 During that year as a general, however, he made an enormous impact on the Union war effort.The Civil War was one of the first wars in which large-scale railroad transportation was used to move and supply armies rapidly over long distances.Haupt assisted the Union Army of Virginia and Army of the Potomac in the Northern Virginia Campaign, the Maryland Campaign, and was particularly effective in supporting the Gettysburg Campaign, conducted in an area he knew well from his youth.