The Rockdale, Sandow, and Southern Railroad Company was chartered on June 13, 1923, to acquire and rehabilitate an industrial railroad constructed by the Federal Fuel Company in 1919. The six-mile line extended from Marjorie on the International-Great Northern to the Federal lignite mine near Millerton, the first surface lignite mine in Texas. However, the equipment employed by Federal Fuel to strip the overburden and lignite failed to work as expected, and the company entered into voluntary bankruptcy in late 1920. The Standard Coal Company, a new organization, took over the property the following year and in 1922 conveyed the mine to a subsidiary of the McAlester Fuel Company. In order to promote lignite, McAlester renamed the mine site Sandow, after Florenz Ziegfeld's strongman. The railroad had a capital of $10,000 and a business office in Sandow. The members of the first board of directors were E. A. Camp, John M. Reed, L. W. Sledge, John T. Hale, and E. M. Camp, all of Milam County; and V. C. Robbins and A. P. Rudowsky of Pittsburg County, Oklahoma. The RS&S, also a subsidiary of McAlester Fuel, began operation on February 4, 1924. Virtually all of its traffic originated at the mine, and the fortunes of the railroad depended on the demand for lignite. In 1926 the Rockdale, Sandow, and Southern Railroad reported passenger earnings of three dollars and freight earnings of $63,000 and owned four locomotives and three cars. By the late 1940s, however, petroleum and natural gas had captured most of the markets supplied by McAlester, and the last major customer, the University of Texas, converted to natural gas on October 1, 1950. The last car of lignite was loaded by the mine on October 18, 1950.
A new era for the RS&S began in July 1951 when the Aluminum Company of America announced plans to build a smelting plant near the mine. As a part of the project, Alcoa received authority from the Interstate Commerce Commission to acquire control of the RS&S, which was now authorized to operate in interstate commerce. Previously, the RS&S handled intrastate traffic only. The railroad was upgraded, and about three miles of track was moved in order to serve the new Alcoa plant better. Construction of the Rockdale Works began in the fall of 1951, and the first carload of aluminum was shipped in November 1952. Although it is independently operated, the RS&S has become an integral part of Alcoa's Texas operations. Unit trains carry material between the Alcoa facility at Point Comfort and the Rockdale Works on the tracks of the RS&S, the Union Pacific, and the Point Comfort and Northern, another Alcoa-controlled railroad. The RS&S carried passengers until about 1950, although passenger traffic was light. A Pierce Arrow, modified to run on rails, provided passenger accommodations in later years. This allowed the RS&S to retire its combination baggage and coach car, which was sold to Twentieth Century Fox in 1945. The car has subsequently appeared in numerous movies and television programs. The bell from steam locomotive number 3 has served since 1954 as a Victory Bell for the winner of the annual football game between the Rockdale Tigers and the Cameron Yeomen. In 1990 the railroad had revenue of less than $5 million and hauled metallic ores, metal products, and petroleum products. In 1990 the company owned three locomotives and leased 159 freight cars.