The CTC panel in Smithboro Tower controlled the majority of the Penn Central (ex-PRR) line across southern Illinois from Terre Haute to East St. Louis. At Smithboro, the PC line was crossed by the Burlington Northern (ex-CB&Q) line from Galesburg to Paducah.
Oh the stories these special buildings could tell. Originally the brains of the rails they monitored, working to insure effecient rail service for our nation! A tribute!