The Atlantic Coast Line Railroad's Florence—Robbins Line (K Line) was one of the company's secondary main lines that ran from Florence, South Carolina to Robbins (just east of Augusta, Georgia). It was built in the late 1800s and large parts of it were built by the Atlantic Coast Line's predecessor companies.^[1] Parts of the line are still in service.

The Florence—Robbins Line began in Florence, South Carolina at a junction with the Atlantic Coast Line's Main Line. From Florence, it ran west-southwest to Sumter, which was a hub for the company and a connection with some of their other lines.^[2]

From Sumter, the line continued southwest to Denmark and Cope before coming to an end at Robbins (just east of Augusta, Georgia), where it connected with the Charleston and Western Carolina Railway (an Atlantic Coast Line subsidiary).

The line's Creston Branch ran from the line at Creston east along the Santee River to Eutawville. From there, it turned south to Pregnall where it connected to the South Carolina Railroad.

The first segment of the Florence—Robbins Line was built from Florence to Sumter by the Wilmington and Manchester Railroad in 1853.^[3]

From Sumter to Denmark, it was built by the Manchester and Augusta Railroad. The Manchester and Augusta Railroad was chartered in 1870, but it was not completed until 1899.^[4] The Creston Branch was chartered and built by the Eutawville Railroad in 1885. The Manchester and Augusta Railroad gained ownership of the Eutawville Railroad in 1887 and by 1890, its name was changed to the Charleston, Sumter and Northern Railroad.^[5]

By the time it was complete in 1889, the Manchester and Augusta Railroad, along with the Wilmington and Manchester Railroad and the Charleston, Sumter and Northern Railroad, were all considered to be part of the group of independent railroads known as the Atlantic Coast Line. The lines were formally merged into the Atlantic Coast Line Railroad in 1898.^[4]

On June 30, 1899, the Atlantic Coast Line extended the line from Denmark south to connect with Charleston and Western Carolina Railway (C&WC) at Robbins.^[4] The C&WC was owned by the Atlantic Coast Line Railroad and operated as a subsidiary. By then, the Atlantic Coast Line classified the line from Florence to Robbins as their K Line and trains would continue from Robbins on the C&WC to Augusta, Georgia.

By 1949, the Atlantic Coast Line operated two daily passengers trains and two daily through freight trains on the line from Florence to Augusta. Additional local freight trains also ran the line from Florence to Sumter and from Sumter to Augusta as well. Local freight trains ran the Creston Branch six days a week at this time as well.^[2]

In 1959, the Atlantic Coast Line Railroad fully merged the Charleston and Western Carolina Railway into its network. The Atlantic Coast Line then annexed the former C&WC from Robbins to Spartanburg, South Carolina to the K Line, which then became known as the Florence—Spartanburg Line. The two daily passenger trains, one daily through freight, and other local freight trains continued to run from Florence to Augusta through the 1960s with separate freight trains running from Augusta to Spartanburg.^[6]

The Atlantic Coast Line became the Seaboard Coast Line Railroad (SCL) in 1967 after merging with their rival, the Seaboard Air Line Railroad (SAL). After the merger, the line from Florence to Augusta operated as their Augusta Subdivision. By 1971, only freight trains were operating on the line.^[7]

In 1980, the Seaboard Coast Line's parent company merged with the Chessie System, creating the CSX Corporation. The CSX Corporation initially operated the Chessie and Seaboard Systems separately until 1986, when they were merged into CSX Transportation. In the 1980s, CSX abandoned the line at the south end from just north of Robbins to Cope.^[8] Further north, CSX abandoned the line from Timmonsville to Lynchburg in 1989, which severed it as a through route from Florence to Sumter. Two years later, it was abandoned from Florence to Timmonsville. The segment from Sumter to Lynchburg was abandoned in 1992.^[9]