Union Avenue Tower was the west corner of the wye south of Union Station. It had a pistol grip machine. The top center (north) of the track diagram are the connections to the CNW and St. Charles Air Line. At the close end (east) of the diagram are the north and south legs of the wye. The north leg (turning up) goes to Union Station. The south leg was used mainly by intracity freight transfers to and from the Q's Clyde Yard in Cicero. The full wye was used to turn the Q's intercity trains. At the time of the picture there were no trains in the plant (no lights on the diagram).