Source: Chicago Transit Authority
Below is the description from Flickr:
Postcards were issued in the 1940s to promote the new subways being opened under State and Dearborn Streets. This 1941 sketch was one of the images published and is an artist’s rendering of what the State Street Subway, still under construction, might look like once opened. The view depicts a cross-section of the street, mezzanine and subway platforms and tubes with crowds of people filling sidewalks on State Street above as well as taking advantage of direct retail connections from the station complex.
The specific location depicted here (one can deduce the location easily, with the flagship The Fair store on the left and The Palmer House on the right) is a view looking north on State from Adams. The subway mezzanine in view is the Monroe-Adams mezzanine (still today an entrance to the Monroe station on the Red Line) and the train in the tunnel is drawn as a Shoppers’ Special–the name for certain express services run from several ‘L’ branches to the Loop, catering to mid-day shopping trips to downtown during that era.
Certain details of the finished design would change for various reasons various reasons, including materials issues related to World War II, but the detailed image is remarkably close to what the finished stations would look like. Interestingly, the subway cars the artist drew are basically of then-new, experimental “Bluebird” cars which had recently been put into service onto the BMT lines of the New York City Subway. The Bluebird model cars (or similar) were under consideration for purchase here in Chicago, at the time.