An Illinois dispute over a $21.4 million railroad injury award is now percolating at the nation’s highest court.Lawyers for Norfolk Southern Railway Co., which was forced to pay the record-breaking award to a conductor whose foot was smashed between two cars at a Chicago rail yard in 2011, have asked the U.S. Supreme Court to step in and rule a jury instruction in the case unfairly swayed the outcome.Lawyers for the conductor, Michael Parsons, argue that even if the trial judge in the case shouldn’t have given …