The three miles of track from Melrose, NC [at the base] to Saluda [at the crest] is the steepest mainline grade on any Class 1 railroad in the United States. The average grade is 4.7% and there is a stretch that measures 5.1%. In railroading a 2.5% grade is considered steep.

Here SD60, 6556, dynamic brakes whining to keep the train in check, creeps along the shallowest part of the grade at Sand Cut.