The railroad track

(1) It is not an easy job to build a railway. The railway begins with laying a track on a strip of land called the right-of-way ¹. The track is, in fact, the basic feature of a railway. It is also called the permanent way – the term, which dates back to the early days of railroad building. At that time the workers first had to lay temporary tracks to transport materials to the construction site. And only after that they laid down the permanent tracks or the permanent way.

(2) Thetwo-century-long progress of railways changed not only locomotives and cars, but the track as well. The first tracks had no ballast; the rails were made of wood and rested on heavy blocks of granite. Then wooden rails were replaced by iron ones, and granite blocks were replaced by wooden sleepers or 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 steel rails had a life 15 times as long as iron rails.

(3) The permanent way of today consists of steel rails, fastened to cross-ties placed in a bed of gravel ballast. Now let us get acquainted with some important elements of railroad track more closely. Road-bed ²is the foundation for laying the ballast, ties and rails. Rails differ greatly in weight according to the kind of traffic and load they have to support. The largest and heaviest rails are laid in the main-line tracks, which carry the largest volume of traffic. Today, steel rails on lines with heavy traffic weigh as much as 60 or more kilograms to the metre.

(4) The distance between the rails is called the gauge. The standard gauge in most North American and European countries is 1.43m – the original gauge of the Stockton & Darlington Railway, adopted as а result of the export of English engineering and rolling stock. However, in Ukraine as well as in other CIS³ countries the gauge is broad (1.5m). That gauge was finally adopted when the first main line Moscow – St.Petersburg was under construction (1842-1851). Railways with the broad gauge also exist in a number of European countries, such as Spain and Finland. Differences in the gauge cannot but cause problems for international traffic crossing the borders. Recently a great number of projects have been studied to cut the time spent by trains at gauge changeover points⁴.

(5) Sleepers support rails and ballast supports sleepers. Sleepers on most tracks were almost all of wood treated with creosote for longer life. Now concrete⁵ is considered to be the ideal material for railway sleepers. Concrete sleepers have a far greater weight than wooden ones and thus provide greater stability of track and higher speeds.

Sleepers rest upon a bed of crushed rock or gravel, which is called ballast. Ballast is a very important element of the track for it is the ballast that supports the track structure, holds the track in position and provides the needed drainage.

Some railways have two or more tracks. In order to make trains pass from one track to another railways have a switch, which is a very important element of the track.

(6) Since the railroad beginning, the track structure has been substantially improved. One of the greatest improvements was the elimination of rail joints – the weakest part of the track. In order to reduce the number of joints rails are welded into continuous lengths⁶. Most main lines in Europe are constructed with continuous welded rail (CWR). CWR has greater strength, provides a smoother running of trains at far greater speeds and reduces maintenance costs. One of its noticeable effects – for passengers at least – is the elimination of the characteristic clickety-clack sound⁷ as the train crosses rail joints.

(7) Another recent improvement is the use of ballastless track for new high-speed and heavy freight lines. More and more countries replace traditional ballasted track with the so-called slab track ⁸. The principle is based on a completely new way of thinking in railway construction. Sleepers, fastenings and ballast bed are not needed because of the concrete slab superstructure with embedded rails⁹. The slab track has more advantages over ballasted track in terms of maintenance. Simple ballasted track needs continuous investment in track machines, equipment and manpower. Problems with ballast bed may occur where trains operate at speeds above 250km/h. Whereas balastless slab track has higher levels of safety, high precision, low life-cycle cost¹⁰, ease of replacement, and short installation time. Therefore slab track is justly considered to be the track for the future.

¹ the right-of-way – смуга відводу

² road-bed – земельне полотно

³ CIS – the Commonwealth of Independent States (СНД)

⁴ gauge changeover points – пункти заміни колісних пар

⁵ concrete – бетон

⁶ lengths – рейкові пліті

⁷ clickety-clack sound – стук коліс

⁸ slab track – безбаластна колія на збірних бетонних плитах

⁹ embedded rails – вмонтований, замурований

¹⁰ life-cycle cost – витрати під час періоду використання

Дата добавления: 2015-09-05