[someMidTowner]

^At first I just assumed it was rails for the window cleaning unit, on closer inspection, it now appears to have banked turns.....Rooftop Velodrome Deathmatch anyone?

 

[junctionist]

It is indeed a running track. It was progressive urban planning policy in the 1970s to encourage creative uses of rooftops. First Canadian Place also has a running track.

 

[waterloowarrior]

Check out the Streets in the sky clip from this video http://www.bbc.co.uk/news/world-20578262