Q Bank for Civil Engineer LDCE Exam- Write Short Notes on (27)

Q No.9: Write short notes on any five of the following: 

(a) Types of L-Xing 

(b) Elimination of Unmanned L-Xings 

(c) Duties of Gateman 

(d) Frequency of USFD Testing of Rails 

(e) Fracture Repairs in LWR Track 

(f) Design mode working of CSM 

(g) Track tolerances for BG Track

(a) Type of L-Xing :- L-Xings have been classified in various categories in consultation with road authorities depending upon the volume of Road/Rail Traffic passing on them and their visibility conditions. These are classified as under:- 

(b) Elimination of Unmanned L-Xings :- Unmanned L-Xing are the safety hazard for railway traffic as well as for road users, efforts should be made to eliminate them. Unmanned L-Xing may be eliminating by following method. 

 i. By Construction of ROB. 

ii. By Construction of RUB. 

iii. By Construction of LHS. 

iv. By merger in nearby L-Xing. 

iv. By closing due to Low TVU

(c) Duties of Gateman :- Gateman is an important person and he should ensure safety at level crossing by performing following duties. 

i. Alertness: He should be alert and be prepared to take immediate action in case of an emergency. The keys of gate should be on his person. 

 ii. Position during passages of train: The gateman should stand facing the track on the gate Lodge side of the approaching train. 

iii. The Gateman should ensure that gate lamps and lamps of all location are lighted and Kept burning continuously from sun set to sun rise. 

iv. No Gateman should leave his gate unless another gateman has taken charge of it. If it is Necessary to leave his gate in case of an emergency, he should close and lock the gates against pubic road before leaving the gate. 

v. The Gateman should ensure that the channels for the flanges of the wheels are kept clear. 

vi. The gateman should keep the road surface well watered and rammed. 

vii. The gateman should report all unusual occurrences including the damage of gate to nearest station master and the P.W.I. 

viii. Parting of train: If a gateman notices that the train has parted, he shall not show a stop hand signal to the driver but shall endeavor to attract the attention of driver and guard by Shouting, gesticulating or by other means. 

 ix. Protection of level crossing in case of an emergency: He should protect the track as Per protection diagram.

(d) Frequency of USFD testing of rails:- USFD testing is very important activity as by this mean various flaws developed in the rails are being detecting in the advance. Frequency of USFD testing is depends upon GMT of the sections. 

 At present frequency is as under. 

 

(e) Fracture repairs in LWR track:- If there is any fracture takes place in LWR/CWR immediate action shall be taken by the official detected the fracture. The repair shall be carried out in 4 stages as described below. 

 i. Emergency repair to pass the traffic immediately. 

ii. Temporary repairs 

iii. Permanent Repairs

iv. De-Stressing. 

i) Emergency Repair: The fracture rail shall be joined by using ordinary/joggled fish plate with the help of clamps, if the gap at the fracture does not exceed 30mm insertion of any closer of the rail piece is not necessary, the first train should be passed at a speed of stop dead and 10 KMPH further subsequent trains should be allowed at 20 KMPH 

ii) Temporary repairs: During block fracture rails should be replaced by using 6.5 mtr. rail. The cutting of rail should be done with the assessment that total length of rail removed should be equal to inserted rail including provision of welding. After this speed to be raised to 30 KMPH. 

iii) Permanent Repairs: After taking proper block one joint should be weld first and thereafter second joint should be welded with the help of rail tensor. 

iv) De-Stressing: De-Stressing should be done at least equal to the breathing length i.e. about 70 mtr on either side of the fracture.

(f) Design mode working of CSM:- For achieving good track geometric packing of the PRC track should be done by using CSM in design mode. However if the variation in level and alignment is very less than CSM temping may be done by using smoothing mode. In design mode temping rail levels of a particular section of track are recorded by using leveling instrument final levels along with gradients and vertical curves are to be decided carefully. The required lift and slew are finally recorded on every alternate sleeper. Temping should be carried out by entering the lift and slew at the front tower by adopting design mode of leveling and lining. By design mode temping desired track geometry can be achieved

(g) Track Tolerances for BG Track:- The safety and comfort of rail travel depend primarily on the track geometry and the standard to which it has been maintained. It is not possible in actual practice to obtain a flawless and perfect track; Parameters governing the track geometry have always certain variation. Track tolerances may be defined as the limits of variability of various parameters pertaining to track geometry. The Type of track tolerances are as under:- 

i. New track tolerances. 

ii. Maintenance tolerances. 

iii. Index tolerances. 

iv. Good riding tolerances. 

v. Slow down tolerances. 

vi. Safety tolerances. The above all tolerances are define by magnitude of track parameters i.e. alignment, defect, twist, Gauge various and unevenness.