In Melbourne we loved our Tram Trams that run down the middle of the street and hold up the traffic. The W class trams were all fazed out and replaced with "light rail". Bigger Faster Better. Not. Melbourne has a good mix of tram and train - yes you take athe train to the city (a through route via the underground loop) and get on a tram for the last km. Small frequent trams are better for this and require lighter track. I think there was a recent HN article to this effect.
Trams holding up traffic? Yes, the injustice of trams that can carry 100 to over 200 people (depending on class), delaying a handful of cars carrying (on average at peak times) 1.15 people each from getting through each intersection...
