During the Civil War, this stretch of railroad formed a vital Federal transportation link between steamboats at Johnsonville on the Tennessee River and the major Union base at Nashville. W.H. Crutcher had purchased 533 acres and built a sixteen-by-sixteen-foot log structure here in December 1860. After occupying the region in the spring of 1862, Union officers seized the Nashville and Northwestern Railroad to Kingston Springs and planned to extend the tracks to Johnsonville, completing the line two years later as a Federal military railroad. Free blacks and former slaves impressed by the Union Army built the railroad, while the 12th and 13th U.S. Colored Troops Infantry Regiments defended it against Confederate cavalry and guerrilla attacks. Its 78 miles became especially important after Confederate Gen. John Hunt Morgan burned the south tunnel of the Louisville and Nashville Railroad in Sumner County, delaying southbound Federal supplies to Nashville. After the military railroad was completed in 1864, supplies moved by ship to Johnsonville, then by rail through Mile Post 42, present-day Dickson, to Nashville, Chattanooga, and Atlanta.