encirclement to cut it off from supplies and reinforcements, then would follow artillery bombardment and direct assault by massed infantry. However, Chattanooga's natural water and mountain barriers to its east and south made this nearly impossible with the forces that Mitchel had available. When the Union Army threatened Chattanooga, the Confederate States Army would (from its naturally protected rear) first reinforce Chattanooga's garrison from Atlanta. When sufficient forces had been deployed to Chattanooga to stabilize the situation and hold the line, the Confederates would then launch a counterattack from Chattanooga with the advantage of a local superiority of men and materiel. It was this process that the Andrews raid sought to disrupt. If he could somehow block railroad reinforcement of the city from Atlanta to the southeast, Mitchel could take Chattanooga. The Union Army would then have rail reinforcement and supply lines to its rear, leading west to the Union-held stronghold and supply depot of Nashville, Tennessee. Planning James J. Andrews, a civilian scout and part-time spy, proposed a daring raid to Mitchel that would destroy the Western and Atlantic Railroad as a useful reinforcement and supply link to Chattanooga from Atlanta and the rest of Georgia. He recruited the men known later as the Andrews Raiders. These were the civilian William Hunter Campbell and 22 volunteer Union soldiers from three Ohio regiments: the 2nd, 21st, and 33rd Ohio Infantry. Andrews instructed the men to arrive in Marietta, Georgia, by midnight of April 10, but heavy rain caused a one-day delay. They traveled in small parties in civilian attire to avoid arousing suspicion. All but two (Samuel Llewellyn and James Smith) reached the designated rendezvous point at the appointed time. Llewellyn and Smith joined a Confederate artillery unit, as they had been instructed to do in such circumstances. Andrews' proposal was a combined operation; General Mitchel and his forces would first move on Chattanooga; then, the Andrews’ Raid would promptly destroy the rail line between Chattanooga and Atlanta. These essentially simultaneous actions would bring about the capture of Chattanooga. Andrews' Raid was intended to deprive the Confederates of the integrated use of the railways to respond to a Union advance, using their interior lines of communication. The plan was to steal a train on its run north towards Chattanooga, stopping to damage or destroy track, bridges, telegraph wires, and track switches behind them, so as to prevent the Confederate Army