In the fall of 1863 the Confederate railroads, acting as interior lines of communication, transferred two divisions and an artillery battalion of Lieutenant General James Longstreet’s I Corps, Army of Northern Virginia, by railroad from Virginia to Georgia to reinforce General Braxton Bragg’s Army of Tennessee. The troops began arriving at the Catoosa Platform, Georgia on September 19, having begun their journey from Virginia on September 9. Ultimately, only 5 of Longstreet’s 10 infantry brigades arrived in time to participate in the Confederate victory at Chickamauga. Following their defeat, the troops of MG William Rosecrans’ Army of the Cumberland fell back to Chattanooga, Tennessee where they were surrounded by the Confederates who occupied the heights surrounding the town.