How did railroads supply armies during the American Civil War?

During the American Civil War, railroads played a critical role in military logistics by enabling the rapid movement of troops and the long-distance transport of bulky freight. By facilitating these large-scale shipments, railroads were essential in sustaining the forward movement of armies throughout the conflict.1

The Union held a significant logistical advantage, possessing more than 70 percent of the nation's railroads at the time. To manage these complex operations effectively, military commanders utilized the telegraph as an indispensable tool for operational coordination and the control of rail traffic. While railroads were the primary means of land movement for supplies and personnel, they were complemented by river steamboats, which also served an essential role in supporting military efforts during the war.21