In addition to making traffic arrangements and undertaking the operation of those lines at the theatre of war that may pass under full military control, the Field Line Commissions are required to carry out such construction, repair, maintenance or destruction work on the railways as should be found necessary.
On the _Lines of Communication_ passing through the two zones and ensuring direct communication between the interior and such accessible points on the railway as may, from time to time, be nearest to the armies in the field, the leading stations _en route_ are required to serve a variety of military purposes; though in each and every such instance the system of organisation is such that the duties to be discharged or the responsibilities to be fulfilled are undertaken by, or are under the control of, a Commission formed on the now established basis of representation thereon of both the military and the technical elements.
For the conveyance of troops, there are, in the first place, _Mobilisation Stations_ and _Junction Stations_, whence the men within a certain district are sent to the _Embarkation Stations_, at which complete units for the front are made up. These are followed by _Stations for Meals_ ("Stations haltes-repas"), for men and horses; though in this case the "stations" may really be goods or locomotive sheds, able to accommodate a large number of men. At the end of the railway line, so far as it is available for troops, come the _Detraining Stations_.
In regard to supplies and stores, the first link in the chain of organisation is constituted by the _Base Supply Stations_ ("gares de rassemblement"). Here the supplies going from a certain district outside the theatre of operations to any one Army Corps must be delivered; and here they are checked, made up into full train loads, or otherwise dealt with in such a way as to simplify and facilitate their further transport.
In certain cases full train-loads arriving at these assembling stations pass through to destination, after being checked; but the general practice is for the consignments forwarded from base supply stations to go to the _Supply Depôts_ ("Stations-magasins"), serving the purposes of storehouses from which supplies, whether received from the base or collected locally, can be despatched in just such quantities, and at just such intervals, as circumstances may require. These depôts are organised on a different basis according to the particular service or purpose for which they are designed,--Cavalry, Engineers, Artillery, Medical, Telegraph Corps; provisions, live stock, clothing, camp equipment, etc. Their number, character, and location are decided by the Minister of War in time of peace. On the outbreak of war those in the Zone of the Armies pass under the control of the Commander-in-Chief together with the railway lines within that zone. The situation of the depôts may be changed, or additional depôts may be opened, by the Directeur de l'Arrière, with the consent of the Commander-in-Chief.