In 1862, the Secretary of War called on Haupt to assist in the reconstruction of railroads destroyed by retreating Confederates. Haupt was able to both rebuild the rail system and organize an efficient rail operation to resupply the Union. In nine days, using troop labor, Haupt rebuilt the Potomac Creek Bridge which had originally taken one year to build. Visiting the site of Haupt's astounding accomplishment, President Lincoln reported to his cabinet that the bridge was "The most remarkable structure that eyes ever rested upon. That man Haupt has built a bridge across Potomac Creek, about 400 feet long and nearly 100 feet high, over which loaded trains are running every hour, and, upon my words, Gentlemen, there's nothing in it but bean poles and cornstalks."
Herman Haupt, 1817-1905
After graduating from West Point, Herman Haupt went to work for the railroad industry. Haupt rapidly rose in the profession. During the Civil War, Haupt served as Chief of Construction and Transportation for the US Military Railroad System. After the war, he served as General Manager/Chief Engineer of the Shenandoah Valley, the Richmond and Danville, and the Northern Pacific Railroads, and as President of the Dakota and Great Southern Railroad.
The Bunker Hill covered bridge is the only remaining example in the world of the Haupt Truss in wood.
In 1851, Haupt published General Theory of Bridge Construction, detailing his patent (Dec. 27, 1839, Improving on the Lattice Truss). Haupt wanted to discover formulae for determining weight distribution and capacities of bridges. His book detailing his discoveries of a decade earlier became a standard civil engineering text at the main engineering schools of the era.