Well, the route began as the Western North Carolina railroad at Salisbury in the 1850's and reached as far as Old Fort at the edge of the most rugged part of the Blue Ridge mountains, which contains Mt. Mitchell, the highest peak in eastern north america. The Southern Railroad took over the line and built west through Ridgecrest toward Ashville. It is now part of NS's Piedmont Division. This section of the line rises 1000 feet in about 13 miles, with 2.7 percent grades at times, culminating in the 1,800 foot Swannoa tunnel at elevation 2535 feet into Ridgecrest. The route has enough degrees of curvature to equal 8 complete circles. EMD has used this section of track as a test track to test wheel slip control systems.
The line was completed between 1875 and 1892 and at one time one-half of North Carolina's convict population worked on the line. 461 of them died in the attempt, mostly from blasting accidents.
This all comes from the September 2006 issue of Trains, which was my inspiration to model the line.