Wow good catch Johnny, that's one railroad I never knew existed, it's hard to tell if it connected to the Dunning tracks. If you look where it comes off the C.M. & ST. P. near Milwaukee you can see the "Y". There is no "Y" at the Dunning track. But that may be just how it was drawn on this map, very cool.
I also see the street I grew up on, Richmond St was originally Hum
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Forgotten Chicago Sightings