TRD Failure Analysis -Action to be taken.pptx

TRD Failure Analysis -Action to be taken

1. Failure Analysis & Action to be Taken in TRD K.Palani

2. PREAMBLE FAILURE : Is the state or condition of not meeting a desirable on intended objective. The act or process failing to return to its functional sate or continue. A difficult sudden collapse in physical.

3. TRD FAILURE: TRD failure is one of the foremost part affecting punctuality loss of Mail/Express/ Passenger trains and paralysing freight trains movement. TRD failure cause interruption to trains not only in that affected line, but also to adjacent line(s), until the faulty line is isolated. TRD failure hold up trains for many hours not only at the point of failure, but also on both sides for hundred kilometres, while there are generally no injuries to the staff or passenger, the effect on traffic are similar to those caused by derailments and collision of trains.

4. OHE failure may cause entanglement of the pantograph with the OHE. There would be excessive damage to the OHE over a distance of metres. ( ie ) until the train is brought to stop. The pantograph would also be badly damaged.

5. FAILURE ANALYSIS : Each and every TRD failure necessities thorough investigation and appropriate corrective action to be taken. The purpose of such detailed investigation is mainly to ascertain if any defective material, or design deficiencies or lack of maintenace are present so that corrective action can be taken in other locations .

6. INSULATORS CAUSE OF FAILURES: Defective material, manufacturing deficiency; Stone pelting by miscreant in vandal prone area; Flashover due to deposition of dust, cement, paint coating, bird droppings, lightning strike, crow nests, kite and its strings, other foreign materials etc ; Stay insulator came out from hook due to thread worn out;

7. Bracket insulator hanging due to split cotter pin of mast bracket came out. Section Insulator broken while train passing on cross over : ( i ) due to potential gradient (Paralleling Interrupters at SSPs and SP were kept open since RC failure) (ii) bridging of live and dead OHE at SI by pantograph of a train when one of the feeder circuit breaker tripped on transient fault, section insulator busted due to heavy standing arc.

8. Breakage of insulator(s) due to non availability of structure bond, non tripping of protective relays and incorrect polarity connection of CT/PT during commissioning /replacement; Obstructed movement of Cantilever Assembly/ Regulating Equipment; Non availability of double eye distant rod in ATD.

9. Stay arm insulator broken due concrete sleeper loaded on the material moving train hit the mast. Stay arm and bracket insulators broken due to vertical scaffold beam of a moving freight train became perpendicular and knocked down the mast. Stay arm insulator broken due to moving train coach under frame part (welded joint of ‘U’ stay pillar) hit the mast.

10. ACTION TO BE TAKEN: Testing of solid core porcelain/composite insulator for routine load @55/70% of specified value before erection. If more than 2 sheds are chipped/broken or there is any crack on the core the insulator should be replaced. The entire failure prone batches insulators should be replaced.

11. Insulators having 850mm Creepage Distance should be replaced . Core diameter of 9 tonne insulators having less than 72mm should be replaced. Use of Porcelain Section Insulator having better quality index. Use of Light Weight Section Insulator at Crossovers & Turnouts locations. Free movement of regulating equipment should be ensured.

12. Free movement of cantilever assembly about the mast bracket swivel should be ensured. Parallel Interrupters should be kept in closed condition at SSPs and SPs. Replacement of solid core insulators by composite insulators in polluted areas and vandalism prone area. Insulators in Heavily Polluted areas shall be replaced by Composite Insulators of 1600mm CD.

13. Application of metro arc silicon compound in polluted area. Cleaning of insulator with soap water . Based on pollution level, appropriate cleaning schedule shall be adopted and proper cleaning of all types of insulators should be ensured. If dust deposited on the insulators are hard to remove, insulator should be replaced. All insulators in cement polluted area should be cleaned once in 3 months.

14. Application of Silicon Grease in Polluted Area depending upon the periodicity. The insulators which have already completed the effective service of 40years, to be replaced on age-cum-condition basis and for polluted zone on condition basis. All kites, kite strings, crow nest, foreign materials from OHE shall be identified and removed on war footing before post summer pre-monsoon shower. Insulators with paint coating/Bird droppings/dust on the petticoats shall be identified and cleaned/replaced on priority & the quality of cleaning should be improved.

15. During AOH/POH, care should be taken to avoid paint falling on insulator petticoats by suitably covering the insulators. Foot patrolling lineman need to be educated to identify pollution level based on physical appearance of insulators and record the insulators which need cleaning in the foot patrolling form. This will help in cleaning the insulators within the next one week/15 days instead of waiting for the next AOH. This will avoid continuous dust accumulation & subsequent flashover during adverse weather condition. ESDD records should be helpful in deciding periodicity of cleaning/upgrading insulators.

