In making the necessary preparations, in time of peace, to ensure the successful realisation of these and other purposes, there is a vast amount of work that requires to be done. In readiness for the excessive strain that will be thrown on the railways as soon as they pass from a peace footing to a war footing, on the order being given for mobilisation, the military authorities and the railway authorities must needs have at their command the fullest information as to the physical conditions, the resources and the transport capabilities of every line of railway in the country which, directly or indirectly, may be able to render useful service. Details as to double or single track; gradients; number of locomotives, carriages, wagons, horse-boxes and other vehicles available; and facilities afforded by stations in important centres as regards number and length of platforms and sidings, water supply, loading, unloading or storage accommodation, etc., are all carefully compiled and kept up to date. As regards rolling stock, lines not likely to be called upon to carry any military transports at all may still be able to contribute to the supply of carriages and wagons wanted to meet the heavy demands on other railways. By including all lines of railway in the collected data, it will be known exactly where additional rolling stock may be obtained if wanted. The carrying capacity of the different types of carriages, trucks, etc., is also noted. If necessary, arrangements will be made for the reduction of gradients, the improvement of curves, the construction of connecting links between different main lines, the lengthening of station platforms, or the provision of increased loading or unloading facilities. On the basis of the information collected elaborate calculations are made in regard to such matters as (1) the number of vehicles required for a given number of men, with horses, guns, munitions, stores, road vehicles, etc., so that rolling stock can be used to the best advantage and according as to whether the troops carried belong to the Infantry, Cavalry or the Artillery; (2) the number of vehicles that can be made up into a train going by any one route; (3) the length of time likely to be taken for the entraining and detraining respectively of a given unit; (4) the time intervals at which a succession of troop trains can follow one another on the same line; (5) the speed of troop trains; and (6) the further intervals to be allowed in the arrival at one and the same station, or centre, of a number of trains starting from different points, so as to avoid the risk of congestion and of consequent delays.