Offenbach Ost station is the second most important station after Offenbach Hauptbahnhof of Offenbach am Main in the German state of Hesse. Today it is served exclusively by the Rhine-Main S-Bahn. Although Offenbach Hauptbahnhof is served by some Regional-Express services and a few intercity services each day it is rated as a category 4 station, while Offenbach Ost station is now rated as a category 3 station.HistoryOffenbach Ost station was opened on 15 November 1873 on the Frankfurt-Hanau line. On 30 October 1896 the Rodgau Railway (Offenbach–Reinheim line) was opened.Line S1 of the Rhine-Main S-Bahn has been operating on the Rodgau railway since 2003, not to Reinheim, but only as far as Rödermark-Ober-Roden station. Between Dieburg and Reinheim the line has been dismantled. On 23 May 1995, the Offenbach City Tunnel was opened. S-Bahn lines S1, line S2, line S8 and line S9 run through the tunnel to Wiesbaden Hauptbahnhof or Niedernhausen via Frankfurt (Main) Hauptbahnhof underground.