The now-abandoned rail line from Chattanooga to Gadsden was constructed in 1890-91 as the Chattanooga Southern Railway. Built to haul coal, iron, and timber, it entered receivership after just a few years of operation and was reorganized in 1896 as the Chattanooga Southern Railroad.
In 1911 it was reorganized again, this time as the Tennessee, Alabama, and Georgia Railroad. Another receivership in 1922 resulted in the line becoming the Tennessee, Alabama, and Georgia Railway.
It was also known by the nickname TAG Route.
In 1917 the TAG had 6 locomotives, 6 passenger cars, 6 box cars, 15 flat cars, 45 coal cars, 1 stock car, 2 cabooses, and 9 service cars.
A substantial part of the railroad's early freight business came from iron ore mining on the west side of Pigeon Mountain. The Estelle mines there were the main source of ore for the Chattanooga Iron & Coal Corporation's furnace at Chattanooga.
The TAG had a branch line from Menlo to Coe; it was abandoned in 1920. (The branch left the main line at Coe Junction, about 2.5 miles south of Menlo.)
Southern Railway purchased the line in 1971.
The middle portion of the line was abandoned in the early 1980s. The northern section of the line, from Chattanooga to Hedges, was operated for a time by the Chattooga and Chickamauga Railway, but it has been inactive since 2009.