A big old abandonned brick building on the east side of Halsted north of 103rd is called The City Of Chicago SW Substation, can't see in the windows...is this a relic of the street car era? Insull? Tesla? (just kidding) has to be after 1890, the Calumet St Railway started in 1892 but was east of here.

I found a reference to the building in a 1919 City Comptrollers report under the category "Municipal Street Lighting System Bond Fund". Not street car, ComEd, or railroad related, only local power distribution for street lights.

http://books.google.com/books?id=zmEVAAAAYAAJ&pg=PA140&lpg=PA140&dq=city+of+chicago+southwest+substation&source=bl&ots=-yieLTWYgl&sig=Rh-UMZVtrOTVVdU-lwlBBu_nI4Y&hl=en&sa=X&ei=udmDUfjSFMqwygGY3oEo&sqi=2&ved=0CDsQ6AEwAg#v=onepage&q=city%20of%20chicago%20southwest%20substation&f=false

It was designed by City Architect Charles W. Kallal. More info on him and his buildings here (but not much info about the building itself):
[url=http://chicagosteppes.mrdankelly.com/?p=64]Charles W Kallal[/url]

The City maintained some of it's own electrical system in the early days of electric street lighting. There are still a number of them around on the South Side.