Finance for the project was agreed on 4 December 1986, and planning approval was achieved at the end of 1990, allowing construction to begin.

Line S2—which had previously terminated at Muhlberg—was diverted to Frankfurt South station.

Following the completion of the upgrading of the Rodgau Railway as well as the route to Dietzenbach on 23 March 2001 lines S1, S2, S8 and S9 now run through the Offenbach City Tunnel.

Limited capacity in the Frankfurt City Tunnel until 13 June 2010, meant that line S2—in contrast to the other lines—could only run every half-hour, while additional peak hour S2 trains could only operate between Dietzenbach and Offenbach Hauptbahnhof and between Frankfurt Hauptbahnhof and Niedernhausen rather than use the tunnel.

In the course of the Offenbach City Tunnel, S-Bahn trains stop at three stations: Kaiserlei, Ledermuseum (Leather Museum) and Marktplatz.