The mountains of northwest Georgia were the biggest obsticle to connect a train line from Chattanooga to Atlanta in the earliest days of the railroad. The most formidable challenge was the Chetoogetta Mountain in Whitfield County.
The first tunnel at this location was completed in 1850 with a tunnel of 1477 feet. Eventually, it became insufficient and a second tunnel was built in 1928. That second tunnel is the one that lines up in this image with a length of 1527 feet. The second tunnel parallels the original tunnel which is to the right and you can walk through today.
roadsidegeorgia.com/city/tunnelhill.html
