I think that a study was done about a year or two ago that most of these no longer work. There seem to only be a handful of these around the city. I remember seeing a lot more when I was a kid.
This one actually looks like it might still work. I see so many with the cords ripped out that even if the base was functional no one could place a call. Why someone decided to discard a shoe on top is beyond me, but hey, I thought it was a great photo op.