In December 1888, the SA&M was organized as the successor to the Americus, Preston & Lumpkin Railroad, a narrow-gauge line running from Louvale, near the Georgia-Alabama state line, to Abbeville, on the Ocmulgee River. The change was made by a group headed by Americus banker and lawyer Samuel H. Hawkins, who saw greater potential in the line than had been realized up until then.
An extension from Abbeville to Lyons opened in June 1890, and an extension from Louvale to the Chattahoochee River was completed a few months later. At Lyons the SA&M connected with a new line to Savannah opened in May 1890 by the Savannah & Western Railroad, a subsidiary of the Central of Georgia.
The new Abbeville-Lyons and Louvale-Chattahoochee River tracks were constructed at standard gauge. Meanwhile the 106-mile Louvale-Americus-Abbeville trackage, which was all narrow gauge, was rebuilt to standard gauge in 1889-90.
At Abbeville, the SA&M connected with its fleet of riverboats operating on the Ocmulgee and Altamaha rivers to Darien, Brunswick, and Savannah. The railroad owned five such boats in 1891. These were apparently sold not long after the rail connection to Savannah was completed