Should several Line Commissions be interested in some particular question concerning military movements by rail, the Chief of the General Staff can summon them to a joint conference as often as may be necessary. The fact, also, that the members of the Line Commissions are members of the Superior Commission assures co-ordination in the studies carried on as regards the railways in general, and provides a ready means by which the central body can obtain the information it desires concerning any one system or group of systems. As their district executives, the Line Commissions have such number of _Sub-Line Commissions_ as may be found necessary. Each of these is, in turn, composed of a military member, nominated by the Minister, and a technical member, chosen by the Line Commission. Then, also, to discharge the function of local executive, there is at every important centre of traffic a _Station Commission_ ("Commission de gare") which consists of a military officer and the stationmaster. It receives from the Line or Sub-Line Commission all orders or instructions concerning military transport to, from, or passing through, such station, and is the recognised intermediary for carrying them into effect and seeing that efficiency is ensured and good order maintained. A staff, formed of military men and railwaymen acting in combination, is allotted to each Line, Sub-Line or Station Commission. Concerning the representation of these two elements, military and civil, on the one body, article 10 of the decree of December 8, 1913, on Military Transports says:-- The special function of each of the agents, military or technical, on the Commissions or Sub-Commissions must, in the operation of the service, be maintained in the most absolute manner. At the same time these agents should not lose from their view the fact that their association is designed to effect harmony between the exigencies alike of military requirements and of rail transport, subordinating those of the one to those of the other, according to circumstances.