Final answer:
Railroads and trains were considered one of Lincoln's hidden weapons during the war.
Step-by-step explanation:
During the war, one of Lincoln's hidden weapons was the use of railroads and trains. They played a crucial role in the transportation of troops, supplies, and information. The Union's extensive railroad system allowed for quick mobilization and reinforcement, giving them an advantage in the war.
Learn more about Lincoln's hidden weapons during the war