Permanent Way Renewal

Classification of Renewals –

All track renewals can be classified generally into one of the following categories :

(1) Complete Track Renewal (Primary) abbreviated as C.T.R.(P)

(2) Complete Track Renewal (Secondary) abbreviated as C.T.R.(S)

(3) Through Rail Renewal (Primary) abbreviated as T.R.R.(P)

(4) Through Rail Renewal (Secondary) abbreviated as T.R.R. (S)

(5) Through Sleeper Renewal (Primary) abbreviated as T.S.R. (P)

(6) Through Sleeper Renewal (Secondary) abbreviated as T.S.R. (S)

(7) Casual Renewals.

(8) Through Turn-out renewal (TTR)

(9) Through Fitting renewal (TFR)

(10) Through Weld renewal (TWR)

(11) Through Bridge timber renewal (TBTR)

(12) Scattered renewal

(2) Primary renewals are those where only new materials are used and secondary

renewals are those where released serviceable materials are used.

(3) Scattered Renewal- In this case, unserviceable rails, sleepers and fastenings are replaced by identical sections of serviceable and nearly the same vintage track components. These are carried out in isolated locations and not more than 10 rails and/or 250 sleepers in a gang beat in a year. Such renewals are a part of normal maintenance operations.

(4) Casual Renewal- In this case, unserviceable rails, sleepers and fastenings are

replaced by identical sections of serviceable and nearly the same vintage or new track components. These are carried out in isolated locations of continuous but small stretches. Such renewals are not a part of normal maintenance operations and cannot be covered under scattered renewals.

Factors Governing Permanent Way Renewal

(1) Criteria for Rail Renewal - The following are to be considered in connection with the criteria of rail renewals :-

• Incidence of rail fractures/failures.

• Wear on rails.

• Maintainability of track to prescribed standards.

• Expected service life in terms of Gross million tonnes carried.

• Plan based renewals.

(a) Incidence of Rail Fractures/Failures-

A spate of rail fractures on a particular sections having 5 withdrawals of rails per

10 km. in a year due to fracture and/or rail flaws detected ultrasonically falling in

the category of IMR & REM will have priority while deciding rail renewals. In case the rail failures at fishplated/ welded joints are pre-dominant, end cropping with or without welding could be considered.

(b) Wear on Rails –

(i) Limiting Loss of Section– The limiting loss in rail section, as a criterion for recommending rail renewals shall be as under:

Gauge Rail Section Loss in section in percentage B.G. 52 kg /m  and above 6% 90 R 5%

Rail wear may be determined by actual weighment, taking rail profiles at ends after unfishing joints and taking rail profiles with special profile measuring

gadgets.

ii) Wear due to corrosion –

Corrosion beyond 1.5 mm in the web and foot may be taken as the criterion for wear due to corrosion. Existence of the localised corrosion such as corrosion pits, specially on the underside of the foot, acting as stress raisers from the origin of fatigue cracks and would necessitate renewals.

(iii) Vertical Wear –

When the reduction of the depth of the rail head reaches a point beyond which there is a risk of wheel flanges grazing the fish-plates, such rails should be renewed. The limits of vertical wear at which renewals are to be planned are given as below.

VERTICAL WEAR

Vertical wear is to be measured at the centre of the rail either by measuring the height of the worn out rail by calipers or by plotting the profile. In the first case, the wear is the difference between the height of the new rail and the height of the worn out rails.

(iv)Lateral Wear –

Limits of lateral wear from relaying considerations are as under

A typical profile of the worn rail showing the measurement of lateral wear is  shown as below.

Lateral wear is to be measured at 13 to 15 mm. below the rail top table. Worn rail

profile should be recorded and superimposed over new rail profile to find out the lateral wear.

(c) Maintainability of track to prescribed standards

(i) There may be cases, where renewals may be necessary on the following considerations viz.

• Poor running quality of track in spite of extra maintenance labour engaged for maintaining the same,

• Disproportionate cost of maintaining the portion of track in safe condition.

(ii) The condition of rails with regard to hogging/battering,scabbing and wheel burns and other conditions such as excessive corrugation of rail as can be ascertained by visual inspections, which affects the running quality of track, and make the track maintenance difficult and uneconomical, should be taken into account while proposing renewals.

(iii) Renewals of rail due to hogged and battered rails ends should be considered only if other remedies have not been found to be effective.