16. Faulty km after every tripping to be identified, intensive foot patrolling at the identified km to be arranged and flashed insulator(s) should be replaced. Arrangement of barbed wires, around OHE mast, as anti-climbing device to eliminate monkey menace shall be made. It should be checked that the compensating plate is in vertical position so that the tension in contact wire and catenary wires is equal.

17. Without Double Eye Distant Rod 9tonne insulator will foul with the anti-falling rods of ATDs. All traction masts should be connected by structure bonds. Accurate functioning of protective relays should be ensured periodically. All kind of Acceptance Tests specified in RDSO specification should be carried out.

18. Handling of composite insulators: Storage:- One insulator over the other at 90° should be avoided. They should be stored in a dry, covered area with packing. The area should be free from oil or other petroleum products. Care during maintenance:- The ladder /person should not rest on the rest portion of the insulator. Staff working on the cantilever and on OHE should not damage the sheds of these insulators by standing or resting the ladder on these insulators.

19. CONDUCTORS CAUSES OF FAILURES Defective material, manufacturing deficiency; Silver brazed jointed contact wire (RDSO specification revised in 2000); Catenary wire/Contact wire/Jumper parted inside PG clamps at Jumpers; Aluminium Cross/Along track feeder and its jumper parted due to bimetallic clamp over heat.

20. Nonstandard arrangement- OOR contact wire of Tramway OHE supported by direct clamp instead of RRA/Suspension clamp; OOR contact wire cut at RRA clamp due to sharp edge instead of smooth edge (RDSO Drg revised in 1986); Poor quality/improper/wrong fitment of ending clamps; Catenary wire, Contact wire, Anti-creep wire and dropper cut due chemical pollution, rust and corrosion; Inadequate size , non availability of essential of jumpers;

21. Due to non provision of 130 sq.mm large span wire, Catenary strands cut : ( i ) where two anchor OHEs are crossing in anchor span. (ii) where triple cantilever assembly with plus stagger anchor OHE Catenary parted at suspension clamp due to foreign body, kite string etc., shorted live portion with earth; Misalignment of cut-in-insulators at IOL caused flashover and catenary wire cut when one side was under power block;

22. Contact wire parted at IOL (combination of tramway &conventional OHEs with normally open isolator) in front of stop signal; Catenary wire parted at UIOL due to binding wire provided instead of G jumper. (It has happened during CRS inspection, special drawn 120A, whereas on previous day AC light engine drawn only 40A, catenary wire with binding wire not failed); Catenary wire parted at FP IOL when train passing at IOL during BM at FP under power block and Parallel breakers at SSPs and SPs kept opened since SSPs and SPs were manned due to RC failure.

23. Catenary wire parted at FP IOL under feed extension on either side, SM fail to issue lower panto /raise panto caution order to goods loco pilot, which resulted causing flash over and snapping of catenary ; Un regulated OHE earthed portion of anchor span OHE came and contact with panto horn of moving train and flashed due to sag. Feeder tail not available( Retensioning once in two years to be done) Anticreep wire came and contact with panto horn of moving train and flashed due to sag. (ACA shifted to new mast on previous day)

24. Catenary and contact wire under aqua duct parted due to high resistance fault and touched rock cutting, relay did not acted due to out of reach of the relay. (Delta I not developed) Contact wire of tramway OHE parted due to tree branch fallen on OHE during trimming of tree branches. Isolator jumper came out: ( i ) from terminal connector due to loose connection, (ii) from terminal lug due to improper soldering;

25. Bridging of live and dead OHE at FP/IOL by pantograph of goods train when one of the feeder circuit breaker tripped on transient fault caused heavy standing arc and both catenary and contact wire snapped; ( Panto flash over relay not developed) Aluminium catenary wire parted inside catenary dropper clip, bimetallic PG clamp at overlaps.

26. ACTION TO BE TAKEN: Use of HDGC Contact Wire, manufactured from CCC Wire Rods, instead of jointed contact wires. Silver brazed joints -Check by inspection car once in three months in identified polluted areas/sections in which repeated failures have taken place. Conduct Ultrasonic/Eddy current testing and provide splice where weak joints have been identified.

27. The jointed contact wire in the “identified polluted areas” shall be replaced with joint-less contact wire drawn out of continuous cast copper wire rods at the earliest opportunity on programmed basis. If more than two strands of catenary wire found broken, catenary splice should be provided. Ensuring correct geometry of overhead wires. Erect the contact wire, at the required height and to keep it within the working range of the pantograph under all circumstances as mentioned in “Principles for Layout Plans”.

