Track Lateral Stability

Transcription

1 Discipline: Engineering (Track & Civil) Categry: Cde f Practice Track Lateral Stability Sectin 6 Applicability ARTC Netwrk Wide Primary Surce Dcument Status Versin Date Reviewed Prepared by Reviewed by Endrsed Apprved Jul 13 Standards Stakehlders Manager Standards General Manager Technical Standards & Envirnment 22/07/2013 Amendment Recrd Versin Date Reviewed Clause Descriptin f Amendment Nv 09 Implementatin draft f netwrk wide dcument which is an amalgamatin f the CP fr SA/WA & Vic and NSW requirements Jun 10 Banner added regarding mandatry requirements in ther dcuments and alternative interpretatins Nv 11 Banner added regarding elements f RISSB Natinal CP being incrprated Jun 12 Terminlgy adjusted fr cnsistency with AS 7643 and Wrk Instructins. Sme cntent frm Engineering Instructins incrprated. Als minr editrial changes Sep Added measurement f stress free temperature as an alternative t mnitring rail creep. Australian Rail Track Crpratin Limited 2013 Disclaimer: This dcument has been prepared by ARTC fr internal use and may nt be relied n by any ther party withut ARTC s prir written cnsent. Use f this dcument shall be subject t the terms f the relevant cntract with ARTC. ARTC and its emplyees shall have n liability t unauthrised users f the infrmatin fr any lss, damage, cst r expense incurred r arising by reasn f an unauthrised user using r relying upn the infrmatin in this dcument, whether caused by errr, negligence, missin r misrepresentatin in this dcument. This dcument is uncntrlled when printed. Authrised users f this dcument shuld visit ARTC s intranet r extranet ( t access the latest versin f this dcument.

2 Jul Inclusin f general inspectin infrmatin remved frm ETM Managing Track Stability Cncrete Sleepered Track. This ARTC CP has drawn n the Rail Industry Safety and Standards Bard (RISSB) Natinal Cde f Practice Vlume 4, Track and Civil Infrastructure, but is nt identical. The ARTC CP has been subject t Risk Assessment as required by the varius State Rail Safety Regulatrs. The results f these risk assessments have made it necessary t deviate frm the RISSB CP in sme areas. ARTC maintains traceability f the differences. Versin 2.5 Date f last revisin: 19 Jul 13 Page 2 f 8

3 Cntents Cntents 6 Sectin 6: Track Lateral Stability Design and Rating Design Stress Free Temperature in Track with CWR Maintenance Creep Mnitring Pints Inspectin and Assessment Management f Special Lcatins Scheduled Track Lateral Stability Inspectins Further Guidelines fr General Inspectins Un-scheduled Track Lateral Stability Inspectin Assessment and Actins... 8 Versin 2.5 Date f last revisin: 19 Jul 13 Page 3 f 8

