Write Short Notes on
2.
(a) Pre & post tamping operations for TRT machines. TRT machine is being used for carrying out TRR and TSR simultaneously in the field.
Pre-Tamping operation :
i. Field survey should be carried out to determine existing profile of track and to decide the general lift. In case of design mode working, the survey should be done as per guidelines.
ii. The beginning and the end of curves/ transition curves should be marked on sleepers. Super- elevation and slew should e marked on alternate sleepers to act as guide for the operator.
iii. Low cess should be made-up.
iv. Track drainage should be improved for better receptivity of packing. Pumping locations should be attended. Rounded ballast should be replaced with clean and angular ballast.
v. Deficient fittings and fastenings should be made food and all fittings and fastenings likem fish bolts. Keys, cotters, loose jaws elastic rail clips, pads etc. should be properly tightened. Worn out fittings should be replaced. vi. Broken and damaged sleepers shall be replaced.
vii. Distressing of rails, adjustment of creep, expansion gaps in joints, buffer rails and SEJs etc, if necessary, shall be carried out.
POST TAMPING OPERATIONS:- The section engineer (P.Way) shall pay attention to the following items:-
i. Checking and tightening of loose fittings.
ii. Replacement of broken fittings.
iii. The ballast shall be dressed neatly; proper consolidation of ballast between the sleepers shall be done.
iv. If the recorder is not available parameters of at least four stretches of 25 sleepers each per kilometer of tamped track should be recorded, in addition the versins and super- elevation of curves shall be recorded for at least ten stations at a specified chord length.
iv. While working in LWR territory, the provisions of manual of instructions on long welded rails-1996 should be followed.
iv. The fixture like check rails removed during pre-tamping operation should be restored.
(b) Describe procedure of Deep screening in single rail section, SWR & LWR, pre caution to be observed at site also to be mentioned.
Ans. Due to presence of bad formation abrasion and attrition of ballast, impact loads excessive rainfall, ballast gets chocked up and track drainage is impaired. At this stage entire ballast under sleeper and crib right up to formation level/sub ballast level is removed to improve drainage and running quality of tack, the process is called Deep screening. It can be carried out at following locations:
1. Deep screening shall be done after 500GMT or 10 years whichever is earlier. However Deep screening can be carried out when clean cushion ballast is less than 150mm to ensure dropper machine temping.
2. Prior to CTR
3. Prior to TSR
4. Due to caking of Ballast resulting into unsatisfactory riding.
5. Need of intermediate Deep screening is to be decided by C.T.E. Process of Deep screening in track other than LWR is as below.
i. Longitudinal section of the track shall be prepared indicating the rail level at every 30 m. including changes of grades obligatory points like culverts, Bridges, Tunnels, Level crossing points & Crossing etc.
ii. In station yards on run through lines x-section at every 50 m. shall be plotted indicating
platforms levels, Rail Levels etc.
iii. On the bases of L-section and x-section the Final level shell be decided keeping in view the
a. Depth of Ballast cushion to be provided
b. Lifting and lowering track
c. Possibility of elimination humps, sags and unevenness in the existing longitudinal
section.
Screening operation:-
1. The work of Deep Screening shall be done under the supervision of authorized supervision having
compliancy certificate.
2. The rail direction of Deep screening should be in opposite direction of traffic. A B C D 1 2 3
a. Remove ballast from ‘A’, B on either side sleeper ‘I’ down to final formation level and provide wooden block to support the rail level for passing Train.
b. Remove ballast from Under ‘1’ down to final track level sub ballast level, screen ballast put back under sleeper ‘1’ and pack.
c. Remove wooden block from space “A”.
