In regard to the Transportation Department, it may be of interest to state that this was placed by McCallum in charge of a General Superintendent of Transportation on United States Railroads in the Military Division of the Mississippi. For each of the principal lines there was appointed a Superintendent of Transportation who, acting under the control of the General Superintendent, was held responsible for the movement of all trains and locomotives; and these superintendents, in turn, had under their direction one or more Masters of Transportation, whose business it was to be constantly moving about over the sections of line placed under their charge, and see that the railway employés were attending properly to their duties. At each of the principal stations there was an Engine Dispatcher who was required to see that the locomotives were kept in good order and ready for immediate use whenever required, to exercise control over the drivers and firemen, and to assign the requisite "crew" to each engine sent out. Maintenance of road and structures for each line (as distinct from the reconstruction work left to the Construction Department) was in charge of a Superintendent of Repairs, assisted by such supervisors, road-masters and foremen as he needed to control and direct his working staff; and maintenance of rolling stock was delegated to (1) a Master Machinist, responsible for repairs to locomotives, and (2) a Master of Car Repairs. These various officers were independent of each other, and all of them reported direct to the General Superintendent. The maximum force employed at any one time in the Transportation Department of the Military Division of the Mississippi (as distinct from the military lines in Virginia and elsewhere) was about 12,000 men. A sufficient staff of competent railwaymen for the operation of the Military Railways was difficult to get, partly because of the inadequate supply of such men in the United States at that period, and partly because those still at work on railways not taken over for military purposes were unwilling to give up what they found to be exceptionally good posts; but of the men whose services he was able to secure McCallum speaks in terms of the highest commendation. Having got his Department and Construction Corps into working order, McCallum had next to turn his attention to ensuring an adequate supply of locomotives and cars, with the necessary shops, tools and materials for keeping them in working order. Here the Secretary of War again came to his help, issuing, on March 23, 1864, an Order addressed to locomotive manufacturers in which he stated that Colonel McCallum had been authorised by the War Department to procure locomotives without delay for the railways under his charge, and proceeded:--