In the fall of 1863 and the winter of 1864, as narrated in the "Medical and Surgical History of the War of the Rebellion," the chief army of the West was concentrated principally along the line of railroads leading from Nashville, Tennessee, to the South-west, viâ Chattanooga, Tenn., and onwards towards Atlanta, Georgia. At the outset the sick and wounded who could travel in ordinary passenger cars to points in the North were so taken. Severe cases had to remain in the nearest available hospital depôt. In addition to the discomfort suffered by the former in having to travel in cars not suited to invalids, they were liable to frequent and prolonged delays on the single-track lines by reason of the constant passing of supply trains proceeding to the front; and not unfrequently the detentions were at points where nothing could be obtained for feeding the sufferers or making them comfortable, while even if rations could be drawn the train afforded no means of cooking them. So it was resolved to have a train which would be the equivalent of an ambulating, self-contained hospital, capable of carrying both recumbent and sitting-up patients and supplying all their wants on the journey. On August 11, 1863, instructions were sent from the Assistant-Surgeon-General's Office to the Medical Officer of the Army of the Cumberland directing him "to take immediate measures to fit up a special train for hospital purposes, with every possible comfort," to run between Nashville, Ten., and Louisville, Ken. General Thomas, in turn, accorded the fullest authority to the Medical Officer to select for the purpose the best locomotives and the best cars to be found among the railway rolling stock, and to have new cars fitted up whenever necessary. He further directed that the most experienced drivers, conductors and other necessary railway employés should be selected for the conduct of the hospital-train service.