United States Military Railroad

United States Military Railroad
Orange & Alexandria Railroad rail yard in Alexandria, Virginia
Active	February 1862 – 1865
Country	United States of America
Branch	United States Army
Type	Transportation
Role	Strategic movement, operational resupply
Nickname(s)	"USMRR"
Commanders
Notable commanders	Daniel McCallum

The U.S. Military Railroad (USMRR) was established by the United States War Department as a separate agency to operate any rail lines seized by the government during the American Civil War. The United States Congress authorized President Abraham Lincoln to seize control of the railroads and telegraph for military use in January 1862. In practice, however, the USMRR restricted its authority to Southern rail lines captured in the course of the war. As a separate organization for rail transportation the USMRR is one of the predecessors of the modern United States Army Transportation Corps.

The American Civil War was the first war where railroads were a significant factor in moving troops and supplying forces in the field. The United States Military Railroad organization was established to coordinate this new capability for the Union Army. The USMRR organization benefited from the appointment of experienced railroad men from the private sector. Thomas A. Scott, vice-president of the Pennsylvania Railroad (PRR), served as an Assistant Secretary of War during the period 1861–1862. In January 1862 Scott prepared a report on military transportation that anticipated the creation of the USMRR.Daniel C. McCallum, former general superintendent of the New York and Erie Railroad, was appointed as Military Director and Superintendent of U.S. Railroads.Herman Haupt, former chief engineer of the PRR, was appointed as Chief of Construction and Transportation in the Virginia theater. The departments in the USMRR tended to operate autonomously, although micromanagement from the Secretary of War and overlapping authority between departments did affect their operations. Over time the USMRR would buy, build or capture 419 locomotives and 6,330 cars beyond the rolling stock that was requisitioned from the various Northern railroads. When Col. McCallum was first appointed the USMRR system consisted only of 7 miles of the Washington and Alexandria Railroad; however, by war’s end the USMRR exercised control over a network of more than 2,000 miles of military railroads and captured Southern rail lines.