It is important that the exact quantities of track material are conveyed to the site. Any excess material gets wasted, whereas shortage of material results in difficulties and delays in carrying out renewal work. It is normally desirable to have a small spare stock of extra material ready in case of unforeseen contingencies.
The exact quantity of material required for 1 km of track is calculated as given below.
If the track is an ST sleeper track with 52-kg rails and sleeper density M + 7 (where M is the length of the rail in metres, which is normally 13 m on BG), then the calculations are as follows.
Fish bolts Each joint requires four fish bolts:
Number of fish bolts = 4 x number of rails per km = 4 x 154 = 516
Fish plates Each joint requires two fish plates:
Number of fish plates = 2 x number of rails per km = 2 x 154 = 308
Keys Four keys are required per sleeper:
Number of keys = 4 x 1540 = 5160
Loose jaws Four loose jaws are required per sleeper:
Number of loose jaws = 1540 x 4 = 5160
Track renewals are required every year to keep the track safe and in good running condition. The tracks on Indian Railways require heavy renewal since they are very old and have been in use for a very long time. Track renewal is done to rectify defects in rails, fish plates, and sleepers. The track renewal train is used on Indian Railways for mechanized renewal of the track. It can lay 16 sleepers per minute and is able to give an average output of 200-250 km/year.
1. Categorize the different types of rail wear and enumerate the steps to reduce the same.
2. Discuss the standard method of re-laying a track. Also discuss the various aspects to be kept in mind when replacing a track.
3. What is meant by spot and through renewal of track components? Discuss the reasons for the same along with the methods employed.
4. Why is re-laying of a track required? Describe the standard method of relaying a track on single-line sections.
5. What is the criterion laid down on Indian Railways for track renewal works?
6. What do you understand by mechanized re-laying? How is the same done on the Railways?
7. In brief give the various steps involved in carrying out the manual re-laying of track.
8. Write short notes on the following.
(a) Service life of rails
(b) Sleeper renewals
(c) Track relaying train
(d) Track laying standards