Union battery wagon
This Union battery wagon?an ambulance converted to transport heavy telegraph batteries? was photographed at Petersburg, Va. The military telegraph made large-scale troop movements possible for both South and North, including the transfer of 23,000 Federals from Bristoe Station, Va., to Chattanooga, Tenn., about 1,233 miles, in just 11 1/2 days after the Battle of Chickamauga.

Image: Library of Congress