This primary source comes from the Records of the Office of the Chief of Engineers.
National Archives Identifier:
282335Full Citation: Photograph with caption 'Excavator on Mile 52 being pulled by traction-engine, plow side. August 8, 1904; 8/8/1904; Records of the Office of the Chief of Engineers, Record Group 77. [Online Version, https://docsteach.org/documents/document/photograph-with-caption-excavator-on-mile-52-being-pulled-by-tractionengine-plow-side-august-8-1904, May 9, 2024]