(d) Renewals on consideration of service life in terms of total G.M.T. of traffic carried – The rail shall be

(iv) planned for through renewal after it has carried the minimum total traffic as shown below –

The service life in terms of total GMT of traffic carried for considering through  rail renewal on the bridge proper and in approaches (upto 100 m on either side) for all the important bridges and such of the major bridges where height of bank is in excess of 4.0 m, all tunnels and their approaches (upto 100 m on either side) shall be half of the GMT specified above.

The released P.way material shall be dealt with in accordance

(f) Plan based Renewals – Renewals to predetermined plan with the objective of modernizing the track structure on selected routes in the quickest possible time may be planned even if it involves premature renewals.

(2) Secondary Rail Renewals –

(a) In the case of Secondary Renewals, if the condition of rail is satisfactory, it is a good practice to crop the rail ends and weld them into SWR and use them in lesser important lines. The rails should be ultrasonically tested before use.

(b) Building up of chipped rail ends by welding will also improve the service life.

(c) The rails released from primary relaying and not fit for use in secondary relayings should be used in sidings

(3) Criteria for Renewal of Sleepers –

Generally a sleeper is serviceable if it can hold gauge, provide satisfactory rail seat and permit rail fastenings being maintained in tight condition, and retain the packing underneath the sleepers. Such sleepers that are not likely to fulfil the above functions even after reconditioning should be renewed. Where resleepering only is justified this should be carried out in continuous stretches, the released serviceable sleepers being utilised for casual renewals elsewhere. On girder bridges when several sleepers are defective, renewals should be carried out for the full span, the released serviceable sleepers being used for casual renewals on the other spans. Before reusing the sleepers, they should be reconditioned.

Proposal for Renewal: - 

Survey of existing site and preparations of plans.

1. Name of work                                      2. Between Stations

3. Location / Kilometers                          4. Materials required with specifications

5. Free rail / SWR / LWR / CWR            6. Welding Material

7. Man and Machinery                             8. Contract / Departmental

9. Period / Duration                                 10. Safety Concern Equipments

11. Release Material                                12. Other requirements if any

13. Justification.

Project report for track renewal works:-

1. Details of Work                                     2. Existing track structure

3. Classification of track materials           4.Proposed track structure

5. Existing/proposed gradient profile       6. Realignment of curves

7. Method of execution                             8. Formation

9. Ballast                                                  10. Transportation of P. Way materials

11. Welding                                        12. Renewal of turnouts, bridge timbers, etc

13. Use of machines                                 14. Contracts

15. Material Planning                              16. Manpower Planning

17. LWR/CWR plans

18. Requirement of speed restrictions, traffic blocks and other material train

19. Monitoring mechanism 20. The detailed project report

Preliminary Works –

1. Supply of ballast at site.

2. Treatment of formation if required.

3. Removal of all obstructions at site like pipeline crossing, cable crossing etc.

4. Arrangement of men and material.

5. Supply of Moorum for repairing cess.

6. Fixing reference pegs for rail levels.

7. Measurement of all vertical and horizontal infringements

8. Marking of Obligatory locations like SEJ’s, bridges, level crossing, points and crossings, cuttings etc.

9. Unloading and spreading the materials at site.

10. Identification and marking of classification on existing materials.

11. Lighting arrangements for night working.

12. Pre-intimation to all concerned departments.

13. Arrangement of protection materials and Engineering indicators boards.

14. Arrangement of small track machines as required.

15. Arrangement of material train and ballast train.

16. Arrangement of traffic block.

Methods of carrying out renewal –

Complete track renewal is carried out by any one of the following methods:–

1. With mechanical equipment.

2. Complete dismantling of old track and relaying with new track (manual).

3. Piecemeal method in which resleepering and rerailing are carried out separately.

Renewal of Track Manually

A. TSR

• Opening of Ballast                                                   Removal of existing fittings

• Removal of old sleepers                                           Insertion of new sleepers

• Fixing fittings and fastening old / new.

• Packing and squaring of sleepers. Boxing and Dressing.

B. TRR

• Removal of fish plates & bolts.                                Removal of existing fittings.

• Removal of old rail.                                                  Insertion of new rail.

• Fixing of fastening with old or new ones.                Fixing of fish plates.

1. General

i) Portal Cranes, commonly referred to as PQRS, are used for mechanized tack renewals. These are loaded on BFRs' and hauled to the site. Normally two portal cranes are deployed for the relaying work at site, while the third one is utilized for pre-assembly of new track panels at the base depot. The third portal crane also acts as a standby in case of breakdown of the portals at site.

ii) Tamping machine should be deployed behind the portal cranes for lifting and tamping of newly laid track.

ii) Minimum block of 2 hours and 30 minutes duration should be arranged.iv) Adequate spares for working of all the machines (Portal Cranes and Tampers etc) should be arranged in advance and regular supply should be ensured.

