Railway Building Engineering Practice Exam paper
Question and Model Answers
Q.5 Attempt any TWO of the following.
a) Explain the causes of creep of rail. Suggest preventive measures against it.
Ans :- Causes of creep:
1. Wave action or Wave Theory:
Wave motion is set-up in a resilient track by the moving wheel loads. The train
wheels causes depression under themselves forming lifts or crests. With movement of
wheels, the lifts on front of the moving wheels are carried forward whereas the lifts at
the rear of the moving wheels get back to their normal position. Thus, the rails are pushed forward which causes creep in the forward direction.
2. Percussion Theory:
The rail creep is due to impact of wheels at the end of facing rail at each fish plate
joint as shown in figure. When the wheel pass over such a rail joint the trailing rail
depresses down and the wheel give impact to the end of facing rail, which results
creep in forward direction.
3. Accelerating or Starting of a train:
At the time of accelerating or starting of a train, the engine wheels give a backward
thrust which tends to push the rails backwards, causing creep in the backward
direction.
4. De-accelerating or Stopping the train:
When the train is de-accelerated or stopped, the braking effect tends to push the rail
forward. Thus, causing the creep in the forward direction.
5. Expansion and contraction of rails due to variation in
temperature:
Creep may also be caused due to unequal expansion, contraction of rails due to
variation in temperature.
6. Intensities of Traffic:
In a single line track, the creep will be resulted in the direction of heavy intensity of
traffic. In a double line track, the creep occurs in both the tracks in the direction of
movement of trains.
7. Alignment of the track:
Creep is greater on curved portion than on straight portion of the track.
8. Gradient of the track:
Creep is more on a track with steep gradient, particularly, if the trains move
downwards with heavy loads.
Creep Prevention:
1. Pulling back the rails.
2. Use of steel sleepers.
3. Using Anchors/Anti-creepers.
4. By increasing number of sleepers per rail length.
b) Explain the necessity of tilting of rail with neat sketch
Ans :- In case the rail of track are placed in vertical position ,the top surface will not come in full contact with the treads of wheels of a train due to coning of wheels and the pressure of wheels will always be exerted near the inner edges of the rails. Therefore, the rails will wear out quickly .To make full contact of top surface and thereby reducing the wear of rails in this way, these are placed at an inward slope of 1 in 20.which is known as tilting of rails. The tilting of rail is achieved by providing a cut in the wooden sleeper called as “Adzing”. Canted bearing plates can also be used in wooden sleepers to provide tilting of rails. Steel, CI and PSC sleepers have in built slope on the bearing surface to provide tilting of rails.
c) Explain the duties of following personnel’s in rail track maintenance:
(i) Permanent Way Inspector
(ii) Gang Mate
(iii) Key Man
Ans :-
Duties of permanent way inspector -
1. The duties of permanent way inspector are as follows;
2. The PWI is personally responsible for maintaining the track in good condition for
the passage of trains. For this purpose, he travels over the track by push trolley and
watches the defects of the track and arranges the repair of the defective track by his
gang.
3. He is responsible to carry out the renewals of rails and sleepers.
4. He should maintain the record of wear of rails in his section. He should check out
the programme for lubrication of rail joints in such a way that the entire rail joint
are lubricated on a year during winter season.
5. He is responsible to maintain the correct gauge, super elevation on curves and
removal of creep etc.
6. He should supervise the work of his gang regularly.
7. He should see the welfare of his gang man.
8. Level crossing under his charge must be maintained in perfect condition. During
this visit to level crossing, he should check the working of gateman also. If necessary
he should issue instructions to the gateman.
9. At the time of accident, he is responsible to store the traffic in the shortest
possible time. He should also find out the causes of accident.
10. He should prepare the estimates of the maintenance work and should report the
progress to his seniors.
Duties of gang mate-
1. Gang mate means the person in charge of gang of work men employed on
permanent way.
2. He is responsible for the maintenance of track.
3. It is his duty to arrange for tools and other requirement for his gang.
4. He has to allot duties to each of his gang man and to check their work.
5. He has to maintain record of work, reports of key man.
Duties of Keyman-
1.The position of a Keyman in his gang is next to the Gangmate and hence, in his
absence the Keyman is to perform his duties
2. He is responsible for the upkeep of all fastening and rail joints in the track of his
section.
3. He is to walk on the whole section to inspect fastening and joints every day.
4. He is to tight all the fittings like fish bolts, spikes, sleepers, keys etc. found loose
during his inspection.
5. He should grease fish plates and oil fish bolts.
6. He should open and refit all joints at least once in a year.
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