Yet while the distinction thus drawn between general railways and strategical railways is abundantly warranted, the increase of the former may still have an important bearing on the operation of the latter because of the improvement of transport facilities in the interior, and because of the greater amount of rolling stock which will be made available for war purposes. "From a military point of view," said von Moltke in the Prussian Herrenhaus on March 26, 1876, "every railway is welcome, and two are still more welcome than one"; and he developed this idea in a further speech on December 17, 1879, when, in declaring that the ownership and operation of the leading Prussian railways was desirable from a military standpoint, he said:--[52] Railways have become, in our time, one of the most essential instruments for the conduct of war. The transport of large bodies of troops to a given point is an extremely complicated and comprehensive piece of work, to which continuous attention must be paid. Every fresh railway junction makes a difference, while, although we may not want to make use of every railway line that has been constructed, we may still want to make use of the whole of the rolling stock that is available. Another important distinction between military and strategical railways is that whereas the building of the former will be governed primarily by military requirements, that of the latter may be fundamentally due to considerations of State policy. Strategical railways are wanted to serve the purposes of national defence or, alternatively, of national expansion. They are especially provided to ensure the speedy concentration of troops on the frontier, whether to resist invasion by a neighbouring country or to facilitate the invasion either of that country or, it may be, of territory on the other side thereof. The fact that they have been built may, in some cases, even further the interests of peace, should the increased means they offer for military transports render the country concerned a more formidable antagonist than it might otherwise be, and influence the policy of other States or lands accordingly. In tropical dependencies the building of railways as a practical proof of "effective occupation" is often regarded as preferable to military conquest, being likely, in most cases, to answer the same purpose while offering many other advantages, besides. In West Africa there are not only railways of this class but others that have, in addition, been designed as a precautionary measure against a not impossible invasion, at some future date, by Mohammedan tribes from North Central Africa. All such lines as these belong to the strategical type, though they may, also, serve an important part in furthering the economic development of the territories concerned.