It was obviously on Auckland-Wellington-Auckland, and Pacific Blue do turn planes around rather quickly.
I only took 110 photos.
If required to turn around very quickly, a tram's turn-around capability is limited solely by how long it takes the driver to walk from the cab at one end to the cab at the other, and for all the passengers to disembark/board. In peak hour, that's basically what they do. Offpeak, I think they're given about six minutes at the terminus on my route. I've gone on photo treks alongside the line in Royal Park, which is about 15-20 minutes from the terminus, so if I hang around for an hour, I'm guaranteed to get the same trams I saw at the start coming back at the end. Don't think I've ever stayed long enough to get the same tram a third time, though.
The LaTrobe Street bridge is a bit of an extreme case for me, since almost every suburban line in the city, plus every single regional passenger train in the state passes under it, it has three frequent tram routes on it, one freight service also passes under it, and even if absolutely none of them are running, the bridge also cuts straight across the middle of stabling yards so I can photograph stuff parked there while I wait.
I don't do nearly as many photos in other locations. Yesterday, I photographed two trains on the Albion-Jacana line, for a result of about 15 photos.