Q Bank for Civil Engineer LDCE Exam- Write Short Notes on (19)

Qus.17. Write Short Note on 

a. Handling of 90 and higher UTS rails. 

Ans:- Higher UTS RAILS (90uts & above are sensitive to handling and require special precautions to avoid damage. The guidelines and instructions in this regard are given in a tabulated statement in the forms of “Avoid” and “Ensue”. Guidelines for handling of 90 UTS & above UTS Rails. 

Items Avoid Ensure Guidelines 

b. Frequency of USFD testing of rails.

Note: (i) frequency of testing of welded 

 (ii)frequency of USFD testing of welds.

c. Cant deficiency & Cant Excess.

Ans:- (i) Cant deficiency occurs when a train travels around a curve at a speed higher than the equilibrium speed . it is the difference between the theoretical cant required for such higher speed and the actual cant provided. In normal – 75mm , special case- 100mm. For A&B route with the permission of CE.

(ii) Cant excess occurs when a train travels around a curve at a speed lower than the equilibrium speed. It is the difference between the actual cant provided and the theoretical cant required for such lower speed. Limiting value – 75mm. 

d. Greasing of ERCs, inserts, liner seats including sealing of liners.

Ans:- 1. Following action therefore , is to be taken while greasing of ERC.

i. Greasing of ERC’s should be done by the keyman in PSC sleeper track. Keyman should carryout greasing of ERCs in a systematic manner from one end at the rate of 20 sleepers (80 clips) per day. Greasing should be planned in such a way that entire length of beat is tackled once in a year, however, in severe corrosion prone areas greasing of ERC’s shall be done once in six months. The severe corrosion prone areas are listed in CE’s circular no 260 to supplement the efforts of keyman, each gang shall also be engaged to grease ERCs in their respective gang beat as it will not be possible for keyman alone to complete the work. In addition to greasing by keyman it shall also form part of systematic maintenance of track by the gang. 

ii. Before greasing & transfer & slightly strike ERC on rail head to cause it to vibrate and distress. For ERC’s which have got stuck into the inserts due to prolonged negligence, use of suitable de-rusting chemicals shall be made to ease out the clips. 

iii. Greasing of ERC’s should not be carried out during extreme o summer and heavy rainfall. At a time ERC’s should not be removed from more than one sleeper. If for any reasons mass lubrication of ERC’s is taken up at least 15 sleepers shall be kept intact between any two sleeper taken up for lubrication of ERC’s at the same time. The ERC’s should be cleaned by wire brush and emery paper. The eye of the insert shall also be cleaned by round wire brush. After cleaning, grease graphite shall be applied to the inside surface of eye of insert and leg of ERC. 

iv. However for increased retentivity of toe load in ERC, the contact surface of ERC needs to be changed periodically. This will facilitate relief from partial permanent set under constant stress accumulation in a particular position for long time. Change in contact points will form new lines of stress forces in ERCs Inside/Outside ERCs should be interchanged and fixed again ERC should be driven back up to correct length. 

3. Toe load of ERCs has been found to be decreasing during service. It is therefore necessary to periodically check the toe load of ERCs to ensure a certain minimum toe load at all time. 

3. Sample size and frequency to be adopted for measurement of toe load of ERCs during services is as mentioned below: 

I. Toe load to be measured on 1 % of ERCs randomly in every 100sleeper (all 4 ERCs to be measured on one sleeper) 

II. Initial testing frequency of ERC to be after 4 years or passage of 200 GMT traffic, Whichever is earlier and afer 2 years or 100 GMT, Whichever is earlier in severe corrosion prone areas. 

III. Subsequent testing will be done every four years or 200 GMT in normal areas and two years or 100 GMT in severe corrosion prone areas, whichever is earlier. However, if 20% or more of sample size records toe-load below 600 kg, both frequency of inspection and sample size are to be doubled. 5. Replacement of ERC:- If 20% or more of sample size records toe load below 400 kg which is to be confirmed by 5% sample size, proposal of through fastening Renewal (TFR) should be initiated. But before initiation of the proposal for through fastening renewal consideration should be given to over all condition of track GMT of route importance priority in the works Programme etc. 

 2. Maintenance of insulated joints.

Ans:- For efficient and trouble free maintenance of insulated joints, following precaution should be taken: 

i. Insulated joints must be maintained as square joints and in any case the distance between staggered joints should not exceed the minimum wheel base of the vehicles. 

ii. Rail ends, where insulated joints are fitted must be square and true. Battered ends must be eliminated by cropping and the gap between the rails, if excessive, must be reduced. 

iii. Fish plates at the joints must be kept tight and the sleepers well packed in the vicinity of the joints to prevent movement of rails, adequate creep anchors should be provided. 

iv. Rail ends must be kept free from dust dirt, sand rust and other foreign materials etc. All rough edges and burners at the rail ends must be removed. 

v. The head of dog-spikes should not be allowed to touch the fish plates: Keys of anti- creep Dearing plates on adjacent sleepers of the insulated joints should not be allowed to touch each other as they may cause short circuiting. Particular care should be taken to ensure that the spikes do not protrude below the sleeper, as this may cause leakage of track circuit current through moisture in ballast. vi. Shims should not be provided at insulated joints. 

vii. To avoid crushing of centre parts of insulation joints creep should be effective assessed. At least one rail length on either side of the insulation joint should be box anchored.