My guess is that the picture was taken in the throat of the previous C&NW downtown station, just north of the trainsheds and passenger platforms. It was torn down in the 1980s to make room for the current Ogilvie Station.
You can see a photo of the front of the station at:
http://www.dhke.com/CRJ/station.htmlThe building with the two antennae is Sears (now Willis) Tower, not the Hancock Building, so this view looks southeast. Behind the grey buildings would be Canal Street.
The C&NW (and now Metra) stored locomotives on these tracks during off-peak hours between rush hours. In more recent years a GP-9 was also kept on these tracks.
The Beaux Arts architecture of the buildings in the background is the same as what is left of the old terminal which you can see along Clinton Avenue just south of Lake Street. The old powerhouse which is being converted into condos has the same architecture.