The commuter station at 75th Street was called Windsor Park because when the Illinois Central commuter system was built that was the name of part of what is today Rainbow Beach. The beach originally had several sections with different names, including Windsor to the north of 75th Street and Manhattan to the south.
These were all consolidated under the name Rainbow Beach after WWI, in honor of the Rainbow Division.
The parks and beaches in those early days of the 20th century were an important local amenity and a draw for tourists, drawing crowds as perhaps never since. That is a major reason there were so many grand hotels built along the shore on both the south and north side. Florida was still a swamp when the Burnham Plan created Chicago’s magnificent recreational shoreline, and people came in great numbers to use it.
Check below for images of vintage postcards over the years featuring the various names and crowded scenes.