General Herman Haupt

Picture
As a Union Army general in the American Civil War, he revolutionized military transportation, organization of the U.S. Military Railroad, in the United States and was one of the unsung heroes of the war.

Thaddeus S.C. Lowe

Picture
Thaddeus S.C. Lowe was an American aeronaut who attempted to cross the Atlantic and also introduced the use of balloons into the U.S. Civil War. this invention helped a lot on enemy troops.

Andrew Carnegie

Picture
 Through Andrew Carnegie was obtained the force which opened the War Department Telegraph Office; which speedily attained national importance by its remarkable work, and with which the memory of Abraham Lincoln must be inseparably associated. It was fortunate for the success of the telegraphic policy of the Government that it was entrusted to men of such administrative ability as Colonel Anson Stager, E. S. Sanford, and Major Thomas T. Eckert. The selection of operators for the War Office was surprisingly fortunate, including, as it did, three cipher-operators-D. H. Bates, A. B. Chandler, and C. A. Tinker-of high character, rare skill, and unusual discretion.

John Ericsson

Picture
Naval engineers of the 1860's were given the assignment of building ships that could withstand the cannonballs of artillery.  Two of these were the Merrimac and the Monitor.  Both would end up in battle and history was made.  Present-day modern ships are the result of the invention of the iron ship in the 1860's.