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TEXT A. PROGRESS IN TUNNEL CONSTRUCTION
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(1) Thousands of miles of railroad tracks in the world never see daylight for they are built in the black depth of the earth. It often takes great technical skill and ability to avoid tunnels because of their enormous cost of construction. But there are places where a tunnel is the only way through an obstacle. The Alps may serve as an example.
(2) For hundreds of years the peaks of these mountains had been an obstacle to communication between European countries. In the middle of the 19th century, constantly expanding railways made the French and Italian Governments seek for a direct connection. The experts spoke in favour of tunnelling. A tunnel eight miles through the Alps? Some people had doubts, but some dared to do it.
(3) Boring the Mont Cenis tunnel, the Alpine pioneer, was an extremely hard job. With only hand tools employed, the advance was very slow. Had the construction continued at the initial rate, it might have taken 75 years to complete the tunnel! However, with compressed-air drills and dynamite introduced, the progress was accelerated. In 1870 the news flashed through Europe that the Alps had been conquered at last. But the tunnellers may have encountered some more difficulties with the tunnel since it was only in 1871 that the Mont Cenis tunnel was opened fo'r traffic.
(4) The success of the Mont Cenis tunnel started a wave of Alpine tunnels, the St. Gotthard and Simplon tunnels being the most remarkable among them. The story of their construction is the story of constant struggle of tunnellers against the powerful,,foj;ces^of nature. Very often hidden mountain streams of extremely hot water rushed into the-workings. Rock dust and fumes from oil lamps and explosives filled the hot steamy air poisoning the workers. There is no need to say that a special ventilation system ought to have been used. Unfortunately, the ventilation methods being unknown at that time, the death-rate among the tunnellers was extremely great.
(5) In spite of all difficulties the workers and engineers completed their task successfully.
(6) Another tunnel of some interest up to our time is the tunnel under the river Thames. By present standards this tunnel may be said to be a very archaic structure, but it is still in use as part of the London underground railway system because it was a pioneer of construction in the modern manner. While building this tunnel Mark Brunnel, a celebrated engineer, worked out the idea of using a shield2 to lead the excavation.
(7) If you happened to travel by London Underground you must have read the following words on the wall of one of the stations: "This tunnel which runs under the Thames from this station was the first tunnel ever driven beneath the river. It was designed by Sir Mark Istambul Brunnel and completed in 1843."
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(8) Owing to В runnel's shield method and many other improvements in tunnel construction tunnelling has become a regular thing in railroad engineering.
(9) A significant progress has been made in tunnel boring in Japan. In this country the world's longest railway tunnel is to be built to link two Japan's islands Honshu and Hokkaido. Here are some figures to characterise this project. The total length of the tunnel is supposed to be nearly 54 km. At some points the tunnel is to be bored 240 m below the sea surface and 100 m above the sea bottom,
(10) You may have heard about the project of the Channel Tunnel which would permit to link London and Paris by a direct journey. This project has been much talked about for the last 150 years. The tunnel would have many points in its favour: it would not interfere with navigation, neither would it be affected by weather conditions.
(11) The long history of the Channel Tunnel began in 1802 when a French engineer Albert Mathiew prepared a scheme of a tunnel to link France and England. Had this tunnel been built the communication between these two countries could have been facilitated. But the plan had a short life for the war between England and France began in 1803, and the English people were glad that there was no direct link with France.
(12) In the course of time the existing means of communication between England and the continent could not cope with the increased volume of traffic. As a result, several projects of the Channel Tunnel were proposed. One of them was placed before the British and the French Governments in the 1950's.
(13) According to this project the Channel Tunnel was supposed to consist of a pair of single-track tunnels and a service tunnel, all being connected by transverse galleries at certain intervals.
(14) As fog, snow or ice could not interfere with traffic, a high degree of reliability would be attained. With electric traction being employed, the need for ventilation would be eliminated. The London to Paris trip would be made by through trains -in about 4 hrs 20 min. However, the project caused scepticism on account of its high cost, and the British Government refused from its construction because of financial difficulties.
(15) Nevertheless, the Channel Tunnel problem seems to be moving to its final solution for quite recently an agreement has been signed between the British and the French Governments giving the green light to a modified version of the Channel Tunnel rail project.
(16) The plan is reported to provide a high-speed twin rail link with shuttle trains3 cutting the journey time from London to Paris to three-and-a-half hours. When fully operational, the tunnel will carry over 4,000 vehicles an hour in each direction. The project is scheduled for completion in six years.
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