Tunnels

feet, francs, tunnel, italy, axis, swiss, switzerland, miles, conditions and railway

Page: 1 2 3 4 5 6

Immediately following the opening of the °Mont Cenis' for travel in 1872, a work of much greater magnitude was undertaken not only to make another connection beween France and Italy, but to connect the North Sea ports with those of the Mediterranean; those of Bel gium, Holland and Germany,. with Genoa; and the Valley of the Rhine with that of the Po. The enterprise was too great for private indus try or capital, therefore, in 1871 Italy, Germany and Switzerland voted large subsidies for the construction of a railroad to run from Lucerne, Switzerland, to Lake Maggiore, Italy, a dis tance of 108 miles, 21 per cent or about 120,000 feet of which was to be tunnelled through mountains of granite. It was estimated that the work could be accomplished at a cost of 187,000,000 francs. An international treaty was signed; a stock company was organized with 34,000,000 francs of stock in 20 shares, and 68,000,000 francs of mortgage bonds. Italy gave 45,000,000 francs, and Germany and .Switzerland each 20,000,000 francs. This esti mate, however, was found to be too low by 102,000,000 francs, and caused a great many un necessary delays in the work, which was finally completed at a cost of 289.000,000 francs ($57, 800,000), of which $11,500,000 was expended on the Saint Gotthard tunnel alone, the location for which in spite of many undesirable topographical conditions was selected at the most central point of the Alpine range, on ac count of the directness of the route thus ob tained. The northern portal is situated near the little village of Goeschenen in the canton of Uri, Switzerland, from which the axis of the tunnel passes through the range under the lofty peak known as Col de Saint Gotthard, and emerges from its southern portal near Airolo in the canton of Tessin, Italy, after traversing a direct distance of nine and one quarter miles, and forms a part of the railway from Lucerne to Chiasso.

Unlike the case of its predecessor, the Mont Cenis, the tracing of its axis was beset by a great many difficulties, due to adverse topo graphical conditions. The axis of the Mont Cenis was traced under the mountains by means of three astronomical observatories, one being established at a high elevation and equipped with a telescope that revolved in the vertical plane passing through the axis of the tunnel. From this station the position of the other two observatories were determined toward the en trances, their telescopes placed in the same verti cal plane, and the direction of the axis supplied to them whenever necessary. The direction of the Saint Gotthard was determined by care ful triangulation; the fine topographic maps of Switzerland forming an important and valu able adjunct to the operations. Owing to the great elevation at which the tunnel was driven, that of the north and south portals being re spectively 3,639 feet, and 3,757 feet above sea— level, seven sets of helical or spiral tunnels, four on the Italian, between Giornico and Fiesso and three on the Swiss side, were constructed to bring the railway up to the great elevations of the portals. This system, designed by Hellwag, the engineer-in-chief, comprised a series of 100 tunnels in all, some of which are 6,000 feet or more in length, making the total dis tance tunneled slightly less than 23 miles. Un

der these conditions, the trains enter the foot of the mountains and by winding about through the spirals within its bowels, emerge along its sides a couple of hundred feet higher up at each lift until the entrance to the main tunnel is reached. The travelers are thus afforded suc cessive views of the magnificent Alpine scenery from various altitudes, passing within a few hundred yards of Rutli, Burglen, Altdorf and other spots made famous by William Tell, and ally. The force of laborers numbered 3,500 all Italians, while the officers were Swiss and Germans. The men were paid from three to six francs per day of eight hours' work, and had to board themselves. Under these cir cumstances the poor food with which they sup plied themselves contributed greatly toward the enormous death rate. Favre (Swiss) was the head of the firm of contractors. The cross sec tion dimensions of the boring is similar to that of the Mont Cenis, and is lined throughout with masonry 18 to 20 inches in thickness. It is equipped with a double-track railway, and re quired nine and one-half years of labor for its construction, which was commenced in 1872 and completed in 1882.

The third great Alpine tunnel, the ((Arlberg,' forms a part of the Austrian railway between Innsbruck and Bludenz in Tyrol, which con through the intricacies of the rugged Axen strasse. Salient facts relative to the construc tion of this tremendous piece of engineering may be briefly stated as follows: The work was prosecuted under the Belgian system, main heading; rock drills being operated and ven tilation accomplished by water power exclu sively. At the Swiss end, 1,220 horse power was derived from the Reuss. River by means of four horizontal impulse turbines, and at the Italian end, 1,220 horse power, from the com bined heads of the Tessin and Tremola rivers, by means of six turbines of the same type. These turbines working in pairs, drove groups of Colladon air compressors, which supplied 1,000 cubic yards of air per hour at a com pression of seven to eight atmospheres, equal to 100 horse power, delivered at the drills, which, when exhausted, equaled 8,000 cubic yards of fresh air per hour. Dynamite was exclusively used in the blasting operations, being considered cheaper and safer than nitro glycerine. At first the arrangements for venti lation were very inadequate, and combined with a lack of proper sanitary and hygienic regulations, resulted in a great loss of life. The application of the injector system of venti lation, invented by Signor Saccardo, engineer of Bologna, rectified these conditions materi nects westward with the Swiss railroads, and southward with those of Italy. It penetrates the Alpine watershed between the Rhine and the Danube, from Saint Anton to Langen, a distance of 10.25 kilometers, about six and one-third miles, its axis passing 1,594 feet under Arlberg Pass. The eastern and western portals are respec tively 4,277 feet and 3,985 feet above sea-level, with the summit at an elevation of 4,301 feet. Its construction was begun in 1880 and com pleted in 1883, at a cost of $7,500,000. Passen ger trains pass through the tunnel in about 25 minutes.

Page: 1 2 3 4 5 6