NARA Collection gross — Collection gross

This file unit contains a telegram from General George Meade to Colonel McCallum, signaling that the 12th Corps is ready at Brandy Station for rail mobilization.

This file contains telegrams from the Superintendent at Baltimore and Ohio Railroad, William Prescott Smith, to Colonel McCallum, with real-time updates on the first large scale troop mobilization of the war.

This file unit contains a draft of the organization chart describing the future United States Military Railroad structure by Daniel Craig McCallum.