. As chief engineer of the Army of the Cumberland, he achieved recognition by restoring a supply line that saved that army from starvation and surrender, known the “Cracker Line”, that helped Union troops to success in the Chattanooga Campaign in the autumn of 1863. Leading the first operation against Petersburg, Smith’s hesitation, possibly illness-related, cost the Union a prime opportunity for a quick end to the war, and he was relieved of command.