One of the finest examples of the engineer's mettle during the war was demonstraded during the Stones River campaign at Lavernge, Tenn. Col. Innes and the 390 of his men were guarding Gen. Rosecran's lines of commincations and supply when they were assailed by Confederate Gen. Joe Wheeler's entire cavalry division.
Outnumbered 10 to (?), the engineers withstood seven assaults without breaking and threw Wheeler's demand for surrender back in his face with the retort, "We don't surrender much".
And they didn't.