The railroad below has a long and tangled history dating back to wagon road surveys as early as 1831. A north-south route across the Appalachian Mountains for commerce and travel was long sought, but location here was always negated by rugged topography. By the 1880s, recognition of the region's abundant coal resources convinced railroad and coal barons that a line was feasible, if not necessary, to develop those deposits. Many railroad companies showed interest in The Breaks, but General John T. Wilder of the Charleston, Cincinnati & Chicago Railroad was first to lay title to property in this area. That company collapsed in 1890, and those rights eventually passed to the South & Western Railway, headed by George Lafayette Carter, and finally to the Carolina, Clinchfield & Ohio Railroad, the Clinchfield Line. The route through The Breaks was completed in 1915, but only after litigation with the Chesapeake & Ohio Railroad, which claimed prior rights through the gorge in 1902. The two lines connected at Elkhorn City, Kentucky. After many mergers and buyouts, the inheritor of the Chesapeake & Ohio acquired use of the line, CSX Transportation, whose coal trains still traverse the gorge. At the time of completion, the Clinchfield was the costliest American line per foot yet built, in no small part because of construction obstacles in The Breaks. Upstream, the 921-foot Towers Tunnel passes under the saddle between the Towers and the Chimney, avoiding the great entrenched meander bend of Russell Fork. Downstream, the 1,523-foot Stateline Tunnel parallels Russell Fork, and the gorge wall of the tunnel is only a few feet thick. Further downstream, the track sweeps around Potter Flats and then crosses the river over Pool Point Bridge, which was the longest steel-span bridge in the world for a short time after construction.