I finally completed all of the S-Bahn routes during Stage 53 of the Grand Tour de Öffentliche Verkehrsmittel. This was the S3 running from West to East and I took in some brutalist architecture and cycled through the long stretches of forest. There was also a refreshing summer rainfall too on the way back to central Berlin.
A tour of the forests and waterways in the East of Berlin plus forays into Brandenburg made up most of Stage 23 of the Grand Tour de Öffentliche Verkehrsmittel. Plus a reminder to check ferry timetables in the future!