Aproaching Düsseldorf-Flingern on a southbound S68-trip. This line has a generally weird mode of operation, being oneway only between Düsseldorf and Wuppertal-Vohwinkel whilst the vehicles travel both ways. This happens with six roundtrips in the morning rush hour from Vohwinkel to Düsselorf HBF and 5 roundtrips in the afternoon from Düsseldorf to Vohwinkel. It seems like there are 5 trips in the morning and 4 in the afternoon in the vice versa direction done without passengers... and those are the ones I'm after, as they end up to be with good sunlight. One 420 seems to spend it's night at Wuppertal, probably parked up at Oberbarmen station.