Saluda Grade is the steepest standard-gauge mainline railway grade in the United States. Owned by the Norfolk Southern Railway as part of its W Line, Saluda Grade in Polk County, North Carolina gains 606 feet (185 m) in elevation in less than three miles between Melrose and Saluda. Average grade is 4.24 percent for 2.6 miles (4.2 km) and maximum is 4.9% for about 300 feet (91 m).