A westbound (railroad direction) CSX pusher set is emerging from the north (compass direction) end of Natural Tunnel, on the NS Appalachia District. When the South Atlantic & Ohio Railroad elected to use Natural Tunnel as a passage through Purchase Ridge, it was obliged to blast out this short man-made bore through a thick rib of rock inside. Stock Creek (to the right) passes through a lower and smaller opening to get to the other side. The roof of the tunnel is a riot of color from 125 years of locomotive exhaust, various colors of rock strata, and all kinds of algae growth. CSX has used this route between Big Stone Gap, VA and Frisco, TN since 1985.