>>1281738Some of the stuff on San Francisco's F line is even older. They've got a really interesting thing going there, a whole major tram line through a modern city that runs a crazy fleet of historic trams from all over the world, including, interestingly enough, a whole bunch of ex-Milan Peter Witts. I think this is the oldest thing in regular service on the line, built in 1912 for the city of SF and still in normal timetable service today.
That said it's a bit of a mixed up situation, it's not that clear HOW frequently certain cars operate, and a lot of their fleet haven't been in continuous service since built but were instead pulled out of museums or scrapyards decades after their original retirements and were restored back to operational condition.