There was in the distant past three routes with Chicago to St. Louis passenger service. The CM&O, the ICRR, and the C&EI. Since the C&EI was slightly longer than the other two and did not have much in the way of significantly sized intermediate points, it dropped out early, I think in the early 1950's. The GM&O was always the fastest and carried the most people, but the ICRR was in the game until at least the mid 1960's, although with only a single train from somewhere around 1960 on.
Also the Wabash; but I don't know the route or if it's still around.
I believe the Wabash route, the route of the old
Bluebird is still around. I can't say for 100% certain the track on its entire Chicago-St. Louis run is still around, but I believe that to be the case. It ran on today's Norfolk and Western route, and from its origins in Chicago, ran through Forrest downstate to Decatur and then through Taylorville, Litchfield, and Granite City to St. Louis. Again, so far as I know, the track is still there. I know it is north of Decatur; my aunt and uncle live a couple miles from this line and when I visit there the sound of the train's horn wakes me up daily around 6:30 AM when a freight passes through. Better than any alarm clock!!