28. To prevent the foreign material/debris being thrown, from the Over Line Structure (Foot-Over-Bridge, Road-Over-Bridge) to OHE, protective screen should be provided in entire length of bridge. To avoid breaking of catenary strands under FOB/ROB, false catenary wire (contact wire in lieu of catenary wire) should be provided. To avoid breaking of catenary strands above/below at Steel Girder Bridge insulated catenary wire should be provided in place of copper catenary wire. The length of false catenary wire shall remain projected minimum 2 metres and Jumper should be provided on either side of FOB/ROB.

29. Hacksaw blade should not be used for cutting insulated catenary wire. The length of insulated cadmium copper catenary wire shall remain projected minimum 2 metres , Catenary splice to be provided for joining the insulated catenary and the conventional catenary on either side of the over line structure. To prevent parting of contact wire at IOL infront of Stop Signal, SI to be provided or IOL to be shifted , otherwise caution boards to stop the locos ahead of IOLs when the signal is at ON.

30. All kites, kite strings, crow nest, foreign materials from OHE shall be identified and removed on war footing before post summer pre-monsoon shower. Checking the condition of catenary wire inside suspension clamp shall be done by opening the clamps during AOH and also on finding flashover of insulators/earth fault between portal boom & cantilever. If c atenary strands cut inside suspension clamps are noticed, splice to be provided. Non provision of essential jumpers. i.e. ‘G’ jumper at UIOLs, Turnouts. ‘H’ jumpers at every intervals not less than 350m, ‘PH’ jumpers in anchor OHEs at station areas shall be ensured.

31. 130 sq.mm large span wire shall be provided, where crossing of anchor OHEs, triple cantilever assembly with plus stagger anchor OHE 130 sq. mm large span wire shall be provided to avoid rubbing and consequent parting of catenary wire. While replacing the catenary wire (due to 7 strands found cut) extra length of wire which was provided caused sag and the disturbance of both turnouts of the crossover OHE. Contact wire broken due to less diameter, i.e. between 5-6mm.

32. All kind of Acceptance Tests specified in RDSO specification should be carried out during procurement of materials. In order to avoid parting of catenary wire at FP IOL, PTFE type NS or Panto flash over relay should be provided;

33. JUMPERS   Cause of Failures: ‘ G’, ‘F’ jumper cut due to inadequate length; Incorrect usage of PG clamps; Insufficient cross section of jumpers; Non standard arrangement of jumpers;  

34. Action to be taken: ‘G’ jumper cross connection should be ensured. It should be ensured that the G-jumper are not provided on diverging side. Check for damage to the jumper wire strands & replace if necessary. Open out the PG clamps, check for damage to the jumper wire/ catenary wire/ contact wire.

35. Sufficient length and adequate loop of jumper wire shall be used to have flexibility, so as to prevent failure on account of repeated up and down movements and movements on account of elongation and contraction of OHE due to temperature variations. Adequate cross section to carry the normal currents and possible overloads due to shut down of adjacent lines, as well as during faults.

36. Ensure that all the cross track feeders are 150sq.mm, Drop jumpers and Isolators jumpers are 160sq.mm and PG Clamps are 1050-3 as per standard. Ensure that modified drop jumper connections are provided at cross track /along track feeder especially where bi-metallic PG clamps involved. Proper soldering of the ends.

37. Non standard Jumper at Insulated overlap : ( i ) ‘F’ jumper between Cross Over OHE and Main line OHE as against between IR & OOR OHEs. ‘F’ jumper is connected between OOR and IR catenary wires as against between OOR OHE catenary & contact wires and IR OHE catenary .  

38. DROPPER   CAUSE OF FAILURES: In span dropper cut and hanging infringing movement of pantograph. Register Arm Dropper cut.

39. ACTION TO BE TAKEN Sag in OHE conductors due to improper adjustment of OHE or Regulating Equipment; Wear of dropper loop; Coming out of droppers from dropper clips ( Catenary /Contact wire); Non availability of ‘H’ jumper at every 350m shall lead to draw current through droppers.

40. TURNOUTS CAUSE OF FAILURE: Most of the failures were happened when the train is moving from loop line to main line and after any maintenance work; Improper adjustment of turnouts during modification work; Fail to adjust turnout after replacing catenary wire/contact wire/ATD;

41. Combination of reg.OHE and Unreg.OHE at turnout; For replacing contact wire, new contact wire anchored in catenary instead of temporary anchoring; While replacing ATD of cross over OHE on one line, panto entangled on other line;

42. While attending panto entanglement at turnout location of cross over on one line, panto entangled with OHE on other line; Height of cross over contact wires were not correctly adjusted after cross over was changed from 1 in 8 ½ to 1 in 12; Improper level of contact wire.

