This abandoned railway was originally built by the Georgia Midland and Gulf Railroad, chartered in 1886 to build a 99-mile line south from McDonough through Griffin, Williamson and Woodbury to Columbus. The line ran parallel to the Central of Georgia through Experiment and Griffin and crossed the CofG at the "Southern Diamond" in downtown Griffin. The line was completed on December 1, 1887, but from the start was barely able to generate enough revenue to pay its construction debts. In 1890, the GM&G leased the Columbus and Southern Railway, which operated an 88-mile line from Columbus to Albany, in hopes to improve the financial condition of the GM&G. The lease did little to help the GM&G and within a year it gave up the lease. For most of its existence, the GM&G struggled to stay out of receivership and in 1896 succumbed to J.P. Morgan and the Southern Railway. In 1896, Morgan purchased the GM&G to benefit the Southern, reorganized and renamed it as the Georgia Midland Railway. A long term lease of the entire line was given to the Southern and within a few years was absorbed into its system.
For many years this route made up Southern's access line to Columbus from Atlanta, and it was known as the "M" Line. This is the rail line that President Franklin D. Roosevelt used to reach his "Little White House" in Warm Springs, GA. Southern Railway abandoned the section from Rover, just northeast of Williamson, to Columbus in the early 1980s before the name change to Norfolk Southern. The right-of-way from Rover to Columbus is actually railbanked by the State of Georgia. Norfolk Southern sold the section from Experiment to Towalaga in 1991 to Roosevelt Railroad Museum, Inc. The section from Grove (south of McDonough) to Greenwood to GA Route 155 in Luella is still operated by NS. The NS Training Center is near Greenwood. NS also operates a portion of the line from Griffin to Westbrook to Rover.
Towns along the line, from Rover to the southwest were Williamson, Jolly, Concord, Neal, Molena, Woodbury, Raleigh, Warm Springs, Nebula, Shiloh, Oak Mountain, Waverly Hall, Ellerslie, Midland, Flat Rock and into Columbus.