4 Design and Rating Mandatry requirements als exist in ther dcuments. Where alternative interpretatins ccur, the Manager Standards shall be infrmed s the ambiguity can be remved. Pending remval f the ambiguity the interpretatin with the safest utcme shall be adpted. 6 Sectin 6: Track Lateral Stability 6.1 Design and Rating Design Stress Free Temperature in Track with CWR The design rail stress free temperature is 38 C. Prcedures fr the stress adjustment f rail t achieve the design stress free temperature must be apprved by ARTC. 6.2 Maintenance Creep Mnitring Pints Timber/Steel Sleepered Track Tracks welded int CWR are shuld be prvided with creep mnitring facilities lcated at every kilmetre and half kilmetre pst and als at ther significant pints f the track that ARTC cnsiders apprpriate. Where required, mnitring pints are t be prvided as punch marks n the uter sides f bth rail heads and are t be recvered by means f a nail r punch marks in suitable fixtures such as psts r verhead structures n each side f the track in such lcatins that a check string can be stretched abve the rails between the recvery pints. Where creep mnuments are nt installed, the direct measurement f stress free temperature may be used t mnitr the track buckling frces. Cncrete Sleepered Track Track cnstructin types that are knwn t prvide very gd resistance t lngitudinal rail mvement (e.g. CWR track with cncrete sleepers and resilient fastenings) will nt usually necessitate rail creep mnitring and cntrl measures. Practices fr the measurement f rail creep shuld be cnsidered and take int accunt the influence f fixed pints in the track. 6.3 Inspectin and Assessment Management f Special Lcatins Track sectins prne t (i.e. with a histry f) lateral track instability r pull-apart failures shall be identified and managed as special lcatins Scheduled Track Lateral Stability Inspectins a) Patrl inspectin The interval between track patrl inspectins shall nt exceed 7 days in the high temperature seasn apprpriate t the area r as specified therwise by ARTC e.g. in an apprved Technical Maintenance Plan. These inspectins shall keep a lkut fr defects and cnditins (i.e. indicatrs f a defect) that may affect, r indicate prblems with the lateral stability f the track (e.g. evidence f excessive rail creep, degraded ballast cnditins, lngitudinal sleeper mvement) including: (i) Lateral misalignments including "kicks" in tangent track. Versin 2.5 Date f last revisin: 19 Jul 13 Page 4 f 8

5 Inspectin and Assessment (ii) (iii) (iv) (v) Curved track sectins with sharp r flat curvature. Rail breaks (i.e. excessive lcal tensile rail stresses cntributing t pull-aparts). Indicatins f incrrect rail stress, fr example: (A) (B) (C) Twists and wriggles in the rail at temperatures well belw design stress free, which may indicate the rail is in cmpressin. Marks n the rail indicating lngitudinal mvement f the rail (creep) thrugh the fastening assemblies. Track mvement indicated by fr example: Gaps between sleepers and ballast (laterally and lngitudinally) Heaped ballast Skewed sleepers Other bvius defects r cnditins that may affect lateral track stability. In additin, track patrl inspectins leading up t and during the high temperature seasn must particularly check curves that: (i) (ii) (iii) Have a histry f winter pull-in. Have been disturbed by resleepering r resurfacing. Appear t have pulled in. Sectins f track with suspected defects that may cntribute t inadequate lateral track stability shuld be subject t general inspectin. The speed at which the inspectin is carried ut shuld be cnsistent with the lcal cnditins and the full scpe f the inspectin being carried ut (e.g. the type and number f ther infrastructure elements being inspected). Particular attentin shuld be paid t cnditins at special lcatins such as fixed pints. b) General inspectins Scheduled general inspectins shall be f sufficient detail t bserve the track cnditins and changes in cnditin that affect the vulnerability f the track t future high (and lw) temperature events. The inspectins shuld include identificatin f defects and cnditins as described fr patrl inspectins. They shuld als determine the cnditin f the general track structure in terms f its cntributin t any reduced lateral strength including fr example: (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) (xi) (xii) Pr track gemetry; Rail, weld and jint misalignment; Frzen jints and jint regulatin fr mechanically jinted track; Track structure changes particularly where the interface between tw types f track structure may cause a significant change in restraint against rail creep, buckling strength r the temperature stresses induced in the track (e.g. a change frm timber sleepers t cncrete sleepers, a change in rail size, a change frm plain track t a turnut, a change f fastening systems); Pr r deficient ballast prfile; Prly cnslidated ballast; Wet and cntaminated ballast/frmatin cnditins; Generally pr ballast quality (runded, degraded, brken dwn); Pumping sleepers r ther signs f pr track supprt; Pr sleeper/fastening cnditin; Presence f fixed pints; Recent track maintenance activity; Versin 2.5 Date f last revisin: 19 Jul 13 Page 5 f 8

