Crossties, ballast and turnouts — КиберПедия 

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Crossties, ballast and turnouts

2017-05-22 270
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Railroad ties, also known as crossties or sleepers are the lateral support for the rails. The wooden tie is treated with creosote to improve its life. Wooden ties provide sufficient strength and are relatively inexpensive compared to concrete ties. Railroads employ concrete ties on heavily used main lines. The one drawback of concrete is that because of its rigid qualities it does not have the same flexibility as wood. However, thanks to its strengths and longevity over wood, in the future you will almost surely see more and more main lines employing concrete ties.

Ballast is used to distribute the load from the ties, to prevent the track from buckling and to provide drainage. Ballast also acts as a support base for the railroad track giving it strength and rigidity but also allowing for flexibility when trains pass over. Ballast must regularly be cleaned or added as dirt reduces ability of ballast to properly drain water. Crushed rock is the best material for ballast; however, gravel, sand, asbestos, and shell rock are also used.

A turnout, also known as a point and a switch, is used to guide trains from one track to another. It typically consists of a frog, check rails and two switch rails. The switch rails may be moved left or right, under the control of the signaling system, to determine which track the train will follow.

 

Vocabulary

Match the term with its definition.

 

1) ballast a) the distance between the inner faces of the rail heads
2) nut b) a metal part with a hole whose surface is threaded for screwing onto the corresponding bolt
3) rail c) the means of directing a train from one track to another
4) tie / sleeper   d) a piece of wood or concrete that is set in ballast and supports the rails to distribute the train’s load and keep the rails parallel
5) joint bar / fishplate e) a steel fixture on a sleeper which secures the rail in the correct position
6) spike f) the place where ends of rails meet in the track
7) turnout g) a steel bar that is attached to sleepers; the train’s wheels roll along it
8) gauge h) the trackbed upon which ties are laid
9) tie plate / chair i) a steel plate that is fitted to the two sides of the rail webs to join them end to end
10) joint j) a large nail with an offset head that fastens the foot of the rail to the wooden sleeper

Comprehension

Exercise 1. Decide if the sentences are true or false.

1) Good quality ballast is made of crushed stone.

2) Wooden ties have longer life than concrete ones.

3) Concrete is more flexible than wood.

4) Drainage is keeping water away from the track.

5) The switch rails are the moving part of the turnout.

 

Exercise 2. Complete the table. Choose from the list.

Functions of the track

Rails Fittings Ties Ballast Turnout
         

 

1) to provide level and hard bed for sleepers

2) to hold rails to correct gauge

3) to provide continuous and leveled surface of the track

4) to fix rails with sleepers

5) to provide longitudinal and lateral stability to the track

6) to provide drainage

7) to provide guidance to wheels

8) to enable the movement of trains from one track to another track

9) to transfer and distribute load from ties to wide area

10) to fasten rail to rail

11) to keep down vegetation that might interfere with the track structure

12) to transfer load to ballast

13) to hold ties in position

14) to provide firm and even support for rails

15) to provide elasticity for track

Exercise 3. Complete the table. Choose from the list.

Sleepers
Wooden Concrete Steel
Advantages Disadvantages Advantages Disadvantages Advantages Disadvantages
           

 

1) Stability to track (due to greater weight).

2) Handling and laying is difficult (due to greater weight).

3) Easy to manufacture and handle.

4) Long service life.

5) Short service life.

6) Track circuiting is possible.

7) Unsuitable for track circuiting.

8) Liable to corrosion.

9) Damage due to pests and decay is possible.

10) Free from fire hazard.

11) Susceptible to fire hazard.

12) Lesser damage during handling / transportation.

13) Correction to alignment is easy.

14) Heavy damage during derailment.

15) Good scrap value.

16) Maintain gauge and alignment better.

17) Cheap.

18) High rigidity.

19) Provide smoother running of trains.

20) Lower maintenance costs.

 

Speaking


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