43. ACTION TO BE TAKEN: Implantation of obligatory structure shall be not less than 3m. For best results, Track separation at obligatory structure should be between 500mm and 700mm. However 150 to 700mm is permitted due to site condition. Turnout span is 54m or less in case of overlap type turnout. Ensure that the vertical distance between register arm axis and contact plane is 300mm/250mm, steady arm with drop bracket/eye piece respectively.

44. Ensure that register arm tube is horizontal position. Ensure that electrical clearance and mechanical clearance to earthed structure /bracket insulator, register arm etc., from panto swept zone is 320mm/100mm. Stagger of contact wires at obligatory structures shall be as per SED. Horizontal separation between two contact wires at support is not less than 50mm and not more than 200mm.

45. In no circumstances the stagger of contact wire of turnout OHE should not exceed 300mm. The contact wire of turnout OHE should be 50mm above the contact wire of mainline OHE. The height difference in heights of contact wire of mainline and contact wire of turnout OHE in the entire danger zone which falls 10m towards turnout from obligatory structure. However, at 10m from obligatory structure towards turnout the vertical difference in the height of two contact wires shall not be less than 30mm.

46. Check that ‘G’ jumper provided at a distance of 5.6m from obligatory structure. Ensure that ‘G’ jumper provided with jumper of specified length and number of PG clamps. Ensure that ‘G’ jumper connections are cross connected, and located not in the diverge portion of turnout.

47. CHECKING BY TOWER WAGON: Tower Wagon running on Main line: Ensure that pantograph is not touching the turnout OHE. Tower wagon running on Turnout tack towards Main line: Ensure that pantograph takes up the contact wire of main line OHE smoothly at a point 650 to 720 mm from its centre line. Tower wagon running from Main line track to Turnout track: Ensure that pantograph glides smoothly from main line OHE to turnout OHE.

48. REGULATING EQUIPMENTS CAUSE OF FAILURES: Clevis and Eye ( Aluminum Bronze) broken due to 80% old flaw on the upper eye of clevis in 3 pulley type regulating equipment and OHE came down. SS wire rope, ending clamps failed.

49. ACTION TO BE TAKEN: Hex Pipe of suitable length shall be provided. Antifalling Rods shall be attached to mast to prevent falling of OHE in case of breakage of Clevis and Eye. Damaged SS Rope shall be replaced immediately. Groove radius of the pulley of ATD shall be checked during POH & Pulley with improper groove shall be changed.

50. Auto Tensioning Device shall be properly aligned. Defective component of the Auto Tensioning Device shall be replaced. Stainless Steel Wire Rope End Fitting shall be free from sharp edges. Forged steel Clevis and Eye shall be used. Washers must be provided between Clevis and Mast Anchor fitting.

51. Check the leaning of mast which ultimate lead to misalignment of OHE. Ensure that balance weights &Guide tube are intact. Ensure that double eye distance rod has been provided. Bearing shall be replaced in every POH. Force required moving the counter weight is not more than 10kg. Replacement/Rehabilitation of Auto Tensioning Device after completion of Codal Life of 30 years or on condition basis for Polluted Zone.

52. FITTINGS AND SPLICES CAUSE OF FAILURES: Improper erection of ending clamps; 130 sq.mm large span wire coming off from the ending cone; Improper bending of contact wire inside the ending clamp; Contact wire came out from splice.  

53. ACTION TO BE TAKEN ENDING CLAMPS For 130sq.mm large span wire ending clamp ( i ) incorrect part was used (i.e. joint cone R.I. No. 1104 was used instead of R.I.No . 1143); (ii) as per RDSO Drg , 2-3 mm projection beyond socket and cone shall be maintained; (iii) correct fitment of the ending clamps as per RDSO Drg shall be ensured duly taking photograph for permanent record. Catenary/Contact/ Steel wire ending clamp edges broken due to 16mm dia bolt and nut used instead of 20mm dia snap head pin.

54. Replace the fitting once in nine years (alternate POH) and carry out the necessary adjustments. The released fitting will not be reused. At least one ending clamp for both Contact wire and Catenary wire in every 10 km and check the condition to assess the attention to be given to the remaining fittings in the section.

55. In polluted areas, apart from releasing & checking one end fitting as above, every other ending clamps should be checked. Instructions for provision of contact wire ending clamps and correct method of Bending contact wire has been reiterated along with RDSO drawing. All kind of Acceptance Tests specified in RDSO specification should be stringent strictly carried out.

56. ACTION TO BE TAKEN RAISED REGISTER ARM CLAMP Open the RRA clamp; Checks the cracks/damages to the contact wire and sharp edges/ defect in the clamp fitting with the help of ‘ magnifying glass’; Check for deformation of RRA clamp; The Chamfered edges RRA Clamps shall be used to prevent the damage of contact wire.