6 Inspectin and Assessment (xiii) Light track structure fr alignment and traffic cnditins. General inspectins shall be scheduled at an interval apprpriate t each lcatin, dependent n its nature and cnditin, and ther seasnal factrs but shuld nt exceed twelve (12) mnths r as specified therwise in an ARTC apprved Technical Maintenance Plan. General inspectins shuld be supplemented where apprpriate by detailed inspectins fr the measurement f rail stress, r rail mvement relative t creep r alignment mnuments. General inspectins shall be carried ut prir t the high temperature seasn t enable apprpriate actins t be taken (e.g. re-stressing r rail jint adjustment). General inspectins carried ut fr ther track infrastructure elements such as ballast, sleepers and fastenings shall als identify wrk that needs t be carried ut t maintain track lateral stability. Sectins f track where reduced lateral stability has been identified shall be nminated and managed as special lcatins until rectificatin r strengthening wrk can be carried ut. Detailed inspectins may be necessary fr this purpse Further Guidelines fr General Inspectins Cnsideratin is t be given as t whether the impact n the lateral stability psed at these lcatins, is due t buckling frce r buckling resistance issues. This will impact n the way the lcatin will be assessed, and hence the actins that may be recmmended as a result. Lcatins where the rail ut = rail in prcess has been undertaken and the balance f steel has been changed and must be listed as defects in the WMS and the lcatin adjusted. This wrk shall be prgrammed befre the nset f any warmer weather. Lcatins where the rail has been restressed due t track cnstructin, recnditining r re-railing etc. and still awaiting stress free temperature checks (in accrdance with ETW Stressing Plain Line CWR with Rail Suspended n Rllers and ETW Stressing & Repairing CWR), will impact n buckling frce management and shuld be scheduled fr detailed inspectin f stress free temperature. Lcatins where it has been identified that curves have pulled in r where there are indicatins that lngitudinal creep will impact n buckling frce management, shuld be scheduled fr detailed inspectin f either stress free temperature, curve alignment r creep. Lcatins where the ballast prfile is nn-cmpliant with the nminal ballast prfile dimensins specified in ARTC Track & Civil Cde f Practice Sectin 4 Ballast, will impact n buckling resistance management and shuld be scheduled fr rectificatin. Lcatins where the track has been disturbed by tamping etc. will impact n buckling resistance management and shuld be clsely mnitred r prtected by TSR until a minimum 100,000 tnes have passed ver t cnslidate it. Alternatively, the ballast shuld be cmpacted with a shulder ballast cmpactin machine. Even after cnslidatin, these lcatins are still t be mnitred during ht weather inspectins until the end f the ht weather perid. All special lcatins are t be assessed during the scheduled inspectins t determine if there are additinal cnditins present that will increase that lcatins vulnerability t instability. Attentin is t be paid t ptential lcalised initiatrs, such as: Pr rail/weld alignment arising frm incrrect crwing, rail end alignment, pr rail prfile matching, straight clsures in curves, track alignment (including gauge), and glued insulated jints; Rail surface and track gemetry defects including pr tp, twists, dipped welds, wheel burns and crrugatins, and pumping sleepers; Rail bunching at fixed pints, i.e. bridges, turnuts and level crssings; Rail bunching due t trains stpping at signals, r t changes in grade; Versin 2.5 Date f last revisin: 19 Jul 13 Page 6 f 8

