Grant's success in the initial assaults on Petersburg in June 1864 and in the siege that ensued over the next nine-and-half months were dependent on the Union army's ability to move troops and to move supplies quickly and efficiently.

Union engineers were critical to the Union army's movement south of the James River for a surprise attack on Petersburg.

The Military Railroad Construction Corps' work was equally critical in supplying Union forces who fought along a front that stretched for over 30 miles.