57. ACTION TO BE TAKEN CONTACT WIRE SPLICE After splicing arrange to file the underside of the new contact wire in order to have same level with old contact wire to avoid hitting of pantograph. The fitting shall be carefully examined for cracks, other casting defects and abnormalities. If cracks, defects found the fitting shall be replaced immediately. Check to see if any slipping of the ends of two contact wires has taken place. When viewed from top window, there should be no gap between the two ends. If gap is found it shall be rectified.

58. Tightness of stainless steel studs shall be checked. Replace the contact wire splice once in nine years (alternate POH) with the new splice. Tightening with a torque wrench. No leverage shall be used. Note : Released splices shall not be reused

59. ACTION TO BE TAKEN PARALLEL GROOVED (PG) CLAMPS: Check the PG clamps for any corrosion/over heating/sharp edges etc. and take corrective action. PG Clamps must be opened, cleaned and tightness checking by torque wrench during AOH. Parallel Grooved (PG) Clamps of Droppers and Stiffeners shall be tightened. The Bolts of Parallel Grooved (PG) Clamps must be checked up thoroughly for looseness and must be tightened by means of torque wrenches with predetermined force.

60. The Chamfered edges PG Clamps shall be used to prevent the cutting of strands. The clamps shall be checked for signs of overheating and proper tightness. Instructions issued to divisions to check the PG clamps and other joints on OHE using thermal imager once in 6 months during load condition /night time. All the 8 PG Clamps at the G jumper location shall be replaced, during POH. The released PG clamps may, however, be reused in service if they can be restored to good condition after cleaning.

61. SECTION INSULATOR ASSEMBLY CAUSES OF FAILURES: Excess wear on runner, anchor clamps; Improper level of runners; Bolt and nut used instead of snap head pin; Not erected as per design; Abandoned section insulators not removed; Contact wire ending clamp pullout.

62. ACTION TO BE TAKEN: The fitting shall be carefully visually examined for cracks, other casting defects and abnormalities. If cracks, defects found the fitting shall be replaced immediately. Check to see if any slipping of the ends of two contact wires has taken place. If slipping has taken place the contact wire shall be set right after releasing the load on SI assembly. Replace the contact wire end clamps once in nine years (alternate POH) with the new end clamps. Released ending clamps shall not be reused.

63. Runners shall be checked for flash marks, hit marks and proper adjustment. Excessive contact wire wear near anchor clamps shall be checked. Level of Section Insulator assembly shall be checked and adjusted, if necessary. PG Clamps of Droppers and stiffeners shall be tightened.

64. Adjustment of Section Insulator Assembly shall be correct not only in respect of the run of conductors and jumper connections, but also the height of Contact Wire. Pantograph shall pass underneath the Section Insulator smoothly. Check with sprit level that the runners of SI are in the same horizontal plane. Check that the panto passage under SI is smooth and runners are not hit by panto pan .

65. Measure the track separation, it should be equal to or more than 1.65m if the SI is erected with the free ends of the runners towards the centre of the turnout and equal to or more than 1.45m if the SI is erected with free ends of the runners away from the centre of the turnout. Measure the stagger at SI, it should be within 100mm. Measure the sag of SI, it should be zero. Check for all the components/parts of SI and replace the defective parts.

66. CANTILEVER ASSEMBLY CAUSES OF FAILURE: Parting of Register Arm Hook Steady Arm Hook broken/ pullout Register Arm Eye Piece broken/pullout Catenary Suspension Bracket Eye broken Parting of Register Arm Dropper Register Arm Tube slipped from RT Hook Swivel clip pullout

67. The Cantilever Assemblies which have already completed the effective service of 40years, to be replaced on age-cum-condition basis and for polluted zone on condition basis. To improve the reliability of OHE, Components / Fittings used in the cantilever assembly have since being developed with “Forged Steel”. (Register Arm Hook, 25mm Drop Bracket Assembly, Steady Arm Hook (BFB), Tubular Stay Sleeve, Register Arm Eye piece,25mm Steady Arm Clamp) Cantilever Assembly Fittings and Galvanised Tubes shall be checked for rust &chipping off galvanisation. If it is found it should be replaced.

68. Register Arm/Steady Arm Hook, Register Arm Eye piece and other fitting shall be examined for cracks. At least one complete Cantilever Assembly per 10Tkm shall be removed and taken to the workshop for dismantling and detailed examination of various components after thorough cleaning. Swivelling action of Bracket shall be checked with reference to the axis of the mast. Register arm of the bracket assembly should be in horizontal position.

69. Register arm of the bracket assembly should be in horizontal position. The Register Arm and Steady Arm shall as far as possible, be in the same vertical plane as the bracket. Vertical distance between register arm axis and contact wire (Dip) should be 300mm. All cantilevers should be checked to ensure that RT is not at natural stagger and taking load. Steady arm by design always in tensile load. Additional RT dropper to be provided near RT Hook at all + RT locations.