7 Inspectin and Assessment Lse/failed fastening assemblies with reduced te lad, causing rail creep; and Lcal disturbances due t under-track crssings, bridges r culverts. Particular attentin must be paid t thse lcatins n curves less than 400m radius, as tight radius curves have higher buckling risk Un-scheduled Track Lateral Stability Inspectin a) Very ht weather inspectins Particular attentin shall be paid t special lcatins such as [see Nte 1]: (i) (ii) (iii) Thse nminated frm general inspectins; Thse with a histry f temperature induced track misalignments; r Where there is reduced track resistance t buckling, fr example areas where maintenance f the track may have significantly disturbed ballast cnslidatin (e.g. slewing, ballast cleaning, cnstructin). At these lcatins rail temperature shuld be treated as a defined event until rectificatin r strengthening wrk is carried ut. Ambient air temperature limits [see Nte 3] shuld be set at the rail temperature which is estimated t be the minimum requiring an unscheduled patrl inspectin t be carried ut. Standing r temprary perating restrictins may als be apprpriate fr sme track structures and cnditins at sme lcatins. Very ht weather inspectins shuld keep a lkut fr defects and cnditins including thse defined in Clause and be carried ut as near as pssible t the time f the peak temperature fr the day. Cnsideratin shuld be given t the fllwing: (A) The need fr additinal patrl inspectins n any given day prir t r fllwing the nset f the peak temperature. (B) Unscheduled very ht weather patrl inspectins n days where the frecast temperature is significantly in excess f any daily temperature recrded since the last cl seasn [see Nte 4]. (C) Ntes: Patrl inspectins may als be necessary at times f extreme lw temperatures in areas prne t pull-aparts (break -aways), curve pull-ins and mechanical jint failures. Such special lcatins shuld be treated in a similar way t buckle prne sectins f track. [1] A patrl inspectin r a general inspectin may be carried ut in respnse t a defined temperature event but it will usually be a patrl inspectin in the first instance. Sectins f track with suspected defects identified frm any patrl inspectin shuld be further inspected by a general inspectin. [2] Special lcatins may extend ver significant lengths f track particularly in the early part f the high temperature seasn. [3] The temperatures that trigger very ht weather patrl inspectins, and the special lcatins requiring them shuld be reviewed as the high temperature seasn prgresses. Fr example, cnsideratin may be given t increasing the temperature limit as the high temperature seasn prgresses. [4] It shuld be nted that ften a significant number f track kinks and buckles ccur in the earlier part f the high temperature seasn where temperatures have risen significantly but may nt have reached the expected maximum fr the seasn. Advantage shuld be taken f such situatins t help identify areas that may be mre prne t track buckling. b) General Unscheduled Inspectins These inspectins shall be carried ut t cnfirm the presence f suspected defects identified frm track patrl inspectins r in respnse t reprted track buckles, track shift r rail pull-apart defects (e.g. by drivers, train cntrllers where track circuits indicate rail Versin 2.5 Date f last revisin: 19 Jul 13 Page 7 f 8

8 Inspectin and Assessment failure, r frm ht weather patrl inspectins) t allw actins t be determined. The cnditin f the general track structure shall be determined in terms f its cntributin t the track lateral stability. Sectins f track with identified reduced lateral stability shall be recrded and managed as special lcatins until rectificatin r strengthening wrk can be carried ut. Detailed inspectins may be necessary fr this purpse. Traffic may need t be restricted until the suspected defect r failure is inspected and the necessary actins assessed Assessment and Actins Fllwing inspectins, including thse fllwing a defined event, the track shall be assessed t verify its capacity t prvide adequate lateral stability. Where it is cnsidered the track is inadequate, actins shall be determined t manage the risk. This shall ccur in particular at special lcatins prne t track lateral stability failure, where significant changes in the cnditin f the track have been identified (i.e. its ability t deal with events up t the defined event shall be assessed). Track elements and cnditins affecting lateral track stability shuld be cntrlled in accrdance with the practices described in the fllwing sectins f this dcument: Stress cntrl f rail Sectin 1 Sleepers/fastening assemblies Sectin 2 Ballast prfile Sectin 4 Track gemetry Sectin 5 Rail stress assessment and, if necessary, adjustment shuld be carried ut when ne f the fllwing ccurs: a) Track buckle r significant heat misalignment. b) Mechanical jint failure. c) Identificatin f excessive creep. Where such defects and failures are detected the peratin f trains shuld, as a minimum, be cnsistent with the guidelines fr defects detailed in ther Sectins f this Cde. Trains shuld be pilted thrugh the site where necessary, taking int accunt factrs including the fllwing: Clearances with respect t structures and ther running lines. Track supprt cnditins, in particular where the track has shifted. Track gemetry. Versin 2.5 Date f last revisin: 19 Jul 13 Page 8 f 8