RAILWAY BETWEEN DOVER AND CALAIS.

Star (Christchurch), Issue 350, 28 June 1869, Page 3

RAILWAY BETWEEN DOVER AND CALAIS.

For some years past there has been a considerable amount of attention directed to the probability of effecting a communication between England and France Avithout the necessity of undergoing what to so many persons is regarded with feelings of aversion — the short sea passage. The idea of making a tunnel under the Straits of Dover was suggested to Napoleon the First, but then the scheme merely contemplated a carriage way and footpaths on each side of the road. In 1857 M.de Gamond prepared, with great elaboration, his plans for a tunnel, sous mar in, between England and France, showing the position and dimensions of the various shafts and plans of a central dock, to be constructed in the Straits. Mr Remington, an English engineer, also prepared plans on the same subject, and Mr Hawkshaw, the engineer, has for some time past been engaged in taking preliminary soundings and surveys for a tunnel. A distinguished French engineer, desirous to avoid the making of a tunnel, boldly suggests the construction of a bridge across the Channel. To this list of projects may now be added one which shows that in the matter of crossing the Channel more than the usual three courses wliich are applicable to every matter are available. The Channel, for instance, may be crossed above by means of a bridge, upon it by steamer, and beneath by a tunnel. A fourth mode proposed is that of going neither above, upon, or below, but through the body of the water in the Straits. It is actually proposed to build a tube, sink it partially, and support it in the water in such a manner as to admit of the passage through it of trains, or a double line of railway. A more daring engineering scheme was probably never suggested. It is proposed tbat the iron tube for the railway shall be laid across from the English to the French coast, and be supported at a depth of about 50 feet below the surface of the water by iron stanchions or tressels, the feet of which will rest upon the bed of the straits. The tube is to be in its outside diameter 23 feet 6 inches, and with a view of giving it sufficient strength to resist the pressure of tho weight of the water ; to sustain the weight of the trains between the points of support; and to allow for the decay caused by the action of the water, the tube is to be of cast-iron, 8 inches in thickness, being nearly twice tbe thickness of the armour-plates of the Warrior ironclad. The length of the tube between each pair of legs or supports is to be 300 feet, and the weight of each of these sections 3000 tons. Each of these lengths of 300 feet is to he made up of eight segments of 37 feet 6 inches, and these are to be firmly bolted together by means of 100 steel bolts passing through the internal flanges of each length of tube. Ask the bold engineer how these segments arc to be put together in the water, and he explains the matter in the most practical manner. Each segment will be made watertight, by a bulkhead, and will be lowered until it is brought into exact position with the portion previously fixed, and when made fast by the bolts the near bulkhead will be removed, and the workmen will pass on to the next section. The stanchions which will have to carry the tube are made, as it may be supposed, of enormous strength. They will vary in length according to the depth of the wafer. The largest will be 106 feet in length; it will be formed hollow, tapering from each and to the. middle, when it will be; "7 feet V 2 inches ..in, diameter, the^nds being; s : feet_B inchea'infliajn^DSii- Th§y be.castVin ihree'jiietjes, and bolted together by cwt ' steel Volts on '

inside flanges'. The weight of each of these legs or stanchions will be 454 tons. In order to give them a sure foothold afc the bottom of the sea, they will be fastened by bolts to discs of metal 25 feet in diameter, and weighing 85 tons. To prevent any lateral motion, the feet of these stanchions will be held together by tension bars 100 feet long, and weighing 60 tons, and a similar tension bar, though of less length, will connect and hold the stanchions at the upper extremity. The bolts that are to hold and keep the stanchions apart weigh not less than 4£ tons each. The transverse strength of the tube when completed has been satisfactorily ascertained to be 27,034 tons, and if loaded in the middle it would safely carry 2300 tons weight. In order to sink the tube, each section of 300 feet will be loaded with 433 tons of rails, air. and water tubes, and of 1800 tons of ballast or shingle, each segment as it is lowered being provided with its due share of dead weight, to ensure the necessary displacement of water. The pressure of the flow of the tides will be equal to 4501bs on every square foot of the •ross sectional area, but the stanchions are calculated to be of sufficient strength to resist any movement from 'this cause. The ventilation of the tube is to be provided by " stationary steam power at one of the entrances to the tube, which will force a sufficiency of air through a channel constructed along the inner roof of the tube to a point about midway of its entire length, where it will be discharged and force itself along the tube to either end, providing at the same time a perfect system of ventilation. The draining of the tube is duly provided for; the water will be collected in the lower part of the tube, and as the locomotives pass through they will take up the water in a trough, in the same manner as the engines are supplied on the London|and North-Western Railway while travelling. The casting of the various portions of the work is to -be done in a dock to be formed on the coast, and the various portions, as they are cast, are to be floated by letting in water, and takeu out to sea by pontoons, to which they will be attached by suitable chains. The cost of this extraordinary work is set down at from ten to fifteen millions; the designer of the plans being Mr Purkis, the engineer.