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ответить на вопросы по тексту. 100 ! the track is one of the basic features of a railway. it is also called the permanent way. the fact is that in the early days of railroad building the workers first had to lay temporary tracks to transport the materials to the construction site. and only after that they laid down the permanent tracks on the permanent way, as it was called. the permanent way consists of rails, ties and ballast. the railroad track of today is quite different from that used in the early days of railways. the first tracks had no ballast, the rails were made of wood and rested on heavy blocks of granite. then the wooden rails were replaced by iron ones, and the granite blocks were replaced by wooden ties. this kind of track, however, was not strong enough for heavy steam trains. the discovery how to make cheap steel was of great importance to the railways for, when placed in the same track, steel rails had a life 15 (fifteen) times as long as iron rails. the distance between the rails is called the gauge. the standard gauge in most countries is 1,435 ( one thousand four hundred thirty five ) mm while in russia the railroads have a gauge of 1,524 (one thousand five hundred twenty four) mm. that gauge was finally adopted when the first main - line moscow – st. petersburg railway was under construction (1842 one thousand eight hundred forty two - 1851 one thousand eight hundred fifty one). thus russia was the world's first country where the uniform gauge was adopted for all railways. in america the gauge was unified only in 1886 (one thousand eight hundred eighty six) . the place where the ends of the rails meet in the track is known as the rail joint. the rail joint has always been the weakest part of the track for nearly all the rails wear out first at the ends. some railroads have two or more tracks. in order to make the trains pass from one track to another the railroads have a switch which is a very important element of the track. the rails differ greatly in weight according to the kind of traffic which they are to carry when placed in the track. the largest and heaviest rails are laid in the main-line tracks for it is these tracks which carry the largest volume of traffic. the ties on most tracks were almost all of wood and in order to make them last longer they were treated with creosote. the ties are not laid upon the earth for the earth cannot support the track structure. they rest upon a bed of crushed rock, or gravel, which is called ballast. ballast supports the track structure, holds the track in position and provides needed drainage. the history of railways is more than one century and a half. during this period the track structure has been substantially improved. one of the greatest improvements was the elimination of rail joints. in order to reduce the number of joints the rails are welded into continuous lengths.these continuous or long welded rails have greater strength and provide a smoother running of trains at far greater speeds. another improvement which has made it possible to increase speeds on railways is the use of concrete sleepers. thus in some countries , concrete sleepers have replaced wooden ones on heavily used main lines because of their advantages. concrete sleepers have a longer life and a far greater weight than those made of wood. the greater weight of concrete sleepers provides the greater stability of track. it is this factor which has greatly contributed to increased speeds. how is the greater stability of track provided on modern railways ? why do concrete sleepers improve track stability?

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Ответ:
Dyba
Dyba
11.01.2023
1. The greater weight of concretesleepers provides the greater stability of track.
2. Concrete sleepers have a longer life a far greater weight than those made of wood.
4,8(55 оценок)
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Ответ:
marimitul
marimitul
11.01.2023

If you have even been inside the cockpit of a plane, you will have noticed the large number of instruments on the walls and ceiling around the pilot’s seat. Many of these buttons, dials and screens are used in navigation. Unlike car drivers, pilots do not have the luxury of signs and arrows telling them where to go. Instead, they rely on sophisticated GPS systems. So how were pilots able to find their way in the days before radio and satellite communication?

In the USA, the problem of navigation first arose when the airmail postal service was introduced in 1911. In the beginning, huge bonfires were lit to show pilots where to land in the dark. Later, a more practical solution was found: the construction of giant concrete arrows on the ground. The arrows were 21 m long and painted bright yellow. To enable pilots to see them at night, a steel tower with lights was built in the middle. The top light turned around to attract the pilot’s attention, and two others lit up the arrow and flashed a code to identify its location.

The first of these arrows was laid in 1924, and by 1929, there were around 1,500 of them. They formed an illuminated path for airmail pilots stretching from New York to San Francisco. The arrows were spaced about 16 km apart and were an important part of the Transcontinental Airway System. But by the 1940s, new navigation techniques were being discovered and soon, the arrows and their towers were no longer needed. They were gradually abandoned and some of them were removed completely.

However, not all of the arrows have disappeared. In the state of Montana, they are still used for guiding pilots through the mountains. Some are still visible in the empty areas of other states such as Utah, Wyoming and Indiana. Yet either because of their size or due to their bad condition, the arrows are not easy to find. In many cases, if you want to see one, it is a question of knowing where to look.

Which is where retired couple Brian and Charlotte Smith can help. The two are devoted fans of the arrows and spend much of their time hunting them down. So far, they have located more than a hundred of them. Once they find an arrow, they map its location, photograph it and upload the details onto their website. Their aim is to preserve the memory of these historical structures and prevent them from being lost forever.

4,8(81 оценок)
Ответ:
Zhannochka3110
Zhannochka3110
11.01.2023

16 Maria is the girl who mum drives us to school every day.

17 The car who Kanat bought is very fast.

18 The man which  suitcases were lost by the airline is very upset.

19 The pilot which is flying the plane is my uncle.

другие не хочу делать, я не знаю ну вроде правильно

Объяснение:

перевод

16 Мария-это девочка, которую мама каждый день возит нас в школу.

17 Машина, которую купил Канат, очень быстрая.

18 Человек, чемоданы которого были потеряны авиакомпанией, очень расстроен.

19 Пилот, который управляет самолетом, - мой дядя.

4,4(23 оценок)
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