This primary source comes from the Records of the Office of the Chief Signal Officer.
National Archives Identifier:
525099Full Citation: U.S. Military Engine. 'Lincoln's Coach'; ca. 1860 - 1865; Mathew Brady Photographs of Civil War-Era Personalities and Scenes, 1921 - 1940; Records of the Office of the Chief Signal Officer, Record Group 111. [Online Version, https://www.docsteach.org/documents/document/us-military-engine-lincolns-coach, March 15, 2025]