Working System in Block - There are three systems

PULLING

PUSHING

TRAIN PARTING

Pre-requisites : Following are the pre-requisites for the relaying work with portal cranes:-A well organised and properly laid out base depot is the back bone of relaying by portal cranes. A typical layout of the base depot is shown in figure. Smooth functioning of base depot will ultimately reflect in efficiency and productivity of the relaying work. The base depot is required to cater to the following activities:-

i) Loading/unloading of ballast, if the base depot is also to be used as ballast depot. 

ii) It is desirable to locate the Base Depot at a central place such that the distance of remotest work site on either side does not exceed 60-70 kms. At the same time, the site selected should be accessible by road, there should be electric power supply and watering facilities. The base depot may have facility of entry and exit on both sides from the running line.

iii) For smooth working, the base depot should have atleast three sidings of 500 metres each connected to a shunting neck of 350 metres. Of these, atleast two sidings should be provided with auxiliary track for " movement of portal cranes. iv) It is desirable to illuminate the base depot so that the activities listed in item (i) above can be undertaken safety at night.

v) To strengthen depot working, it is desirable to install a few hand operated/motorised gantry cranes moving on auxiliary tracks in addition to the third portal crane in the depot. Some of these gantry cranes can be of 6.5 metres height from rail level to facilitate rapier to portal cranes.

Following works require road vehicle – a) Unloading of PRC sleepers from the rake and stacking. b) Fabrication of new panels. c) Unloading of released panels from PQRS rake. d) Dismantling of released panels. e) Loading of pre-fabricated new panels. f) Formation of PQRS rake. g) Maintenance of machines. h) Dispatch of released materials.

Pre-Relaying Operations

Following operations should be ensured before actual relaying:-

i) The requisite survey shall be carried out and the longitudinal profile and alignment shall be finalized.

ii) Track may be deep screened one or two days in advance of relaying. The ballast section should be built upto the bottom of sleepers to facilitate relaying. The balance quantity of screened ballast should be trained out after relaying.

iii) Auxiliary track should be laid at 3400 mm gauge keeping the central line same as that of main line track, as shown in figure CST-9 plates or wooden blocks of size 560 × 250 × 125 mm should be used at 1.5 to 2.0 metres distance for laying the auxiliary track. The length of auxiliary track should match with the daily progress of work. 

iv) The level of auxiliary track should be same as that of existing main line track  and must have proper longitudinal and cross levels to avoid derailment of portal cranes. In no case, the auxiliary tack should be more than 50mm higher than the existing track.

v) Removal of ballast from the crib and shoulders upto the bottom level of the sleepers should be ensured.

vi) Full fittings of the old sleepers should be ensured to avoid their falling off while lifting released panels.

vii) The sleeper must be in single piece. Broken sleepers should be removed or replaced in advance.

viii) On girder bridges, the guard rails at the approaches on both ends should be removed temporally.

ix) In case a level crossing is to be encountered, it should be opened in advance. 

x) Proper planning and insertion of Switch Expansion Joints at correct locations should be ensured.

xi) Cutting of LWR/SWR to single rails should be ensured for lifting released panels. Otherwise, replace the existing running rail by service rails for the stretches which are to be relaid in the next day's work.

xii) Temporally disconnect or remove any other permanent obstructions such as cables, signalling rods and any other installations like embedded rail pieces, tie bars etc. to allow unhindered progress of work.

xiii) Availability of under noted equipments should be ensured at site:-

a) One set each of rail cutting and gas cutting equipment in good working condition.

b) Two sets of rail closures of the each rail section being laid, in various sizes from 0.5m to 3m lengths.

c) 4 sets of junction fish plates with bolts.

xiv) Portable walkie-talkie sets should be provided at each relaying site for effective communication between the site of work and the adjoing stations.

xv) Extra number of track panels should be fabricated in the base depot to maintain a buffer stock for one or two days of relaying work so that work at site does not suffer for want of depot working.

Post Relaying Operations

Following post relaying operations should be ensured :-

i) Clearance of track from any obstructions before removal of traffic block. ii) Complete track lifting including their correct positioning & tightness. iii) Proper lifting, packing, ballast regulating and compaction/stabilisation of track to raise the speed of the different stretches. iv) Training out of adequate quantity of ballast over the newly relayed track to full ballast section. Ballast recoupment activity should be properly synchronised with the relaying activity so as to enable raising of speed to normal in three cycles of tamping by on-track tampers. v) Picking up of left over released materials. vi) Dismantling of auxiliary track and relaying the same in advance for the next day's work. vii) Restoration of cables and other fixtures e.g. rails on level crossing which were removed temporarily. viii) Tie tamping machines, BRM and Dynamic Track Stabiliser should be deployed to enable raising of speed to normal. ix) Provision of SEJ as per approved plan. In-situ welding of panels and destressing of LWR should be done after welding of panels.