70. Cantilever Assembly shall be adjusted strictly in accordance with the approved “Structure Erection Drawing” (SED) All Nuts shall be tightened. Locking plates shall be provided with Split Pins or Check Nuts. Stagger of IR & OOR OHE was not maintained as per SED, Hence RT not taking load and for every movement of panto the RT eye hit with RT hook, causing formation of groove which resulted in RT came out. Repeated failure at same location within five year. Exact cause revealed after second failure.

71. LEANING MAST Leaning away from track: It may take the contact wire outside the zone of pantograph resulting in pantograph entanglement. Leaning towards the track: It may infringe the moving dimensions and be hit by the trains. Reason for leaning: On embankments due to erosion of earthwork. Inadequate design of foundation. Poor execution of work.

72. Action to be taken: Leaning mast locations should be inspected once in 3 months, stagger and implantation should to be checked and corrected. Masts which are out-of-plumb in excess of 5cm can be set right. Especially masts erected with standard implantation of 2.50m prior to Nov 2010 should be prudently monitored.

73. LIGHTNING ARRESTER All codal life completed LAs replaced in MAS and SA divisions. All lightning arresters shall be provided with discharge counters and disconnectors. Instructions issued to provide metal cover on top of LA to avoid moisture entry. Minimum insulation resistance of 1000 Meg Ohm shall be maintained.

74. ANCHOR LOOP/BOLT CAUSES OF FAILURE: ATD anchor ‘J’ bolt came out from foundation due to Engineering branch while carrying out construction of drainage by JCB hit & damaged the foundation and not advised. ATD Guy rod Anchor Loop broken due to improper workmanship during casting of anchor muffing by RE organization.

75. ACTION TAKEN: Continuous tension in guy rod along with loose soil around foundation increased the crack resulting in anchor bolt coming out from the foundation. Instructions were reiterated to Engineering Department to take adequate precautions while carrying out earth work near OHE foundations. Foot patrolling LM also issued detailed instructions to see any foundation crack/loose soil especially during monsoon season at such locations where soil is excavated.

76. During joint observation out of five locations checked after breaking anchor muffing one location found anchor loop rusted and bent, advised RE to rectify. Advised CORE/RVNL/CN to ensure that anchor loops are casted as per RDSO Drg , to be checked by inspecting officials during erection of new OHE.

77. TREE FALLEN CAUSE OF FAILURE: When a tree fallen on OHE, diesel train already on run in section entangled with fallen trees and caused severe damages to OHE. Due to tree fallen on OHE and wires cut, FCB tripped, diesel train was in faulty section during fault isolation. Division was advised to counsel TPC for better coordination with Section Controllers in stopping all trains (including diesel in mid-section) when OHE is found faulty in a section.

78. For streamlining the procedure for cutting/trimming of trees to minimize the incidences of traffic disruptions due to falling of trees/branches on track/OHE, a JPO No.01/2015 approved by CEE & PCE duly signed by CEDE & CTE has been issued on 21.08.2015. As per JPO, Joint survey to be done by ADEE level before monsoon.

79. POWER LINE CROSSING CONDUCTOR CAUSE OF FAILURE: Power line crossing conductor (s) and its earth wire snapped and fallen on OHE causing parting of catenary wire, contact wire. Power line crossing conductor came down and rubbed with catenary wire since tower collapsed due to poor design. ACTION TO BE TAKEN: Power line crossings to be annually inspected jointly with EB officials and defects noticed to be recorded and compliance ensured.

80. RELAYS CAUSE OF FAILURE: Defective feeder protection module; Wrong polarity / ratio connections of CT and PT; while conducting confirmation test stay and bracket insulators were failed broken due to wrong Polarity connection in CT; Feeder relay did not acted during fault due to DC low voltage.

81. ACTION TO BE TAKEN: Performance of the protective system and relays depend upon: Correct relay setting Correct inputs (CT,PT) System earthing & bonding. Loose/missing rail bonds, high earth resistance at structures increase earth fault current path impedance thereby reducing relay sensitivities. Long term storage of equipments in unenergised state would loss of life of the equipment.

82. Control and Relay panel should not be kept in open area. In case Control and Relay panel have been stored in unenergised state for more than one year, the relays to be recalibrated by the manufacturer. Control and Relay panel should be energized once in four months for at least three hours if it is kept unenergised condition .

83. Before put in to service all the relays to be tested in the presence of OEM representative. Long term store in unenrgised condition usually spans over the warranty period and deprives railway of not only useful life, but also railways inherit a weakened product which is not covered by warranty. Setting of each relay to be done in line with RDSO guidelines .

