The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 5: Forts and Artillery.
Francis Trevelyan Miller, Ed.

[284] for railroad use, Colonel Haupt stated that, even if a wire and operators were provided for the exclusive use of the road, the line would be so liable to derangement from storms and other causes that it could be considered only as a convenience or an auxiliary. As a principal or sole means of operation it was highly unreliable, and was not a necessity.

In order, then, to get some kind of service, the use of the telegraph had again to be abandoned, and even a schedule was dispensed with. Trains received orders to proceed to Front Royal with all speed consistent with safety, returning trains to give the right of way, and all trains to send flagmen in advance. These flagmen were relieved as soon as exhausted. The trains were run in sections, and after considerable experience in this method of operation, a certain measure of success was obtained.

McDowell's orders had been to intercept Jackson; he had personally hurried through Manassas Gap with the troops in advance, and was at Front Royal when, on May 31st, an engineer officer reported to him that there was a bad break in the railroad just west of the summit of the gap, with the track torn up and rails and ties thrown down the mountainside. McDowell sent a hurried note to Haupt, who was east of the gap, and he replied by the same messenger that the general need feel no uneasiness, for, if the rails were within reach, the break could be repaired in a few hours. On June 1st, soon after daylight, the men of the construction corps reached the scene of the wreck and found it in bad shape, but set to work immediately. The broken cars were tumbled over the bank in short order. The track gang was divided into two parties, working toward each other from the ends of the break. The rails and ties were hauled up from the side of the mountain below, and by ten o'clock an engine passed over and was sent to report to General McDowell. Notwithstanding the quick work done throughout, Jackson escaped up the Valley, and the pursuit was fruitless.