Track Relaying Train (TRT)

Operations Prior to Development of Machines

i) Base Depot : a) Ensure proper selection of Base Depot site. The base depot for TRT should be centrally located (30-40 kms. lead) m the area of working. It should have water, electricity and communication set up. Also, accommodation for machine and P. way staff should be available. b) Provide sufficient stock of new sleepers, elastic rail clips fastenings, liners and rail pads in the base depot. c) Ensure proper line and level of auxiliary track for 3400/3700 mm gauge portal working. d) 30 nos. BFR's should be modified for one set of TRT. 160 sleepers are loaded in one BFR and about 1500-2000 sleepers should be loaded as required during block. While loading PSC sleepers on special BFRs, wooden battens of 75 mm × 75 mm should be provided between different layers on the outer side of MCI inserts. This will enable gripper to function properly. e) load rail fastening like elastic rail clips, liners and rail pads as required during block.

ii) Condition of sleepers should be seen All corroded and broken steel/CST-9 sleepers should be marked.

iii) Foot by foot survey should be carried out to identify the locations having lateral or longitudinal infringements. There should be no infringement within one metre of sleeper ends.

iv) Adequate ballast should be available before relaying operations start so that tamping and raising of speed is not delayed.

v) Deep screening should be carried out in advance. Excess ballast should be removed and shoulders should be brought down to sleeper level. It should be ensured that the ballast bed is fully consolidated.

vi) Check-rails of the level crossings falling in the range of work should be removed in advance.

vii) All longer fish bolts and joggled fish-plates should be removed from the range of work.

viii) New rails should be unloaded, paired, fishplated or welded in one piece (as required for a day's work) and set at about 1.5 metres from track centre. Rails should be kept on foot with adequate support so that they do not get shifted  during working of the TRT.

ix) All obstructions like creep posts, alignment posts etc. within 1 metre of sleeper end should be removed.

x) All reverse jaw sleepers in case of CST-9 sleeper track should be removed. Alternatively, the lip may be cut by lip cutter so that rail removal is not obstructed.

xi) All longer wooden sleepers from joints be either removed or cut to size in advance of TRT working.

xii) Interlaced sleepers of height different from remaining sleepers should be removed.

xiii) Ensure that the fittings in old track are not jammed and can be removed while working. Loosen them if any problem is anticipated.

xiv) In case o f CST-9 sleepers, gauging should be done in advance to avoid hitting of sleepers by sled assembly during lifting of CST-9 sleepers.

xv) 7 wooden sleepers should be laid in track at a location 5 sleepers behind the rail cut and ballast around them removed for easy placement of plough.

xvi) The location of cut at new site of work should be so planned that it matches with the new rail end for threading at the start of work.

xvii) At location where relaying is to start, two rail pieces of 7.3 metres length are cut and connected together using well greased fishbolts to enable quick opening during block.

xviii) Plan the location of cut in the old track at the closing of work site so that it matches with the rail end of new rail panel. Some extra gap is preferable, as the new rail while threading in is likely to straighten and extend.

xix) walkie-talkie sets for communication should be available with engine driver, Junior/Section, Engineer (P. way) machine staff and adjoining stations. 

xx) Ensure availability of S & T staff to connect- any wire/rodding disturbed during the block, and OHE staff (in electrified section) for opening of temporary bonds and bonding back after the work.

xxi) Ensure removal of OHE bonds before the block. Temporary bonding of the OHE masts should be done by OHE staff while removing these bonds.

xxii) Ensure earth bonding of new rail panels. There should be minimum 3 bonds in each panel length of 300 metres.

xxiii) Ensure removal of alternate keys in case of CST-9 sleepers and inside alternate keys in case of ST sleepers. The remaining keys should be checked for easy removal.

xxiv) Existing small nos. of PSC sleepers (2 rail lengths) should be replaced with

wooden sleepers to avoid loss of time while working.

xxv) High temperature destressing of the old tack should be carried out as provided

Manual Operations During The Block :

i) Shield hydraulic pipes and other moving parts of the TRT so that in case of any mishap, these do not hit OHE mast.

 ii) Take OHE block, if staff is required to climb on top of the machine for repairs etc. in case of any break down. 

iii) Ensure proper track protection at the site of work, look-out men and hooter in good working order to give warning for train approaching on the other line. 

iv) Utmost caution should be taken while lowering and raising Clamp in order to avoid infringement to the adjacent line. 

