THE CHANNEL RAILWAY.

Globe, Volume V, Issue 567, 12 April 1876, Page 3

THE CHANNEL RAILWAY.

(Times, Jan. 20.) The scheme for a submarine railway under '••the Straits of Dover, which was revived •about two years ago, af tor it had lain in abeyance for some time, is rapidly taking shape and consistency. An Act of Parliament was passed last session empowering a company to -acquire lauds for the purposes of preliminary 3 investigations on the English side of the '-Channel, and, at the same time, the French /Assembly gave corresponding powers to a 'French company. The time allowed for •commencing these preliminary operations is •only twelve months, so that we shall probably shortly witness a resolute attempt to explore ■the bed of the channel by actual excavation. In a Blue Book which has just been published, containing the discussions and correspondence on the subject, there will be rfound, among the documents submitted by ithe French Government to the Engl.sh 'Cabinet, a very complete and able exposition of the prospects and conditions of the enterprise, so far as they can at present be determined. The members of the French Commission, to whom the project was referred, do not ignore the difficulties and hazards inherent in the scheme ; but they unanimously recommend that the experiment should be made, and that the sanction of the Government, though without subvention or guarantee of interest, should be accorded to it. The attitude assumed by our own Government towards the English .Channel Tunnel Company is substantially -Similar, and the legislation of last year in both oountries gives practical effect to the recommendations of the French Commission. ...... ~ i i It is proposed that the actual submarine tunnel should start from St, Margaret's Bay, a little to the east of Dover, and should teach France at a point somewhat to the West of Calais, between that town and the Village of Sangatte ; and it is at these two bOtnts that the preliminary excavations Which have beer, authorised will be made The longitudinal section of the tunnel would take the form of an arch of almost imnerceptible curvature; the drainage being thus conveyed to each end by gravitation, and carried through properly constructed culverts to wells at convenient inland points, from which it would be pumped to the surface; On quitting the bed of the sea the tunnel itself would rise by an easy gradient to the surface at some distance from the coast; and the ordinary junctions might be effected with existing lines of railway on either side. Such is a rough outline of the proposed scheme, and certainly on paper it loots feasible enough, but it would be idle to overlook the enormous difficulties of every kind-Bnancial, engineering,. mechanicai, political, and even strategetical -which will have to be surmounted. . It is, however, almost inevitable that such an experiment should, sooner or lat 3 r, be seriously made . •"Impossible" is a word long ago erased from the engineering dictionary. The Suez Canal is one accomplished impossibility ; the

Mont Ceniß Tunnel is another ; and the success of the St Gothard Tunnel, ii» some respects a still more formidable enterprise, is already practically assured. But to construct a submarine tunnel of over thirty miles in length is an enterprise of very exceptional difficulty. Even if it were made to-morrow, is it certain that ordinary travellers would use it ? The experience of the Alpine tunnel would, at first sight, seem to give a triumphant answer to this question. But a tunnel seven miles in length is a very different thing from one nearly five times as long, where a breakdown in the middle would leave the travellers over 15 miles from succour and assistance. This, however, is a d-ffieulty which cau only be solved ambitlando. If the promoters are content to take the risk the public will certainly use the tunnel as soon as its security and convenience have been demonstrated. The really hazardous aad incalculable element in the scheme is the geological structure of the material through which the tunnel will have to pass. The external geological aspect of the coasts which face each other across the Straits of Dover is similar enough. We all know the chalk cliffs which meet us on either side of the Channel, and so far as soundings can give us information, it seems that the bed of the sea between the two points is composed of the same white chalk. This white chalk however, although it probably extends to a considerable depth, is known to be so porous and full of fissures, that " it would be dangerous to rely on it, and it seems impossible to eliminate the chance of a sudden irruption and collapse. Fortunately, below the white chalk there is found a thick layer of gray chalk of a far more uniform consistency, and this is said to be easy to work, and without serious risk. This gray chalk exists on both sides of the Channel in the same relative position, and there is fair reason to hope that it is also continuous throughout the bed of the Straits. On the existence of this continuous layer of gray chalk the whole success of the Channel Tunnel depends. Engineers and geologis's are sanguine on the point, but at best their opinion rests on conjecture, and can only be verified by actual experiment. Should the white chalk make a sudden dip the excavation will be fruitless ; should harder rocks make their appearance, the cost of piercing them may swallow up all prospect of profit Indeed the general financial aspect of the scheme is far from encouraging. On this point thecommentofthe Board of Trade is frank, not to say brusque :—" As to the prospect of obtaining any income from the traffic sufficient to pay interest on the outlay, they cannot, looking to the large sum required, and to the competition by sea (which must always exist in respect of merchandise, if not of passengers), take a very sanguine view. This, however, so long as the Goverment is not asked for money, is a matter for the promoters rather than for them." The horror of eea-sickness, with the other discomforts of the Channel passage, is the chief motive on which the promoters must rely for a profit; will it suffice to pay a remunerative dividend on such an enormous outlay ? Of course, the transport of merchandise will contribute its share ; but it is precisely on this point that it is impossible to guard against ruinous competition. It should be recollected that here the experience of the Alpine Tunnels is of no avail, for they open entirely new and abridged channels of communication, and there is no competition to speak of. No doubt the political and international difficulties of jurisdiction and control can be surmounted by negotiation and mutual arrangement ; but we look in vain in the Blue Book for anything approaching an adequate discussion of the great strategical difficulties inherent in the scheme. It is true that each Government announces its intention of reserving its entire freedom of action as to the measures it may think fit to take for protecting the entrance to the tunnel, and, as is somewhat significantly added, for rendering it useless in time of war. No doubt proper defensive work 3 would suffice to guard against a coup de mam by means of the tunnel itself ; but, if these were takea in rear, as they might be as regards England, by a successful iavasion on the East Coast, what becomes of England's command of the sea ? This is a remote contingency, it will be Baid; but all our defensive measures have reference to similar remote contingencies, and we cannot afford to leave to a possible enemy an unassailable line of land communications with his base. We cannot but think that England's defensive security absolutely requires that, if the tunnel is made there must be provided means of rendering it swiftly, and, for the time, irreparably useless, as, for instance, Hooding its entire length in case of need. The constructors of such works hold the position of those who build house within range of a fortress; they take their own risk, and tbey know beforehand that they must yield to the imperious necessities of warfare. Yet these indispensable strategical conditions must of necessity react upon the financial difficulties of the scheme. The company will have to take the risk of complete and indefinite suspension of traffic, and to bear the expense of the very costly removal or the obstruction agreed upon, of whatever nature it may be. Still, as these difficulties have been got over, in the somewhat analogous case of the two alpine tunnels, we suppose they are capable of solution. After all, the real difficulties of the scheme reduce themselves to two, wMch may be very simply stated —Is it feasible, and will it pay ? The first question can only be answered by experiment, and the second, at best, by more or less plausible conjecture; but those who have given most attention to the Bubject have provisionally answered them both by a not very hesitating affirmative.

