Though these sections of the railway had proved difficult to carry out, it was the Tauern link in the chain that tried the energy and ingenuity of the engineers to the supreme degree, for on this stretch of railway the mighty Tauern group of mountains had to be negotiated. Surveys showed that to pierce this clump involved the boring of a tunnel for a distance of five miles at least. They proved the hardest five miles in the whole undertaking; the piercing of the Karawanken and Wochenier tunnels sank into insignificance by comparison, for this knot of the Alps was found to be formed of much sterner rock. Granite gneiss, one of the hardest substances against which it is possible to bring the edge of a drill, made progress provokingly slow. At times, when the hand drills had to be used, an advance of two feet in the course of twenty-four hours was considered excellent. The Brandt hydraulic drills, however, with the enormous energy behind them, made the task somewhat lighter, for they moved through the hardest rock at a rate of about seventeen feet every day, with occasional spurts of a foot per hour.
In this undertaking, however, many misfortunes served to delay progress. The task had barely commenced, when a flood destroyed part of the works at the northern end. The river whose water had been harnessed had been deviated from its accustomed path, because it flowed over the roof of the tunnel. As the engineers had no desire to invite an inundation by tapping the bed of the river waterway, they had provided it with a new channel. Heavy snows and rains, however, so swelled the volume of the diverted river that it broke through its artificial bonds to resume its original course. The result was that, owing to the crust of earth between the old bed and the roof of the tunnel being so thin, the water crashed through, and poured into the tunnel in an immense cascade.
The men abandoned everything hurriedly, and rushed madly for their lives from the incoming avalanche of water. For days the tunnel was absolutely inaccessible. Not content with flooding the workings, the impetuous torrent completed its devastation by sweeping away many of the supports to the line conveying the water to the drills under a pressure of 1,500 pounds per square inch, leaving the slender conduit of this great force hanging in graceful festoons in mid-air. Some of these gaps were as much as 260 feet in width, and had a break in the pipe occurred widespread damage would have been caused. But the engineers set to work, and reconstructed the temporary dam that had thus been torn roughly away and rebuilt the river’s new channel. At the same time they adopted such precautions as would preclude the possibility of the waterway again inundating the tunnel in times of the most severe floods.
Such incidents, however, are inherent to works of this character. The inundation was but one means adopted by Nature to thwart the advance of the iron road. Work had scarcely been resumed, when another disaster occurred. The drills were whirring merrily against the rock face in the tunnel, and the drillers were light-heartedly conversing with one another as they fed the boring giant in its rock-penetrating task. Suddenly there was a cry of alarm. Water was trickling rapidly from a bore-hole; it rapidly increased in volume. The drillers hurriedly withdrew their tools and backed down the cavern. There was a roar, and a limpid stream burst from the rock face. The drillers stampeded; they had tapped a subterranean spring, and it was now rushing forth with fiendish violence. The engineers hastened to the front. Such a contingency had been expected, for such incidents are inseparable from tunnelling tasks of this magnitude. The rushing stream was turned into one of the conduits at the side to carry it to the tunnel mouth, where it expended its energy harmlessly by tumbling wildly among the rocks. When pockets of water and springs are tapped in this manner, the question is to control the water so encountered in such a manner that it does not interfere with the drilling work or flood the workings. As a matter of fact, when the Simplon tunnel was in progress these underground springs were harnessed and compelled to perform useful work; they were thrown against the rock face to keep down the internal temperature.
Work continued incessantly day and night; but it was hard and exhausting the farther the men advanced. The drills scarcely could bite into the rock, as it was so tough. At one time the question became so acute that the engineers brought up the electric drills used in the Karawanken undertaking in order to see if matters could not be expedited, but they failed to make as much headway as the hydraulic tools. Another handicapping factor was the heat, which rose very rapidly, and although it did not attain that degree experienced in the boring of the Simplon, yet it caused considerable fatigue among the workmen engaged in such a confined space. The elaborate ventilating system sufficed to keep the air as sweet and cool as possible, but it did not solve the problem completely. The workmen, cramped as they were in the confined space—the area available for manipulating the tools only measured a few feet in each direction—often betrayed painful signs of physical distress.
But at last there was a wild cheer, which echoed and re-echoed through the caverns to the tunnel’s mouths. Those outside realised that something untoward had occurred, and in a few seconds the news came through the gloomy depths that the drills had pierced the last 72 inches of rock separating the two headings, and that the Tauern was conquered. That was on July 21, 1907, some five years after the first boulder was torn from the mountain-side. Once this last barrier was broken down the finishing touches were soon applied, and the double track laid from end to end.
Though the Tauern tunnel constitutes the outstanding features on the section stretching from Schwarzach St. Veit to Villach, there are innumerable other subsidiary works which in themselves are of importance. One of more than passing interest is a clever piece of construction in order to overcome a difference of 2,975 feet in level between the Tauern tunnel and Ober Villach by means of a huge “S” loop four and a half miles in length.
The fulfilment of this undertaking constitutes one of the most remarkable railway engineering feats in Europe. Certainly it ranks among the most expensive enterprises that ever have been attempted west of the Urals. To the travelling and commercial community its value is incalculable, for Munich, which was formerly a tedious journey of twenty-three hours from Trieste, is now within twelve hours’ run, while the other great centres of Europe have been brought proportionately nearer the Adriatic by this new and more direct route.