Discuss these questions with a partner.
1) What are the functions of ties?
2) What are ties called in the UK?
3) What materials are used for ties?
4) How can we make wooden ties last longer?
5) What are the advantages and disadvantages of concrete sleepers?
6) What are the functions of ballast?
7) What materials are used for ballast?
8) What is the best material for ballast?
9) Why must ballast be periodically cleaned or replaced with clean one?
10) What is a turnout?
Listening
Video 14
Study the words.
below – под
align [ə'laɪn] – выравнивать; alignment – выверка прямолинейности
crypt – углубление
grab – захватывать
Put the sentences in the correct order. Then watch the video and check your answers.
1) Align the new sleeper to its original position under the foot of the rail leaving enough space to insert new pads.
2) Clap the new sleeper from the trailer and insert the sleeper from the side again in two stages.
3) Dig out a crypt to a depth of around 2 to 5 cm below the sleeper base.
4) Fully pack the sleeper.
5) Grab the centre of the old sleeper with the help of the attachment and twist it on its axis to clear any loose ballast, then remove the sleeper in two stages.
6) It’s also advisable to mark the position of the chairs or base plates for the sleeper being removed with chalk or paint as this will assist in the alignment of the new sleeper.
7) Raise the new sleeper and align to the original markings and reclip the sleeper on the either side of the rail.
8) Scrape some ballast back into the crypt with the machine making sure not to hit the new sleeper with the attachment.
9) Scrape the remainder ballast back into the crypts with the attachment.
10) Then shovel up the new sleeper.
11) Then using the machine slide the sleeper forward and remove more ballast. This is done to allow the sleeper to be removed more easily.
12) Track gauge must be checked before the sleeper is removed.
13) Using the attachment clear the crypt to make way for the new sleeper.
14) Using the sleeper changing attachment slide the attachment between the ballast and the back of the sleeper and pull the ballast away from the sleeper to be changed, then repeat this step but this time for the crypt in front of the sleeper.
15) When the ballast is clear of the sleeper the operator can fully unclip the sleeper from the rail.
16) When the sleeper is halfway out, the attachment will need to be relocated on the other side of the rail to allow it to be fully removed.
17) When the sleeper is halfway, the attachment will need to be relocated on the centre of the sleeper on the other side of the rail to allow it to be aligned to its original marking.
Word list
| 1. | buckling ['bʌklɪŋ] | прогибание |
| 2. | crushed rock [krʌʃt] | щебень |
| 3. | dirt [dɜːt] | загрязнение |
| 4. | drainage ['dreɪnɪʤ] | дренаж, водоотвод |
| 5. | drawback ['drɔːbæk] | недостаток |
| 6. | flexibility [ˌfleksɪ'bɪlətɪ] | упругость |
| 7. | lateral ['lætərəl] | поперечный |
| 8. | longevity [lɔn'ʤevətɪ] | срок службы |
| 9. | rigid ['rɪʤɪd] rigidity [rɪ'ʤɪdətɪ] | жесткий жесткость |
| 10. | shell rock | ракушечник |
| 11. | strength [streŋθ] | прочность |
| 12. | turnout ['tɜːnaut] | стрелочный перевод |
Checklist
Assess your progress in this unit. Say what statements are true about you.
1) I know the meaning of the words from the word list.
2) My listening and reading are good enough to understand most of each text in this unit.
3) I can interview a person who works as a principal track engineer.
Unit 2 TRACK MAINTENANCE MACHINES
Start up
Discuss these questions.
1) Why does the track need to be maintained?
2) What are the functions of track maintenance machines?
Reading
Read the text quickly. Write the number of the paragraph (1-6) that gives you the information (a - f).
a) How tamping is performed
b) Stabilisation and consolidation
c) Functions of maintenance machines
d) From manual labour to mechanization
e) Levelling, lining and tamping must be performed
Text A
1 In the past, track maintenance tasks were carried out by manual labour, but today are performed using powerful machines.
2 Machines are available to do all the necessary track maintenancetasks: taking out and placing new rail, either in bolted lengths or with long welded lengths, pulling out old sleepers, putting in new sleepers, pulling or driving spikes, applying rail anchors, skeletonizing track, excavating and replacing worn ballast, tamping ballast, cleaning ballast, spreading and distributing new ballast, lining the track, grinding rails, cleaning the track from snow, etc. Some machines are equipped to perform more than one task – for example, ballast tamping combined with track lining and levelling.
3 Safe and comfortable travel in a train is only possible on tracks lying in the correct geometrical position. Levelling, lifting, lining and tamping machines make it possible to produce this state of the track. When a train travels over a track, it generates enormous forces. The entire track consisting of rails, sleepers and ballast is an elastic system that deforms and returns to its original position. Over the long period this high stress results in deterioration of the track geometry. To avoid such a situation, tracks should be maintained at regular intervals – this includes levelling, lifting, lining and tamping.
4 How is tamping performed? The tamping tines compact the ballast under the sleeper with a squeezing movement. The tamping tines vibrate and this directional vibration produces a homogeneously compacted ballast bed.
5 After laying a new track and following tamping work or ballast bed cleaning, some of the ballast stones are not in an ideal position to each other. This means that there is a lack of stability which is necessary to consolidate the track in the ballast ideally. The dynamic track stabilising machine has a vibrating unit which holds the track in position and applies vibration to simulate the passage of trains. This is transmitted to the ballast bed achieving re-arrangement of the ballast stones to produce a denser structure.