We by no means desire to discourage a scheme which is, at least, a credit to the enterprise of those who have promoted it. The names of M. Michel Chevalier and Sir John Hawkshaw are a sufficient guarantee that their fellow-countrymen who are associated with them in this scheme are anything but visionaries and enthusiasts, and when practical men of great experience and ability are ready to engage in so gigantic an enterprise, they deserve our warmest sympathy. But we must not for all that shut our eyes to difficulties and obstacles; the questions we have raised are suggested aim st entirely by the discussions reported in the Blue Book, and even those who have most strongly recommended the project have only ventured to oSer a hesitating and tentative solution. We shall await with •jreat interest the result of the preliminary excavations, for it is admitted that on the materials they offer for a solution of the geo'ogical problem the whole success of the enterprise must depend. The financial que3 tion will have to be resumed and fully du cussed when the final and definite project is

before us. Meanwhile, it is satisfactory to observe that the French Government are by no means disposed to let the Channel Tunnel project divert their attention from the more immediately practical question of improving the existing means of maritime communication between the two countries. They prefer a tunnel to the rival proposals of a railway ferry, a lofty bridge, or a submarine tube, and probably they do so for very good reaions; but they admit that there is room for improvement in the harbours of Calais and Boulogne, and that such improvement is of immediate and pressing importance. It ie not on this side of the Channel that the chief obstacles to a fairly comfortable passage exist, for vessels of almost any tonnage can moor alongside the Admiralty Pier at Dover. We do not hear complaints of the longer and more stormy passage between Holyhead and Kingston, such as are constantly reaching us in regard to the dread "middle passage" of the Straits of Dover. The reason is simply that in the former case the harbors are large and the boats commodious, while in the latter, even if we build large and comfortable boats, they cannot get into the French harbors. The experiments with the Bessemer and the Castab'a show that there is no lack of enterprise on our side, and the latter, at any rate, is—at least, in principle—a success, notwithstanding the rather ill-natured competition she has had to contend against. If the Channe' passage could be effected in comfortable and roomy steamers, in .which a reasonable regard was paid to the ordinary wants of human boiugs at sea, the transhipment might be rendered only a little more irksome to passengers than a change of trains on land is generally felt to be. The Fieuch Government announces its intention of pushing forward adequate measures for remedying its share of the existing evil. If this is effectually done, men's views as to the necessity and convenience of a Channel tunnel will perhaps undergo a change. At all events, without waiting for the issue of j so costly and hazardous an experiment, it is as well iu thi meantime to exhaust the ordinary and well-known means of removing an acknowledged, and, among the miuor ills of life, an almost intolerable evil.