d. Remove ballast from space ‘c’ down to formation level, screen it and place in space support the rail in space ‘C’ with wooden blocks. e. Remove ballast from under sleeper ‘2’ down to formation level. f. Provide screened ballast under sleeper ‘2’ and pack. g. Remove ballast from space ‘D’ down to formation level, screen it and place in space ‘B’ up to bottom of sleeper. Take ballast from quantity outside and screen the h. Remove ballast from under sleeper’3’ and so on till the entire length is provided with screened ballast up to bottom of sleepers. i. Lift the track to provide additional cushion where required. Pack the track in final passion and box. Precautions during the work Following precaution should be observed strictly to avoid any undesirable situation during the deep screening work-
i. No unscreened length is left in between the screened portion as it may lead to uneven
settlement.
ii. When ballast is being removed from any sleeper, invariably there will be at least 4 fully supported sleepers In between and next sleeper tackled. iii. Lifting shall be limited to 50mm at a time .
iv. Working tools such as beater, crow bar and ballast etc. is removed before the passage of traffic.
v. Rail is supported properly on wooden blocks before any traffic is allowed to passes. During manual deep screening the S/R will be as under:-
Deep screening operation in LWR track:-
Precautions during Deep Screening:-
i. Ballast cleaning machine, Tamping machine and dynamic Track stabilizes shall as for as possible, be deployed in one consist.
ii. Temperature records of the section when deep screening is to be undertaken, shall be studies for the previous and the current year. The maximum and minimum rail temperature attainable during the period of deep screening ad during the period of consolidation shall be estimated.
a. If range of rail temperature falls within Td + 10 degree to Td- 20 degree, deep screening may be done without cutting or temporary distressing.
b. If range of rail temperature fall outside
(a) above Temporary deep screening shall be carried out 10 degree below the maximum rail temperature likely to be attained during the period of work.
c. Wherever rail renewals are being carried out, LWR/CWR may be converted into three rail panels and deep screening done.
iii. Constant monitoring of rail temperature shall be done during the progress of work should the temperature rise more than 10 degree above Td/temporary distressing temperature, adequate precaution shall be taken including another round of temporary distressing .
iv If min. rail temp. falls TD=30 degree, cold weather patrolling is to be introduced to detect/guard against rail fractures.
V Deep screening of LWR may done from one end of LWR to another end.
Vi The Deep screening in LWR is to be carried preferably by ballast.
The Speed Restriction schedule be as under:-
The period mentioned in the schedules shown above is the minimum and can be suitably increased to suit local condition of the track consolidation. Precaution during BCM working at site --- Precaution to be taken during deep screening of track by BCM followed by TTM and DTS machines; (The section can be opened at a speed of 45 kmph subject to fulfilling of conditions as stipulate
d). i.All precautions laid down in LWR manual shall be strictly followed.
ii.Hard sal wood blocks of size 600 x 300 x 300mm (six numbers) duly end bounded shall be arranged for supporting ends of three adjoining sleepers where cutter bar is left in the track and remains untamed.
iii.Sleepers of cutter bar area shall be manually packed and ballast under cutter bar location sleeper shall be removed only half an hour before the expected traffic block. Adequate care shall be taken to ensure that wooden blocks are not dislodged before arrival of BCM at site.
iv.Fish plated joint shall not be located in cutter bar location.
v.Ramp shall not be located in locations like level crossing, girder bridge, transition portion of curve etc. It shall be kept minimum two rail length away. vi.In case of fracture or cut in CWR/LWR, a speed restriction of 20 Km/h shall be imposed till it is repaired.
vii.In case of malfunctioning of TTM and /or DTS, deep screening shall be stopped and track which has not been tamped and stabilized shall be attended manually by ballast ramming.
viii.In case of non- availability of traffic block on subsequent days of deep screening by BCM, speed restrictions shall be Imposed and relaxed as per procedure. ix.When BRM is not deployed, adequate track men shall be deputed to recoup ballast, particularly in shoulder and maintain ballast profile after machine working.
x.Lifting of track shall be resorted after ensuring adequate availability of ballast for maintaining ballast profile for planned lifting.
xi.Adequate arrangements for supply and training out of ballast prior to deep screening should e made.
