On 31 May 1992, S1 trains were extended to Hohen Neuendorf, and to Oranienburg after the fall of Berlin Wall.

After the opening, three pairs of trains ran between Berlin and Oranienburg every day, two of them on to Neubrandenburg.

That year, the number of daily suburban train pairs on this section increased from 8 to 13.

Work on the four-track expansion between Frohnau and Birkenwerder with separate systems for long-distance and suburban traffic began as early as the end of 1918, initially as an emergency measure.

Electric train operations from Berlin via Hohen Neuendorf began on 5 June, initially to Birkenwerder, and the section to Oranienburg station followed at the beginning of October.

Due to the infrastructure being destroyed or dismantled as a reparation payment to the Soviet Union, improvisation had to be carried out for several years.