In 1970 AGS reported 3854 million net ton-miles (5627 million net tonne-kilometers) of revenue freight and 105 million passenger miles (169 million passenger kilometers); at the end of that year it operated 528 miles (850 km) of road and 1,084 miles (1,745 km) of track. (Those totals do not include Class II subsidiary Louisiana Southern.)
The two companies began construction from their termini outside Alabama. The Wills Valley opened the line from the Nashville and Chattanooga at Wauhatchie, Tennessee to Trenton, Georgia by December 1860, operating to Chattanooga via trackage rights over the Nashville and Chattanooga.[12] The North East and South West began its line at Meridian, reaching a connection with the Alabama and Mississippi Rivers Railroad (later the Selma and Meridian Railroad) at York, Alabama by 1860, and was leased to the latter company.[13] A group of Boston capitalists headed by John C. Stanton gained control of the companies after the Civil War, and the legislature passed a law in November 1868 to merge the two as the Alabama and Chattanooga Railroad. (Georgia, Tennessee, and Mississippi renamed their portions in March 1869, February 1870, and May 1871, respectively.) The entire line was completed in May 1871, creating a diagonal link across Alabama.[14] However, due to nonpayment of interest on state bonds, the state of Alabama seized the property in mid-1871, and it was operated by other parties (including the president of the connecting New Orleans and Northeastern Railroad) until November 1877, when it was reorganized as the Alabama Great Southern Railroad by Emile Erlanger and Company.[8][9]
The AGS incorporated the Wauhatchie Extension Railway in April 1914 to continue the line from Wauhatchie to a junction with the Southern subsidiary Memphis-Chattanooga Railway west of Lookout Mountain. The property became part of the AGS in February 1917 and was completed later that year, giving the AGS a new route into Chattanooga, via the extension, trackage rights over the Memphis-Chattanooga, and a lease of the Belt Railway of Chattanooga.[8]
Southern Railway trains ran over the territory of the AGS. The Queen and Crescent ran on its territory until its termination in 1949.[21] The Birmingham Special ran on the AGS' Chattanooga to Birmingham segment until its discontinuance in 1970. The Pelican also ran on its entire length, lasting to 1970. The Southerner ran on its territory southwest of Birmingham until its termination in 1970.[22] Today, Amtrak's Crescent operates on its territory southwest of Birmingham.
^Moody's Transportation Manual, 1984, p. 96: "1969-70 Corporate Simplification: In 1969, Company continued its program of simplifying the corporate structure of the Southern Railway System. First, in January, Company acquired the minority interest in Alabama Great Southern Railroad Co. (AGS) [...] Concurrently, the New Orleans & Northeastern Railroad Co. was merged into the AGS."
^Association of American Railroads, Yearbook of Railroad Facts, 1970, p. 5: "On January 3, 1969, the New Orleans & Northeastern was merged into the Alabama Great Southern."
^Association of American Railroads, Yearbook of Railroad Facts, 1971, p. 5: "Three railroad unifications were consummated in 1969. [...] the New Orleans and Northeastern became part of the Alabama Great Southern on January 31."
Railroads in italics meet the revenue specifications for Class I status, but are not technically Class I railroads due to being passenger-only railroads with no freight component.