FOLLOWING DEFINITIVE field surgery, the large volume of Civil War casualties dictated relatively swift transfer to a base or general hospital. These institutions were situated in major urban areas and provided a final health care facility for hundreds of thousands of injured and seriously wounded. In many instances, the wounded and postoperative patients were taken from the field hospitals and loaded onto the floors of railroad freight cars, which were covered with layer upon layer of straw. These trains were marked, in enormous red letters, "US Hospital Train," and the locomotive, boiler, and tender were also painted red. After the dreadful horrors of the field hospital and the painful, lurching journey aboard a hospital train or steamboat, the general hospital proved to be a godsend to the wounded.
Rutkow IM. Base or General Hospitals During the Civil War. Arch Surg. 1999;134(9):1021. doi:10.1001/archsurg.134.9.1021