It's just because the public transport of Zurich is very proud about it's very frequent schedule. There was a funny commercial thematizing this, showing the troubles of photographing in Zurich. Watch it: [link]
Translation of the phrases in the spot -Tagashi Akai from Japan shows his holiday slides from Zurich. -We have the densest timetable in Europe. -Sorry dear tourists!
Translation of the phrases in the spot
-Tagashi Akai from Japan shows his holiday slides from Zurich.
-We have the densest timetable in Europe.
-Sorry dear tourists!
Nice picture by the way