Special care shall be taken by deploying watchman on stretches overdue for rail renewal.
(C ) Procedure of distressing with rail tensor in LWR & CWR territory. Distressing of LWR/CWR shall be done whenever required as per condition and behavior of LWR/CWR. But in any case it shall be done at least once in 5 years as per CE circular 300.
Distressing is to be done when – Abnormal behavior of LWR/CWR whenever gets manifested in one or more of the following, distressing shall be undertaken as per procedure. i. When the gap observed at SEJ. a. Differs beyond limits. The gaps between the reference mark and tongue rail tip/stock rail corner at various tail temperatures shall not differ by more than +/-10 mm from the theoretical range. Where fish plated or SWP track is joined on one side of SEJ, the gap between the reference mark and tongue rail tip/stock rail corner on LWR/CWR side shall not differ by more than +/- 10 mm from the theoretical range. Exceeds the maximum designed gap of SEJ b. When stock/tongue rail crosses the mean position. After special maintenance operations such as:
• Through fittings renewal
• Deep screening/mechanized cleaning of ballast
• Lowering/lifting of track
• Major realignment of curves
• Sleeper renewal other than casual renewals
• Rehabilitation of bridges and formation causing disturbance to track
ii. After restoration of track following an unusual occurrence.
ii. If number of locations where temporary repairs have been done exceed three per km. Distressing of CWR shall be done by cutting it into LWRs of about 1 km length which shall be joined after distressing.
DESTRESSING OF LWR
General
i. The work of distressing shall be done during a traffic block under the personal supervision of a PWI.
ii. It is preferable to impose a speed restriction of 30 km/h before actually obtaining the traffic block and to loosen/remove fastenings on alternate sleepers to reduce total duration of the traffic block. Sequence of operation The procedure to be adopted for distressing consists of the following steps:-
i. Remove impediments to free movement of rail such as rail anchors, guard rails, check rails etc.
ii. Create gap of about 1 metre at the centre of LWR during a traffic block and insert a closure rail there at a restricted speed.
iii. Mark anchor lengths at either end of the proposed LWR.
iv. Erect marker pillars at the ends of anchor lengths on either side and at 100 metre intervals thereafter.
v. Obtain a traffic bloc when tp is less than the desired installation temperature (tp ), remove the closure rail at the centre and unfasten the full length of rails leaving only the anchor lengths at either end. Mount the rails on the rollers. Side rollers shall also be used while undertaking distressing on curved track. Side supports on the inside of curve should be spaced at every nth sleeper, Where, n= Radius of curve (R) x No. of sleepers per rail length 50 x (to-tp ) Outside supports shall be used in addition at the rate of one for every three inside supports.
vi) Fix rail tensor across the gap at the centre ad apply tension so as to get the required amount of
extension.
vii) Re- fasten the rail starting from the anchor lengths at either end after removing the rollers progressively and adjusting tension at the rail tensor to make sure that the required extension has
been achieved at each marker pilar. put paints marks on either side of the gap at the centre , spanning over the gap at a distance of 6.5 metre. Inset a coosure rail of a length equal to (6.5 metre-2 gaps for welding + 1 mm for saw cut ends) and clamp.
ix) Release and remove the rail tensor.
x) During another traffic block, weld both the joints of the closure rail at the centre.
xi) Equalize stress at the centre and at the anchor lengths.