Post Block Operations:

Ballasting of the track should be done immediately after track relaying operation.

 ii) Then Ballast Regulator, Tie Tamping machine and Dynamic Track Stabilizers should be deployed to enable raising of speed to normal in shortest possible time.

iii) In-situ welding of isolated joints should be done before restoration of speed to normal.

iv)Switch Expansion Joints should be provided at locations as per approved LWR/CWR plans.

v) Check rails should be provided at level crossing after final tamping of the track. vi) Destressing of LWR should be done immediately after welding the rail panels to long welded rails.

Precautions

The following precaution should be taken for TRT working :-

i) It should be ensured that the ballast bed of newly deep screened track is fully consolidated and there is no fear of settlement of ballast bed during TRT working. 

ii) Do not unload excess ballast in advance as this causes excessive drag on the machine traction. 

iii) Do not open out all keys in advance. This should be opened up only as the machine rake approaches the planned site of renewal. 

iv) Do not stand very close to the machine or modified BFRs and do not touch the gantry rails. 

v) Do not stand on the BFR while the gantry is moving over with new/old sleepers. 

vi) Do not allow the gantry to stand with its wheels on different BFRs.

vii) Without work, do not sit on the rail seat meant for liner/rubber pad placement. 

viii) Do not climb to the top of TRT without OHE block in electrified section.

Points And Crossings Changing Machine (T-28)

Pre-Block Operations

Following preparations are to be made:-

 i) New turnout should be assembled using Jib Crane near the site of turnout to be replaced. The fittings of assembled turnout should be completed and properly tightened If suitable location is not available near by, assembly may be done away from site and then transportation can be done with the help of trolleys. Infringements on the way should be checked and movement with slewing accordingly may be planned.

 ii) The assembled turnout should be loaded on trolleys for transportation.

 iii) Rails on either side of existing turnout should be of the same section as that of new turnout.

iv) Deep screening of turnout portion should be done. Ensure required cushion and proper drainage. Rail levels should be taken for sufficient length on either side of turn out. Proposed rail profile should be plotted both for main line and loop line.

 v) Point machines should be disengaged and turnout should be non-interlocked before taking up its replacement.

vi) Ballast from crib and shoulder of sleepers should be removed upto sleeper bottom for full turnout length.

vii) 60 wooden blocks, each approximately 60 cm long, should be kept ready for facilitating passage of crawler on the obstacles.

 viii) 4 nos. of rail pieces each 70 cm long should be kept ready for housing; below the rail wheels of the crane.

ix) Jumpering of both ends of the turnout should be done by electrical staff before lifting and removing of existing turnout.

 x) Adequate arrangements should be made for protection of the line involved and adjacent lines while the machine is working.

 xi) Fish bolts should be lubricated and worked to facilitate easy removal during block. xii) Location where clamp of each crane will hold the crossing and switch portion for lifting should be marked on the assembled turnout.

 Operations During Block 

i) Immediately after getting traffic block, the fish bolts of existing turnouts should be opened.

 ii) Both cranes should be traversed and brought in position for handling the existing turnout at the demarcated position.

iii) Old turnout should be lifted by cranes and traversed to suitable location for further dismantling. Actual dismantling of turnout is done manually after the block.

 iv) The crane should be traversed to the pre-assembled concrete sleeper turnout and both the cranes should be taken to demarcated position on turnout.

 v) Simultaneously, the gangs should scarify the ballast from the location where the turnout has been removed. The ballast bed is lowered to accommodate extra height in case of concrete sleepers.

vi) The crawler side frame of the cranes should be spread suitably in stages to accommodate the length of the turnout sleepers on their demarcated locations for each crane.

vii) Pre-fabricated turnout should be held by the crane. The cranes with the panel be traversed across in stages and brought to the location of laying. The turnout is laid in position and fish plates are bolted to the existing track.

viii) One crane is traversed on the track and the second is utilised for final alignment of turnout. After placing the turnout, gangs should fill back the ballast manually.

Post Block Operations:

 i) Ballast deficiency should be made good by putting additional ballast. profiling and boxing of ballast should be done.

ii) The turnout should be tamped with the help of UNIMAT machine. Both alignment and levels should be corrected while tamping the turnout.

iii) The turnout may be interlocked and point machine engaged immediately after laying the turnout.

iv) Damage to the cess during block operation should be made good.

v) Provision of proper earthing points should be ensured by the Electrical staff.