railway station in 1999 also held intercity trains. Since November 2016, a long relocation of the Stadium - Airport Regional Station section is under construction to create a new Gateway Gardens Station under the development area of the former US military settlement until December 2019. The tunnel is broken up and newly built. In Mainz, the S8 runs in the direction of Wiesbaden through the two old, successive railway tunnels between Mainz Roman Theater and Mainz Main Station, in the opposite direction it travels the continuous "New Mainz Tunnel". The (single-track) station Schwalbach (Limes), which is served by the S3 line, lies underground underneath the market square of the Limes town. The tunnel, which was built together with a parallel road tunnel, is about as long as the station itself. Immediately north of the station Eppstein in the Taunus (line S2) is built in 1877, long Eppsteiner tunnel, for 2010, a new replacement tunnel was built because of otherwise problematic renovation work. The future Plans for the system include a line to Hanau via Maintal, largely running north of the river Main. This would extend the S7 from Riedstadt-Goddelau, that currently terminates in the main hall of the Hauptbahnhof, with a service to and from Fechenheim (replacing the station at Mainkur) four times an hour of which half would extend to and from Hanau. The S6 to Friedberg will get its own track to be independent of long-distance and regional traffic on the Main-Weser-Bahn. In the 1980s and 1990s, it was planned to expand the double track to a third track. Later, the plan was changed to build the S6 for their entire run until Friedberg own two tracks for a scheduled operation independent of