>>1305083>>1305083Line 31 in Zurich actually replaced tram nr 1 in the 50s or 60s, that's why there's no tram nr 1. This didn't work out too well so no further lines were converted, but new trolleybus lines were built elsewhere, and tram line 1 was never rebuilt. But line 31 is definitely the most heavily used trolleybus line, so it got biarticulated units some time ago. The outermost portion of line 31 replaced a stretch of tram nr 2 as well, but now that the new interurban tram ("Limmattalbahn") is being built line 31 has been cut back, and tram line 2 is being extended to more or less its former terminus.
Pic related shows buses, trolleys and trams in Zurich. Colored lines up to nr 15 are trams, the other colored lines are trolleybuses, the blue lines are buses.