84. FCB TRIPPING AT TSS D uring any transient tripping, specific km check to be done through SM/TXR/LC gateman etc., for any abnormality in addition to arranging foot patrolling at faulty km. Fault isolation shall be done as per control card. Numerical Relay shall be provided. If any CB trips without any relay indication, arrange to isolate the CB instead of closing again and again. FCB trips 30-40 times in a day due to non availability of 2 nd harmonic restraining features.

85. TRANSFORMER LV CB TRIPPING AT TSS TPC failed to close LV/CB after IDMTL tripping. Extended adjacent TSS supply resulting in two interruptions. TPC gave regulation message just before overload tripping. During loaded condition, two transformers may be put in service where ever PTFE NS is available at FP. Advised divisions to provide Numerical Control and Relay Panel. TPC to ensure goods train regulation in graded section in time during overload/110kV supply failure.

86. TRANSFORMER INTER TRIP AT TSS Whenever feeder CB trips with a fault near to TSS, transformer inter trip with HV OCR (Inst) relay. Improper relay setting, relay setting shall be as per RDSO guidelines.

87. INTERRUPTERS BHEL interrupters are failing due to low IR value. BMs are provided with anabond sealing at cement portion and failure arrested after checking IR values, replaced 6 low IR value BMs. Leakage current is measured by a locally manufactured leakage current monitoring kit by modifying the BDV test kit. Other divisions also use such kits to avoid line failure.

88. Interrupters got opened automatically due to malfunctioning of RTU of the SCADA system. Interrupters got opened automatically due to failure of +5V power supply unit of INTELLIN -30 RC equipment. Due to low voltage in battery. Due to leakage of SF6 gas.

89. During fault isolation interrupter could not be closed again since the HRC fuse for the spring charging motor has blown out. 110kv CB opened automatically due to tripping coil control plunger trouble. CBs, BMs at TSS got opened due to 110VDC supply failed on account of failure of two battery cells.(One was defective, other was open circuit)

90. BM outgoing side bus bar connector bolts, nuts melted and cut due to failure of bimetallic strip between bus bar terminal connector and terminal pad of isolator and loose connection.   Following instructions are issued. Quarterly checking of all connectors by thermal imaging system during loaded condition to be done. Thermal images to be captured and verified by ADEE/DEE/Sr.DEE level for any abnormality.

91. During annual maintenance, tightness of bolts and nuts of the connectors and condition of bimetallic strip are to be checked. Proper records for each connector to be maintained at depot and date of checking & action taken should be recorded. Wherever fault could not be established initially, TPCs should direct staff simultaneously for checking OHE and to the concerned switching station for identifying any PSI equipment fault. They can be used for manual operation of equipment when SCADA/TPC communication failed. TPC & field staff should be counselled suitably.

92. AT POWER SUPPLY FAILURE UP & DN ATs drop out fuse blown out due to lightning and no EB supply. In CLS panel outgoing side MCB failed and not extending AT supply neutral to signal load. MCB trips on CLS panel at station. In CLS panel neutral link burnt. All ATs additional arcing horns to be provided. LA to be provided wherever frequent D.O failures during lightning. S&T branch to provide IPS for back up during AT supply failure. JPO for ATCLS panel to be issued and SM/Gateman to be counselled for the panel operation. TPC to check availability of both up and down AT supply and working condition of ATCLS panels at all stations in morning every day. Identify and rectify the loose connections.

93. STRUCTURE BOND Due to non availability of structure bond during earth fault: Insulator(s) busted; Passengers on platform near portal got electric shock; Foundation cracked TTC mast fallen on OHE; Due to BT RC to rail connection: K series mast lacing plates melted; Ballast got melted become solid along with rail .

94. BOND SHORTED SIGNAL RAIL Structure/ cross bond shorted signal rail due to insulation sleeve disturbed during Track machines work.  TRD staff has failed to ensure the correctness of insulation sleeve on the structure bond after the completion of Engg . work. Insulation sleeve should be minimum 150mm to 200 mm below the rail where it is crossing the signal rail. Further, the sleeve should be 350 mm length. All field staff to ensure the correctness of insulation sleeve under signal rail before the completion of all types of Engg . works involving traction bonds. Further it should be checked during foot patrolling, foot inspection and joint inspection with S&T for its correct position under signal rail.

95. BOND SHORTED SIGNAL RAIL Spark noticed at glued joint during train passing Polarity bond got cut due to tie-tampering machine worked in the section. Signal failure due to Polarity bond got heavily rusted and cut inside the insulation sleeve near the point where it is crossing the signal rail in single line single rail track circuited section. Divisions were advised to check the availability of bonds (rail-bonds, polarity bonds with sleeves, earth pipes at every 100 m applicable as per Bonding code. Signal failure due to polarity bond wrongly connected Staff counselled and sent for training.

