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Permanent Way and Its Members

A permanent way is a structure, consisting of track and ballast. The track is one of the principal structural element of a railway, including rails, sleepers (crossties, ties) and rail joints for connecting rails and their fastening to sleepers. It is also called the permanent way.

The principal function of the permanent way is accepting the imposed dynamic and static loads as cars, locomotives and trains travel over the track.

All elements of the permanent way must be strong and durable in railway operation in order to ensure the safety of travel. The maintenance of the permanent way must be cheap and besides it must have a long service life.

The railway construction with all its problems of track construction, ballasting jobs and so forth, is primarily an engineering problem. Permanent way is the important structure which interacts with the rolling stock providing railway traffic.

The railway track of today is quite different from that used in the early days of railways. The first track had no ballast, the rails were made of wood and rested on heavy blocks of granite. But in general and fundamental concepts the modern railway track is not greatly different from that of a hundred or more years ago. As then, it consists of two parallel rails, supported on and fastened to a serious of sleepers which are laid on a suitable material known as ballast. It's the foundation of the railway which holds the track in line and provides needed drainage.

The rails differ greatly in weight according to the kind of traffic, which they have to carry. The largest and heaviest rails are laid in the main-line tracks for it is those tracks which carry the largest volume of traffic.

The history of railways is more than one century and half. During this period the permanent way has been substantially improved. In order to reduce the number of joints the rails are welded into continuous length. This continuous or long-welded rails have greater strength and provide a smoother running of trains as far greater speed.

Recently the crossties consisted almost universally of wood treated with creosote to protect it against decay. Now the rails are supported on concrete ties, prestressed concrete ties or steel ties in all main line tracks.

They 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's this factor, which has greatly contributed to increase speeds. That's why the weight of rails and length of track on reinforced-concrete sleepers are increased with every passing year in our country.

At present the permanent way is characterized of the design variety of switches, types of rails, rail fastenings. Particular consideration is given to the increasing reliability of switch elements. New types of switches have been developed on reinforced concrete bars. It has been improved on the position of switch structure and increased service life of reinforced concrete bars in comparison with the wooden ones. Switch on reinforced concrete bars became the base for similar switches of new generation. They are produced for passenger train movement with the speed up to 200 km/h.

Last years the universal track-laying by switch blocks on reinforced concrete bars is carried out. The technology of switch assembling is used in two ways: directly at the laying site or at special bases with the further delivering to the laying site on special platforms. Here track-laying switch cranes are employed.

All these improvements have become necessary, because of constant and progressive increase in train loads and speeds the need for providing a permanent way. Only the strong track can ensure safe and uninterrupted traffic.