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. An Act of Congress of 31 January 1862 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 Transportation Corps is a combat service support branch of the U.S. Army. It is responsible for the movement of personnel and material by truck, rail, air, and sea. It is one of three U.S. Army logistics branches, the others being the Quartermaster Corps and the Ordnance Corps. The Corps was established in its current form on 31 July 1942, with predecessor services dating back to the American Civil War. The Transportation Corps is currently headquartered at Fort Gregg-Adams, Virginia. The officer in charge of the branch for doctrine, training, and professional development purposes is the Chief of Transportation (CoT) and Commandant of the US Army Transportation School, currently held by BG Beth A. Behn. The Corps's motto is "Nothing Happens Until Something Moves".