The Pigeon Mountain Tunnel. March 17, 1888 the construction of this 92 mile stretch of the Chattanooga Southern Railway began. The line would run from Chattanooga to Gadsden serving the transportation needs of agricultural cotton and iron ore. It was proposed to extend the lines to Columbus, GA to connect with independent lines giving a route to Florida and coast points. It became apparent that there was not enough freight via passengers or cotton, and the iron ore could not be economically mine