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CONCRETE SLEEPERS AND ELASTIC FASTENINGS

CONCRETE SLEEPERS AND ELASTIC FASTENINGS. R K BAJPAI, SR PROF TRACK-2. R K BAJPAI Sr Prof Track-2 IRSE 1991 EXAM BATCH Worked in SE and SEC Railways Asst. Engineer at JSG in CKP Division Divisional Engr(W) in CKP Division Senior Divional Engineer(E) in BSP Div

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CONCRETE SLEEPERS AND ELASTIC FASTENINGS

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  1. CONCRETE SLEEPERS AND ELASTIC FASTENINGS R K BAJPAI, SR PROF TRACK-2

  2. R K BAJPAI Sr Prof Track-2 • IRSE 1991 EXAM BATCH • Worked in SE and SEC Railways • Asst. Engineer at JSG in CKP Division • Divisional Engr(W) in CKP Division • Senior Divional Engineer(E) in BSP Div • Dy Chief Engr Bridge and DYCE/Track in HQ • Dy CE/CONST/BSP • Sr DEN/CO/NGP and Sr DEN/CO/BSP

  3. FASTENING UIC ORE DEFINITION FASTENINGS OR FASTENING DEVICES ARE DESIGNED AS THAT ASSEMBLY OF PARTS , ENSURING THE CONNECTION BETWEEN RAILS AND SLEEPERS OR RAIL BEARERS IN THE CASE OF TRADITIONAL TRACK LAYING SYSTEM. OR WITH SUBSTRUCTURE IN CASE THE TRACK IS LAID DIRECTLY ON THE STRUCTURES OR ON THE TUNNEL BASE.

  4. VARIOUS TYPES RAIL FREE RIGID ELASTIC FASTENING TYPES

  5. DOWNWARD FORCES UPWARD FORCES ROTATION OF SLEEPERS LATERAL FORCES LONGITUDINAL FORCES VIBRATIONS- LOW FREQUENCY DUE TO PARASITIC MOTION VERY HIGH FREQUENCY VIBRATIONS IN VERTICAL PLANE DUE TO RAIL WHEEL INTERACTION 700 TO 1200 CPS AND AMPLITUDE OF 0.1 MM TO 0.3 MM WITH ACCELRATION OF 70 TO 100 g FORCES ON TRACK

  6. ELASTIC FASTENING

  7. MECHANISM Weight of rail Source of Vibration Vibration blocked by fastening spring Rail Fastening Vibration absorbed by rubber pad GRPSleeper Wt of sleeper Vibration absorbed By stone friction & Spring action Ballast

  8. MECHANISM LOAD ENERGY ABSORBED ERC & GRP 60 % BALLAST 25% FORMATION 15%

  9. RAIL CLIP TO KEEP SUFFICIENT CONTINUOUS TOE LOAD ON THE RAIL UNDER STATIC AND DYNAMIC CONDITIONS. TO ENSURE NO SEPERATION BETWEEN RAIL AND RUBBER PAD TO ENSURE MIN. UPLIFT UNDER PERCUSSION WAVE. OBJECTIVES OF ELASTIC FASTENING

  10. DOWNWARD LOAD ON FOOT OF RAIL CAUSED BY ELASTIC FASTENING IS CALLED TOE LOAD. TOE LOAD

  11. TOE LOAD FACTORS AFFECTING TOE LOAD DUE TO MANUFACTURING TOLERANCES TOE LOAD EXERTED BY ERC DEPENDS UPON : - RELATIVE POSITIONING OF CROWN OF INSERT HOLE, - SHOULDER OF INSERT AND RAIL SEAT LEVEL.

  12. ERC

  13. ERC MK III

  14. ERC MK V

  15. TYPE OF ELASTIC FASTENING TYPE I – IN WHICH TOE LOAD IS DERIVED FROM A FRICTIONAL GRIP OR NAILING EFFECT ERS, DS 18 AND MACBETH TYPE II – IN WHICH LOAD IS OBTAINED THROUGH A SCREW HM, NABLA, VOSSLOH TYPE III – IN WHICH THE LOAD IS PREDETERMINED AT THE DESIGN STAGE PENDROL

  16. NABLA FASTENING

  17. VOSSLOH FASTENING Sleeper screw in dowel Tension clamps Guide plate Rail Pad

  18. COMPARISION BETWEEN ELASTIC FASTENING

  19. REQUIREMENT OF TOE LOAD As per LWR theory, Rail and Sleeper act as frame -- i.e. there is no relative movement How it is ensured? ERC MARK III HAS AVg TOE LOAD OF 1000 KG UNDER 13 MM. DEFLECTION. THE AV. STATIC TOE LOAD =1000x4 =4000 KG. ASSUMING 0.5 AS COEFF. OF FRICTION BETWEEN RUBBER PAD AND RAIL, THE RAIL TO SLEEPER RESISTANCE IS APPROX. 2000 KG. THIS IS > AV. SLEEPER TO BALLAST RESISTANCE ( 1000 KG.). SO THE CHANCES OF RELATIVE RAIL TO SLEEPER MOVEMENT ARE LESS.

