Near the end of the bloodiest day in American military history at the Battle of Antietam on Sept. 17, 1862, Union Army commander General George B. McClellan telegraphed Army Headquarters in Washington, DC, requesting 20-pound Parrott ammunition be sent through that night by way of Hagerstown and Chambersburg to his forces near Sharpsburg, MD. His request led to a high-speed resupply run down the Cumberland Valley Railroad. A four-car powder train traveled 40 miles from the arsenal in Washington, now Ft. McNair, to Baltimore's Camden Station, then was pulled by horse two miles to Bolton Station before continuing 84 miles toward Harrisburg on the Northern Central Railroad in 2 hours 53 minutes. At the train yard in Bridgeport, now Lemoyne, PA, the Cumberland Valley Railroad engine Judge Watts took over and a fifth ammunition car was added. The final 74-mile run to Hagerstown averaged 37 mph, including 10-minute stops in Shippensburg and Chambersburg to cool the wheels, while the train's average running speed was 45 mph and Judge Watts pulled at 55 mph much of the way, an almost unheard-of speed at the time. Although Sharpsburg lay only 70 miles from Washington by wagon, routing the ammunition 200 miles by rail from Washington to Bridgeport and then to Hagerstown demonstrated the logistical advantages of railroads and established the Cumberland Valley Railroad as a pivotal Union supply route for the rest of the war. Mary Emma Hollar, who lived on Railroad St., now Earl St., in Shippensburg in 1862, later recalled the thunder of the ammunition train rushing to supply the troops at Antietam; she was a devoted Union patriot who provided bandages and surgical supplies to the troops, and her husband Gideon Weidman Landis, a Civil War veteran, served in Co. H, 9th Regimental Cavalry, the 92nd Volunteers, also known as the Lochiel Cavalry.