Quoted By:
I have to say Norrköping, Sweden.
A small 1st generation system in a town of 80k people, quitly stayed open with rolling stock bought second hand from Germany when most other closed. It even survided "dagen H", when Sweden turned to right hand traffic, which effectively killed Malmö's, Helsingborg's and Tockholms trams (even if one line in Malmö stayed open till 73).
Instead it was expanded cautiously with mostly dedicated lanes, of course. Today it forms the back bone of Norrköping's small transportation system.