96. 4 W TOWER WAGON FAILURE Cause of Failure: 24V battery charger switch charred and self starter motor burnt. Engine water switch wire got earthed under the frame inside the cable trough. Fuel pump electrical circuit +24V supply feeding cable got melted. Electrical short circuit in water temperature switch.

97. Engine control rod bearing broken. Pneumatic PVC pipe connected came out resulted in dropping of air pressure. Rocker arm rollers dislocated and the piston stroke of brake cylinder was 70 mm instead of 32 mm. Brass bush on the steel pipe at the compressor end broken and missing and brake jammed.

98. 8 W TOWER WAGON FAILURE Cause of Failure: 8W TW Diesel pipe line blocked. Loco control circuit failed. Air lock on fuel pipe line.

99. Action to be taken: Issued trouble shooting chart for all types of Tower wagons. Check the condition of PVC pipe lines. Follow scheduled maintenance as per SMI /OEM guidelines.

100. One round of check on all TW checked and found no abnormality. Divisions were instructed to advise C & W staff to take more care while carrying out monthly inspection. Sudden material failure of brash bush. Special drive ordered to check brass bush and found OK in all 18 TW.

101. 110kV Grid Power Supply Failure Close co-ordination with SEBs for ensuring uninterrupted power supply for traction. TPCs to be counseled suitably regarding load management during 110 kV failures for regulating goods trains to avoid overload tripping / low voltage problem especially in graded section.

102. Availability of 110 kV Standby feeder from different sources shall be ensured. Restrictive Relay settings to be revised at critical feeders to utilize 100 % of the contracted demand. To improve the reliability of grid supply, this was highlighted to SRPC.

103. While cancelling power block in single line section, TPC unable to close BM due to closing latch struck up TPC failed to extend supply from adjacent TSS and issue lower and raise panto caution being single line section. TPCs to be counseled.

104. PGT- 3T Tirfor hook broken while carrying out ATD work. Come alog clamp slipped catenary wire parted, bracket insulators (2nos), anchor insulator broken. Come along slip during ATD POH. Single pulley hook broken during POH of ATD Material failure. Instructions were reiterated to test the loading appliances once 6 months as per ACTM and specifications.

105. Single pole isolator with earthing heel wrongly operated instead of double pole isolator for ballast siding. Interlocks between isolators were not been provided. No power supply to train in common loop due to miscreant opened the isolator by damaging padlock. Integral lock and Interlocks were not been provided. WPC relays acted while train passing through Neutral Section. (IOL type NS) opened the isolator by damaging padlock. Integral lock has not been provided.

106. AML’s 12 Points Action Plan S.L Special drive &Inspection on OHE 1 A drive to check turnouts/crossover OHE for its proper adjustments/alignment 2 Live line checking of Main line OHE by TW 3A Free movement of cantilever 3B Status of Overhauls ATD and its free movement 4 Checking of PG Clamps, Splices by Thermo Vision Camera. (PSI/3months, OHE/6months. 5 Provision of missing Structure bonds/Rail bonds 6 Cleaning of Insulators at finalized intervals

107. AML’s 12 Points Action Plan S.L Special drive &Inspection on OHE 7 Checking and calibration of protective relay at specified intervals. 8 Attention to Critical implantation (<2.36m +curve allowance) mast on main line 9 Replacement of rusted Cantilever Assemblies 10 To check the healthiness of lightning Arresters in lightning prone area 11 Replacement of silver brazing joints in contact wire 12 Provision of screens of to 1.83m height on all FOBs to cover gaps

108. CONCLUSION Division should ensure the presence of TRD supervisor during any modification work in existing OHE is carried out by RE/RVNL/CN. To upkeep the Overhead Equipment and to get the uninterrupted services of Electric Traction, it is essential to introduce regular laid down definite Maintenance Practice/renewal, through regular Works Programme. It is observed that majority of these failures could have been avoided, had the Railways had taken preventive steps in time and strictly followed the Special Maintenance Instruction (SMIs) & Instructions (Ins) issued by RDSO.

109. Replacement of equipments and components after completion of its Codal life in normal zone. Replacement of equipments and components on condition basis in polluted zone.

110. “Human performance is highly reliable and dependable once a job is learnt.” Hence, Railways shall train the maintenance staff about important parameters of OHE and guide them how to carry out maintenance of OHE as per Special Maintenance Instruction (SMIs) & Instructions (INs) issued time to time by RDSO. “The future failures defends on what you do preventive measures today.”

111. A little neglect may breed mischief. Dr. Thomas Fuller A Kingdom was lost, for want of a Nail. Un Known A stitch in time saves nine. Mark Twain Failure will not appear until a unit has passed final Inspection. - Arthur Bloch

112. Thank You