Although Norfolk Southern Corp. has made material progress in its cost cutting initiatives in 2016, RBC Capital’s Walter Spracklin believes further efficiency gains would be much more difficult to achieve going forward.The analyst downgraded the rating on the company from Sector Perform to Underperform, with a price target of $113.Unappealing Risk/Reward“With NSC valuations now hitting peak levels, we believe the risks to achieving those targets do not match the upside return,” Spracklin mentioned.Norfolk Southern shares have appreciated 22 percent since November 2016, outpacing peers. However, with the 2018 earnings multiple having risen to the highest level among the majors, the analyst believes that it would be difficult for the company to achieve efficiency targets.This would result in an unappealing risk/reward, Spracklin explained.Source