C.—Limitations in Usefulness
The usefulness of railways in war is limited by the following considerations, among others:—
Railways are "inferior to ships in power of simultaneously transporting heavy loads" (Von der Goltz). For this reason an overland route to India could never compete, in respect to military transport, with the sea route via the Suez Canal. Such overland route, also, passing through foreign countries, would be especially liable to attack and interruption. Where, however, the overland route goes entirely through national territory (as in the case of the Trans-Siberian Railway), and when the questions of time and safety, in regard to an alternative sea route, suggest possible disadvantages, railways will be preferred to ships in spite of the said inferiority.
Railways are inferior to roads in so far as, like rivers and canals, they are on fixed spots. Troops depending on them are thus able to move only in the direction in which lines have been or can quickly be laid, whereas if they went by road they might have a greater choice of alternative routes.
For these reasons the choice of the zone of concentration or of the "decisive points" may depend less to-day on political, military or geographical reasons (as in the Napoleonic wars) than on the direction, extent and capacity of the available railways.
Great masses of troops can be entrained only at stations where facilities for their so doing have been prepared in advance. The provision of these facilities is even more necessary in the case of Cavalry or Artillery than in that of Infantry. Hence the movement of considerable bodies of troops may be restricted to certain lines, and their entrainment or detrainment even to certain large stations. In the case of road marching these restrictions would not apply.
Vehicles specially constructed for the purpose can alone be used on railways. Any deficiency in their supply must needs cause delay.
During the time the troops are travelling by railway their power of resisting attack is much more restricted than it would be if they were marching by road, they can do little or nothing to protect the railway lines, while if the enemy can only get to the railway he may be in a position to prevent the train from continuing its journey, and take the troops in it at a disadvantage.
For these reasons, among others, troop movements by rail at the theatre of war, and especially in the enemy's country, are attended by a degree of risk which may render it desirable to abandon the use of the railway for the time being.
Railways are especially liable to destruction by the enemy, and, although the arrangements made in advance may permit of speedy repairs or reconstruction, the interruption of traffic for even a day or half a day may be a matter of grave importance during the concentration of the army or at some critical moment.
Destructions of line carried out by a retreating force, in order to delay pursuit by the enemy, will be to the disadvantage of that force when, after having driven back the enemy, it would itself make use of the line it had rendered unserviceable.
Dependence on the railway for the transport of considerable bodies of troops on short journeys—say for twenty, twenty-five or thirty miles—is rendered inexpedient by the fact that, when allowance is made for the time likely to be taken, not only on the journey, but in the assembling at the station, in the entraining and detraining (perhaps at some place devoid of adequate platform or siding accommodation), and in the march from the arrival station to destination, it may well be found that the troops could cover the distance in less time by road, apart from the consideration, suggested above, as to their being in a better position, when marching, to resist attack. Experts in all countries have studied this question with a view to deciding, on the basis of their national conditions, within what limit it would be better for troops to march by road in preference to going by rail.
For reasons akin to those here stated, supplemented by the recent great expansion of motor transport, less has been heard of late concerning the proposed construction in this country of strategical railways along a coast-line remarkable for its sinuosities, and presenting, therefore, an exceptional position from the point of view of coast railways for purely defensive purposes.
As regards long-distance journeys, whilst armies marching by road have often been materially reduced in proportions by the number of men falling out owing to lameness, exhaustion, or other causes, those who reached the theatre of war, representing "the survival of the fittest," were better able to endure the trials and fatigues of the subsequent campaign than if they could have made the journey by rail under conditions involving no strain, but affording them no such exercise and strengthening of their physical powers.[81]
Experience has further shown that exceptionally long railway journeys may have a prejudicial effect upon troops from the point of view, also, of maintenance of discipline.[82]
The services rendered by railways in war relate much more to strategy than to tactics. Great masses of troops and munitions, brought from all parts of the interior, may be conveyed readily and safely by rail to particular points in the theatre of war; but the possibility of effecting their transport by rail from one point to another on the battle-field when the opposing forces are in actual contact is subject to many restrictions and constitutes a much more difficult undertaking.
The imperative need for guarding a long line of railway communications, more especially in occupied territory, may lead to the withdrawal of a considerable number of men from the main army, weakening the strength of the available fighting force proportionately.