The short answer to this important question is that Southern railroad companies owned many slaves and built most of their lines with enslaved labor. The question, however, has not been fully researched and for years we have known little about this experience or the scale of the railroads’ involvement in slavery. We know that southern slaveholders were the principal stockholders and directors of many railroad companies and that the South moved quickly in the 1830s to build railroads. Southerners built some of the earliest and longest railroads in the nation. By the 1850s southern railroad construction was in full swing, with crews grading thousands of miles of track.
Although historians, such as Allen Trelease, Robert Starobin, and Walter Licht, have acknowledged the presence of slave labor on Southern railroads, we have little sense of its overall dimensions or its relationship to southern expansionism of the 1850s. One historian, Theodore Kornweibel, has recently begun to research in detail the southern railroads’ use of slave labor. Kornweibel found documented evidence for slave labor on over 75 % of southern railroads. He has also estimated that over 10,000 slaves a year were working on the railroads in the South between 1857 and 1865. These figures seem entirely plausible and accurate.
A careful examination of railroad annual reports from the South begins to reveal the scale and diversity of the experience. Most of the slave labor on southern railroads was hired or rented from local slaveholders to grade the tracks. Enslaved women and children were also forced to work on the railroads, running wheelbarrows, moving dirt, cooking, picking up stones, and shoveling. Some skilled slaves, especially blacksmiths, were hired as well on these construction crews.
But railroads began buying slaves outright in the mid-1850s. Only after the Civil War did these railroads have to reconcile their assets and liabilities to account for the loss of slavery. The Nashville and Chattanooga Railroad President, for example, reported after the Civil War on the railroad’s investment in slaves. “We find from the books,” he explained to the stockholders, “that there has been invested in negroes, in Georgia, the sum of $154,348 and negroes sold amounting to $32,805.25 leaving negro investment $121,542.71.” The investment, he noted, “is now, manifestly, a total loss.”
Railroads, it seems, bought slaves both in large groups and one at a time. The Richmond and Petersburg listed 114 “slaves” on its payroll of 191 employees in 1864. The railroad purchased its first slave in 1856 for $1,070, listing the expense in its annual report as “a negro man purchased.” By 1860 some railroads were buying slaves by the dozens. The Mississippi Central bought 21 slaves in one purchase and 31 in another in 1860. 
Its 1864/65 annual report from the company treasurer listed in the balance sheet on the liabilities side “Account and Bonds of C. S. and cost of Negroes now free $585,237.” In an action that clearly indicated the intentions of the slaveholding railroads, the Louisville, Cincinnati and Charleston directors authorized a large purchase of slaves in 1841. The chairman of the board, Alexander Mazyck, proposed a resolution that the Board “be authorized as soon as the means and credit of the Company will permit, to purchase for the service of the Rail-road, from fifty to sixty male Slaves between the ages of sixteen and thirty.” It was adopted without argument or amendment.
Railroads in the South owned and hired slaves on a scale we have generally forgotten. By the 1860s the Southern railroads were among the largest slaveholding and slave employing entities in the region, as a group they eclipsed the largest individual planters. Recent historical research has begun to uncover just how far the practice extended. The implications of this form of slavery, however, need further examination. We need to know more about the use of slaves by railroads, the jobs they performed, and their experiences.