On a hot, muggy August day, Southern Pacific SD45R 7406 brings an intermodal train into Tucumcari, New Mexico. Tucumcari used to be the interchange between the SP and the Rock Island. When the RI finally ceased operations on March 31, 1980, and on June 10th of that year, the Interstate Commerce Commission yesterday approved the sale of the Rock Island Railroad's 965-mile Tucumcari Line, running between Tucumcari, NM, and Saint Louis via Kansas City , to the Southern Pacific for $57 million. Five months earlier, this train would have been on the Rock Island, but on this August 23, 1987, afternoon, the SP was on home rails, often called the “Cotton Rock” following the acquisition, since much of this line was owned by SP subsidiary Cotton Belt.