Because the ITR had some valuable trackage and lineside freight customers, it was acquired in June 1956 by nine Class I railroads. These collectively continued to operate ITR as a diesel-powered short line to carry freight to the acquiring railroads. The co-owned reorganized Illinois Terminal Railroad took down its trolley wire and abandoned much of its trackage, particularly the interurban street running in towns and villages. At various points ITC track was connected to trackage of adjacent lines and was available for optional routing. For the following 25 years (1956-1981) the ITC continued to operate diesel-powered trackage north and east of St. Louis, providing freight business for the railroads that owned it. The Norfolk and Western Railway purchased its partners' interests in the Illinois Terminal Railroad on September 1, 1981, and ITC officially merged into the N&W on May 8, 1982.