Railroad bridges and tunnels

GAUGE

CROSSTIES

RAILS

Ex.5.Read these short texts about the basic elements of the track. Retell them briefly in English.

Ex.4.Retell the TEXT according to the following plan.

Ex.3. Translate the following sentences into English.

1. Не смотря на возрастающую конкуренцию со стороны автомобильного, воздушного и морского транспорта, железные дороги были и остаются наиболее важным и универсальным транспортным средством для перевозки различных грузов и пассажиров.

2. Стальные рельсы высокого качества, деревянные или бетонные шпалы, щебеночно-гравийный балласт, все виды креплений – стыковые накладки, рельсовые подкладки, костыли, болты, – имеют большое значение для строительства прочного, безопасного, скоростного железнодорожного пути.

3. Длинные сварные рельсы обеспечивают бархатный путь для современных скоростных поездов и максимальный комфорт для пассажиров.

4. Уклоны и кривые влияют на скорость движения поездов и перевозимые грузы.

5. Железнодорожные мосты и тоннели проектируются и строятся через многочисленные водные препятствия и горные массивы.

6. Специальные инструменты и оборудование необходимы как для проектирования и строительства железнодорожного полотна, так и для эксплуатации и ремонта пути.

1. Basic elements of the track structure: a) rails; b) crossties; c) ballast.

2. Land for the rail track: a) roadbed; b) roadway and right-of-way; c) route.

3. The railroad gauge.

4. Grades and curves along the line.

5. Single-track and multiple-track lines.

6. Railroad bridges and tunnels.

Railroad rails are long heavy bars of steel of such shape that the cross-section of a rail looks like the letters “I” or “T”.

Rails are manufactured in great steel mills. A large ingot of white-hot steel is passed back and forth between the huge steel rolls that give the rails the proper shape.

After rolling is completed the rails are sawed to the standard length and branded. The brand shows the date of rolling, the kind of steel, the weight of the rail and the name of the manufacturer.

After branding the rails are cooled and straightened. Their ends are squared, and the holes are drilled for the bolts of the rail joints.

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Rails differ greatly in design and weight according to the kind of traffic they must support when placed in the track. The largest and the heaviest rails are to be found in the main line tracks that carry the largest volume of freight and passenger traffic.

Most of the rails now manufactured in Russia are 25 m long, and vary in weight from 60 to 75 kg to the meter. The most commonly used US rails are 39 ft long and range from 90 to 152 lb to the yard.

The crossties on which the rails are laid are nearly all of wood. Hard wood trees are the best woods for ties, because they are heavy and close-grained. Such ties last much longer but they are much more expensive than those produced of soft wood.

To make the ties made of soft wood last longer they are subjected to a protective treatment. The most common method of protecting ties is to treat them with creosote, forced into the wood under pressure.

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Ties cut from green timber must be seasoned before they are treated with protective materials and placed in the track.

The seasoning if done in the open air is called natural. It takes from 4 to 18 months depending upon the kind of lumber used and the local climate.

Scientists have developed a process by which ties can be artificially seasoned in a few hours. Under this method, ties are enclosed in a huge air-tight container filled with a chemically treated water vapor hot enough to draw the moisture from the wood but not hot enough to destroy the wood fibers. Although the process is rather expensive the saving in time more than offsets the cost.

A railway gauge is the width between the inside faces of running rails.

About 3/5 of the world’s tracks have the standard gauge of 4 ft 8.5 in. This gauge originated in 1829, when George Stephenson designed and built his famous Liverpool – Manchester Line.

The gauge was exported from Britain to Europe and the United States with the export of British locomotives built to it.

Among notable deviations are Russia’s 5-ft gauge, Spain’s 5-ft 6-in gauge, and Japan’s 3-ft 6-in gauge.

Several countries operate railroads on two different gauges; Pakistan operates on three; Australia and India use four.

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A uniform railroad gauge, regardless of its size, makes it possible for a person to travel over several railroads without changing cars.

When gauges were different it was necessary for freight and passengers to be transferred from one car to another at all points where there was a change of gauges.

The adoption of a uniform gauge has resulted in great savings of both time and expenses.

One of the oldest long railroad tunnels in America is the Hoosac Tunnel in Massachusetts opened in 1873. It is nearly 5 miles long and took many years to build. The longest railroad tunnel in the USA is the Great Northern Railway Cascade Tunnel in Washington, opened in 1929. It is almost 8 miles in length.

There are many long railroad tunnels in Europe, the longest being situated in Switzerland, France and Italy, beneath the snow-covered Alps and Apennines.

The St. Gothard Tunnel, the Simplon Tunnel and the Mont Cenis Tunnel are some of the best-known tunnels in the world.

Just as fascinating as mountain tunnels are the great bridges with the help of which railroads cross wide rivers or span deep valleys and canyons. Some bridges have a single high span crossing a river or a valley in a single jump. Most of the large railroad bridges are complicated steel and concrete structures.

Дата добавления: 2017-02-01