DESTRESSING OPERATION OF LWR WITH THE USE OF RAIL TENSORS For distressing of LWR with the use of rail tensor, the following procedure shall be adopted:-
i. During the first traffic bloc, create a gap of 1 metre at location ‘B’ i.e. centres of LWR. Introduced rail closure as required and fasten with special fishplates and clamps. Allow traffic at restricted speed.
ii. Mark the anchor length A1 A2 and C1 C2 each equal to Ia at either end of the length A2 C2 to be distressed.
iii. Erect marker pillers W1 W2 etc., on each of the length A2 B and C2 B. transfer the marks Wo onto the rail foot. The distance WoW1W1W2 etc. shall be marked at about 100 metre intervals, the distance from the previous pillars and the last pillar WB may be less than 100 metre. iv. During the second traffic block, when tp is less than the desired to, destressing operation shall be carried out for the lengths A2B and C2 B as described below:-
a) Remove the closure rail from location ‘B’ Unfasten and mount on rollers the portion from A2C2. b) Fix the rail tensor across the gap at ‘B’ and apply tension so as to contain some movement at Wo to remove any kinks or misalignment and to minimize the friction in the rollers etc. Release the tension and note the movement Yo at Wo.
c) Transfer marks W1,W2 ........ onto the rail foot and note temperature tp.
d) Calculate the required movement at W1 as under :-
Movement at W1=Yo+ elongation of length WoW1 (L) due to temperature difference (to-tp)= Yo= Lα(to-tp)
Calculate the required movement at W2 as under :-
Movement W2=movement at W1+ elongation of length W1W2(l) due to temperature difference (to-tp). Similarly
calculate the required movements successively at each of the transferred marks referred at ©above on the rail foot on the side away from the tensor. Apply the tension by means of rail tensor till the mark of required extension comes opposite to the mark on the marker pillar W
1. Fasten down the segment WoW1. Then check at W2,bring the mark of required extension at this location opposite to the mark on the marker pillar W2, by adjusting the tensor either by reducing or increasing tension and fasten down the segment W1W
2. Similarly , check the remaining marks, adjust the tension as required and fasten down each segment before proceeding to the next.
ii) Only one value of tp has to be taken at the time of marking W1,W2 etc. on the rail foot. The values of tp is not required to be taken thereafter. The variation of temperature, if any during the distressing operation shall automatically be taken care of by reducing or increasing the tensile force from the tensor, while coinciding the reference mark on rail with the corresponding mark on pillars. iii) if for any reason, both the length A2B and C2B cannot be fastened down simultaneously, the final adjustment in pull and fastening down of individual segments may be done in series, first from A2 to B and then, from C2 to B.
e) After the fastening down of the last length A2B and C2B is completed, make a paint mark near free end of one rail at a distance of (6.5 metre +2x25mm-1mm), measured from the end of the other rail across the gap spanned by the rail tensor.
f) Remove the tensor, close the 1 metre gap temporarily and allow traffic at restricted speed.
v) During another traffic block, cut the rail at the paint mark, insert a rail closer of length exactly equal to 6.5 metre and weld one end thereof. If the gap at the other end is also 25mm, it can be welded in the same block. Otherwise fasten with special fishplates and clamps and allow traffic at restricted speed. In the latter case, during a subsequent block when tp is not greater than to, release rail fastening on either side to the required extent and pull the rails with rail tensor to get the desired gap of 25mm refasten the rail and weld the joint. Release the tensor after a lapse of a minimum of 20 minutes after pouring of the weld metal.
vi) During a sun sequent traffic block, when tp is less than td, equalize the forces in the rail by releasing the fastenings over a length of 100metre on either side of location ‘B’ and rapping with wooden mallets etc. Fasten down the rail and allow traffic.
vii) During another traffic block, when tp is within the range of temperature destress the end 100 metre from SEJ. Thereafter ,weld th closure rail next to SEJ duly ensuring setting of the SEJ.
(d) Elimination of level crossing. Enumerate various methods.
The level crossings can be eliminated by following methods subject to:
1.Consent of district administration: The consent of district administration for elimination of LC by closure/diversion/RUB/ROB will be processed and obtained.
2.Sanction of commissioner of Railway safety for closure of manned level crossings is required before closure of L-xing.
HOWEVER: By following method the LC, manned or unmanned can be eliminated
1) By provision of ROB/RUB/LHS
2) By merger with adjacent L-xing
3) By direct closure due to low TVU.
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