Many schemes to connect Switzerland and Italy by a railway near the Simplon Pass had been in contemplation for several years. In 1881 the Jura-Simplon Railway advanced the scheme of piercing the Alpine barrier by a tun nel, which entering the base of Monte Leone at a short distance above Brigue, situated on the Switzerland side, on the left bank of the Rhone, and passing under the lofty mountain range, would emerge at Iselle on the Italian side, the distance to be traversed being somewhat over 12 miles. Since the days of the Roman Empire, the Simplon Pass has been the trade route be tween Milan and the flourishing cities of the Valley of the Rhone. For more than 2,300 years it was the great highway of trade and travel between southern and northwestern Europe. Over it, Hannibal led the conquering armies of Carthage., and, later, Czsar• his legions, when he laid the foundations of the Roman Empire. In modern times the Jura-Simplon Railway has run its trains along the same route, although laboring under the almost difficulties of excessive grades and the long distance com pelled by the ruggedness of the rock formation on the Swiss side of the frontier. The Swiss and Italian governments considered the scheme proposed by the Jura-Simplon Railway Com pany favorably and undertook its financing jointly. The Swiss government entrusted the work of construction to the Baugesellschaft fuer Simplon-tunnel, Brandt Brandau and Com pany extending to it a credit of $13,000,000, stipulating that the entire work should be com pleted in five and one-half years, the limiting date being stated as 21 May 1904. For each day that the work was finished prior to that date the company was to receive a premium of $1,000, and for each day of delay subsequent to that date it was to be fined a similar amount. The price named, however, was greatly ex ceeded, the actual cost finally amounting to $15, 700,000; the additional payment and the exten sion of time for completion being agreed to by the governments interested, on national grounds as well as in due recognition of the many un expected difficulties that confronted the con tractors and caused unavoidable delays. For example, although the advancement of the tun nel averaged between 500 and 700 feet per month, an advance of only 50 feet was made during the first three months of 1902, the work being retarded by the tapping of many springs and by the occurrence of numerous rock-slips.
The first blast in the work of boring was fired 21 Nov. 1898, the operations being carried on simultaneously at both the Swiss and Ital ian ends. In order to avoid the excessive freight rates compelled by the expensive opera tion of the traffic over the inclines of the Saint Gotthard, as well as for the purpose of making it an express route operating fast-train service, the altitude of the tunnel was kept as low as possible, although it might have been driven at a much higher level with an enormous saving in the cost. The Swiss end has an altitude of 2,250 feet and the Italian end 2,076 feet above sea-level, while the summit of the tunnel, where the ascending gradients from each end meet, has an altitude of 2,310 feet.
This funnel, unlike the other transalpine bor ings, which are single passages equipped with double tracks, consists of two parallel tubes or twin passages, each 161/2 feet wide, separated by a distance of 55.7 feet between their axes, each passage being equipped with a single track, thus permitting of travel in both directions at the same time. It is straight throughout its entire length with the exception of a short curve at each extremity, so that the new railway running from Brigue and gently ascending the valley of the Rhone for a distance of one and one-fourth miles, enters the tunnel on a right curve of 1,050 feet radius. The straight portion of the tunnel begins at a distance of about 460 feet from the entrance, extends a distance of 121/2 miles, at an obtuse angle with the Rhone Valley in Switzerland and the Val Vedro in Italy, and emerges on a left curve of 1,311 feet radius, above the banks of the Diveria River, on the Italian side. It has rising gradients of two per 1,000 from the Swiss side and seven per 1,000 from the Italian entrance, the summit of the tunnel or the meeting point of the gradients being at a distance of 5.944 miles from Brigue, at an altitude of about 2,310 feet above the level of the sea, and about 7,000 feet below the crest of the mountain between the Furggen baumhorn and the Wasenhorn. The two pas sages are connected by transverse galleries or cross-headings at intervals of 660 feet, thus facilitating ventilation and problems of trans portation. At the summit the transverse gal lery is excavated to double width and affords room for the central station located at that point.
The working force numbered 1,000 men, di vided into three shifts on the eight-hour basis, so that the work was carried on continuously day and night during the entire period of over six years. These laborers were all Italians, the Swiss having no adaptability to the work of blasting rocks and removing debris, thousands of feet below the snow-capped mountain ranges or the verdant hills upon which they tended their herds and crops. This small army of workmen was comfortably located in well arranged quarters which were erected across the river near the Swiss portal, and every neces sary precaution was taken to protect their health and keep them in a fitting condition to prose cute their labors. The many fatalities conse quent to a lack of these precautions in the con struction of the Saint Gotthard afforded an example by which the Simplon management profited greatly. At the Swiss end they estab lished a fine hospital with facilities for treating emergency and contagious cases. Sanitary and hygienic regulations were strictly enforced. When a shift of laborers was relieved and came out of the hot workings in the tunnel, each man was required to take a bath at once, before being exposed to the keen Alpine atmo sphere, and he was required to hang his damp working clothes in a drying room, and put on another suit while he was off work. As the Simplon boring was executed at a depth rang ing from 5,000 to 7,000 feet below the surface of the mountains, about 50 per cent deeper than had ever been required previously, the en gineers were compelled to devise means to ameliorate the resulting conditions of torridity, in which the temperature frequently rose to 110° F. These conditions were modified by pumping cold water from the outside into the boring through pipes pierced with small holes, so that the water fell upon the laborers like a fine rain or drizzle, and through this liquid veil the fresh air was forced and cooled to a bearable tem perature. The general refrigeration was ef fected by means of 34,118 feet of 9.96 inch piping from each end, connected to four re frigerating appliances of 71 heads and 11 jet sprays placed at intervals along the boring, so that the spray would bathe all the sides of the headings in the neighborhood of rock heated to a temperature by infiltration from hot springs, the waters of which were of a parboil ing temperature and often exceeded 112° F. The plan of carrying away the hot water to some point where its effect would not cause the same local inconvenience was uniformly pursued, but only partially prevented the heat ing of the air, although the greatest care was taken to insulate the pipes both from hot and cold radiations. Ventilation was accomplished with the aid of the auxiliary tunnel, No. 1. It is to be understood that of the twin passages, the one designated as No. 2 was completed first, that is, enlarged from the heading to its ulti mate dimensions, passage No. 1, at first being carried on with much smaller dimensions, and forming an important adjunct in the system of ventilation. The compressed air for this pur pose and for operating the compressed air loco motives was carried through tunnel No. 1, to the headings through pipes varying from 1.18 to 1.97 inches in diameter; air valves on the main at various points enabling the recharging of the locomotives. When the heading face was some distance in advance of one of the transverse gal leries cool air was supplied to a nearby point through a light sheet-iron pipe carried imme diately below the roof of the heading. At inter vals a connection was formed between the hy draulic pressure main running along the floor of the heading, so that a jet of air was forced into the overhead pipe under a pressure of about 78 atmospheres, inducing a strong current in the pipe which was conducted right up to the face. The water was collected in and drained off a number of siphons placed at intervals along the air main. During the last two years of the work compressed air locomotives were exclusively used at the Swiss end as the use of horses for switching the spoil trucks at the headings was made impossible by the heat of the tunnel. An important feature of the entire work was the fact that no possible advantage that could be derived from transported hy draulic force was neglected. The water dis charged from the tunnel from tapped hot springs and infiltrations amounting to 50 or 60 gallons per second was utilized to operate the ventilator turbines, as also the return water pumped into the tunnel for power to drive the rotary drills and for purposes of refrigeration.