A.—Advantages
Assuming (1) the provision, in advance, of a system or systems of railways capable of meeting all the requirements of the military situation on the outbreak of war, or (2) the possibility of constructing military railways during the progress of hostilities, such railways should permit of—
A mobilisation of troops and their concentration at the frontier, or at the seat of war, with a speed that was impossible under earlier conditions.
Simultaneous use of different routes across the national territory for concentration either on the frontier or at a point some distance therefrom where the concentration can be completed without fear of interruption by the enemy.
Sudden invasion of neighbouring territory by troops sent in a succession of rapidly-following trains direct from various points in the interior of the country where they might have been concentrated without the knowledge of the enemy, this procedure being adopted in preference to collecting at the frontier in advance a force on such a scale as would disclose prematurely the intentions entertained.
The possibility of using promptly, for these purposes, the full strength of the country's available resources—the railway lines in the interior having already been adapted thereto, as well as those on or directly connecting with the frontier—with a proportionate increase of the offensive and defensive power of the State.
The supplementing of increased mobility and celerity by decreased strain on the physical powers of the troops and the avoidance of such inevitable reduction in their numbers as would result from the trials and fatigues of prolonged marches by road (in combination with the carrying of kits, etc.), should railway lines not be available.
A further consequent increase in the fighting strength of the army.
The possible attainment of the power of initiative through an early concentration of large forces at points of strategic importance either on national or on enemy's territory.[78]
The carrying out of strategical combinations on a scale or of a character which would formerly have been impracticable.
Employment of railways for tactical purposes during the progress of a war, including therein (a) movement of troops from one part of the theatre of war to another, whether with a view to effecting big changes of front or otherwise; (b) employment of the same Army Corps on different fronts in succession, their transfer being effected in the briefest possible interval of time; (c) the rapid bringing up of reinforcements at a critical moment to some position exposed to overpowering attack which might otherwise be lost; (d) surprise attacks on the enemy; (e) the throwing of great masses of troops on distant points; (f) strengthening weak places in the fighting line; (g) strengthening threatened forts by means of troops, guns, munitions or supplies; (h) relief of invested fortresses, and (i) retirement by rail—when circumstances permit—of troops after defeat.
Control of a line of rail communication between the base and the strategic centre of operations, facilitating the enormous amount of transport in both directions which must be kept up in the rear of the army, and for which the elements of speed, safety and regularity may be of vital importance.
The possibility, thanks to railways, of regarding the whole interior of the national territory as a base for the supply of requirements at the front, dependence having no longer to be placed on a base established in one particular district with its restricted range of possible supplies and its collection of magazines, stores, workshops, transport parks, etc., protected by fortresses, entrenched camps, or other means of defence.
The establishment of supplementary, sectional or advanced bases along the line of communication, with railway services so arranged that supplies can be dispatched daily in such regulated quantities, and to such points, as will serve the immediate needs of the army in the field, without risk either of shortage or of excess.
Avoidance, under these conditions, of congestion of the railway lines in the immediate rear of the army by trains or loaded wagons containing a redundancy of supplies which (a) cannot be unloaded, (b) restrict the use of the lines for other purposes, and (c) might have to be abandoned to the enemy in the event of a sudden retreat.
Material benefits from the substitution of rail for road transport of food, etc., by reason of (a) greater speed and regularity; (b) less risk of deterioration from exposure to weather, and other causes; (c) decreased cost of transport as compared with earlier conditions involving the employment of a greater number of drivers, escort, guards, horses and road vehicles; and (d) the arrival at destination of the full quantities dispatched, the need for the consumption of an appreciable proportion en route by men and animals in a convoying wagon train, carrying supplies for long distances by road, being non-existent.
Reduction in the need for field ovens and other paraphernalia of the army cook, since much of the food required—bread, for example—can be prepared in cities or elsewhere at a distant base and forwarded regularly by rail.
Freedom, more or less complete, from the once prevalent obligation on the part of an advancing army that it should "live upon the country"—a condition which the enormous increase in the size of armies to-day would render impossible of fulfilment, even assuming that the people of the country invaded had not withdrawn live stock, vehicles and food supplies on their retirement before the invader.
In addition to this provision for the wants of an army in its advance into hostile country, the safeguarding of the troops against the risk of their becoming a band of demoralized marauders, wandering over a wide area to seek and appropriate food whenever they can find it—as was the case, for instance, in the Napoleonic wars—the maintenance of discipline and the continued usefulness of the troops as a concentrated body for the military purposes in view being further assured when both men and leaders are relieved of anxiety as to the continuance of their supplies.
The conduct of war at a great distance from the base by reason of the facilities offered for the forwarding alike of troops, reinforcements, supplies and military materials, the value of even a single line of railway in the achievement of this purpose having been incontestably established.
Defence of frontiers by strategical railways which may, also, become available for general use.
Investment of cities or fortresses in occupied territory when, owing to the lack or the deficiency of food supplies in the surrounding country, the troops engaged are mainly if not entirely dependent on those brought to them by rail from their own base.[79]
Victualling of cities before, and their revictualling after, investment.[80]
Extension of lines of communication by means of quickly-constructed narrow-gauge siege railways to be operated by motor traction, animal power, or otherwise, including therein trench tramways for (a) removal of wounded men from the trenches; (b) transport of siege guns to trenches; and (c) supplying ammunition to battery.
Transport of heavy siege guns, mortars, ammunition and other materials of a size or weight that would render impracticable their conveyance, whether singly or in the aggregate, along ordinary roads, the railway offering, in this respect, facilities for ponderous transport comparable to those of the steamship, with the further advantage of being able, in most instances, to take the guns, etc., to the spot or to the locality where they are wanted.
Material aid given to expeditions to countries otherwise devoid of means of communication, by the construction of military railways.
Employment of armoured trains which, apart from their usefulness in defending railways against attack, may, as movable fortresses, render important service in the operations against the enemy.
Removal of sick and wounded from the theatre of war, and the ensuring of their distribution among hospitals in the rear or throughout the interior, thus (a) avoiding alike the embarrassment to the army and the many dangers and evils that would result from their remaining in overcrowded hospitals on or near the battle-field; (b) giving the men a better chance of effecting a speedy recovery and returning soon to the ranks; and (c) adding to the fighting strength of the army by the combination of these two advantages.
Facilities for giving a short leave to officers and men who, though neither sick nor wounded, have been so far affected by their strenuous exertions that they stand in need of a rest, or change, for which they will fight all the better subsequently.
Dispatch of prisoners of war into the interior by trains which have brought reinforcements or supplies, the army thus being speedily relieved of what might otherwise be a hindrance to its operations.
Return of material no longer wanted at the front and constituting impedimenta of which it is desirable to get rid as soon as possible.
Conveyance into the interior of "trophies of war"—including plunder—taken from captured towns or cities.
Retirement of troops from occupied territory on the declaration of peace.