No, no one told me what it is; I just know these things. In the previous 1906 photograph, you can clearly see the man using it. The same man, with a newspaper in his coat pocket is still standing in the same spot in today's photograph; but he's not leaning on it and a pedestrian is blocking the view of him holding it. Another pedestrian, apparently, cannot wait for the next streetcar.

I hadn't thought about it but I realize, looking at this photo, that the notion of a "crosswalk" really is a modern invention; there was no particular reason for such a thing before the streets became clogged with cars.