  20. COMPARISON OF DIFFERENT TYPE OF ELASTIC FASTENING

  21. RUBBER PAD

  22. RUBBER PAD COMMON TYPE OF PADS PIMPLE TYPE PADS GROOVED TYPE PADS THICKNESS 6 MM, 10 MM

  23. RUBBER PAD FUNCTION ABSORBS SHOCKS AND DAMP OUT VIBRATIONS INCREASE FRICTIONAL RESISTANCE TO LONG. AND LATERAL MOVEMENT OF RAIL DISTRIBUTE LOAD UNIFORMLY OVER SLEEPER PROVIDE ELECTRIC INSULATION BETWEEN RAIL AND SLEEPER REDUCE NOISE LEVEL

  24. 6.2mm TH Composite GRSP

  25. 10mm th Composite GRSP

  26. RUBBER PAD FOR IMPROVING THE PERFORMANCE OF RUBBER PAD , MATERIAL SHOULD BE WITH VARYING ELASTIC PROPERTIES. SO THE TOP OF RUBBER PAD SHOULD HAVE HIGHER MODULUS OF ELASTICITY( HARDER) WHILE BOTTOM SHOULD BE OF SOFTER MATERIAL.

  27. RUBBER PAD THE TOP SURFACE OF RUBBER PAD, WHICH COMES DIRECTLY IN CONTACT WITH RAIL, EXECUTE VERY HIGH FREQUENCY 1000 Hz (LOW AMPLITUDE 0.05- 0.1 mm) VIBRATIONS. WHILE THE BOTTOM SURFACE, WHICH COMES IN CONTACT WITH SLEEPER, EXECUTE LOW FREQUENCY 20 Hz VIBRATIONS

  28. RUBBER PAD RDSO Drawing 52 kg PSC sleeper - T-3703 60 kg PSC sleeper – T -3711 60 kg PSC sleeper – T-6618 (6.2mm, composite) PSC sleeper – T-7010 (10mm, composite) Specification IRS T-47-2006 RDSO Specs for Composite GRSP

  29. RUBBER PAD TESTS HARDNESS- MIN 75 TENSILE STRENGTH ELONGATION AT BREAK COMPRESSION TEST TENSION TEST ELEC. RESISTANCE

  30. RUBBER PAD TESTS (contd..) LOAD COMPRESSION DIMENSIONAL CHECK IMPACT ATTENUATION TEST DURABILITY TEST

  31. LINER

  32. LINER

  33. LINERS DISTRIBUTION OF TOE LOAD OVER LARGER AREA ON RAIL FOOT ALLOW FLEXIBILITY FOR USE OF DIFFERENT RAIL SECTION ON THE SAME/ COMMON SLEEPER PROVIDE INSULATION(GFN Liners) BETWEEN RAIL AND INSERT

  34. LINERS REQUIREMENTS OF LINER LINER SHOULD HAVE PROPER SLOPE TO MATCH WITH RAIL FOOT SLOPE THE VERTICAL LEG OF LINER SHOULD FIT PROPERLY BETWEEN RAIL AND MCI INSERT TO MAINTAIN GAUGE IT SHOULD BE EASY TO FIX & MANUFACTURE

  35. LINERS METAL GFN – 66 (66% NYLON AND 33% GLASS) FIBER)

  36. LINERS HORIZONTAL LEG THICKNESS FOR ROUND TOE ELASTIC CLIP 6MM FOR FLAT TOE ELASTIC CLIP 8MM TOLERANCE ± 0.2 MM VERTICAL LEG THICKNESS FOR 3702,3706,3738 & 3740 5.5 MM FOR 3707 & 3741 9 MM FOR 3708 & 3742 15MM TOLERANCE + 0 TO – 0.2 MM

  37. MAINTENANCE ISSUES

  38. Application of ERC

  39. WHY GREASING? LOADED CONDITION AXLE LOAD 22 Tons FREE CONDITION FREE CONDITION TOE LOAD 850-1100Kg TOE LOAD 850-1100Kg Minimum Compressive stress Maximum Compressive stress Minimum Compressive stress

  40. WHY GREASING? Figure shows the torsional force exerted due to corrosion. Torsional Force ERC ERC CORROSION Torsional Force LINER INSERT PSC

  41. WHY GREASING? CORROSION ERC greasing not done End of function life Jamming of ERC corrosion ERC greasing done regularly Reduction of strength Loss of Toe Load End of function Life Life cycle Time

  42. MAINTENANCE PARA 1411 OF IRPWM SHOULD BE CORRECTLY DRIVEN CLIP APPLICATOR SHOULD BE USED GREASING OF ERC AND EYE OF INSERTS SHOULD BE DONE WITH GREASE TO IS: 408-1981 (SPECIFICATION FOR GREASE Grade- ‘0’ GRAPHITE) AT TIME OF INITIAL LAYING ONCE IN EVERY 2 YEARS. IN COROSSION PRONE AREA AND PLATFORM LINES - ONCE A YEAR.

  43. TESTING IN FIELD SAMPLE SIZE : 1% (ALL 4 ERCs ON 1 SLEEPER) INITIAL TESTING 4 YEARS OR PASSAGE OF 200 GMT, WHICH EVER IS EARLIER. IN CORROSION PRONE AREA, 2 YEARS OR 100 GMT, WHICH EVER IS EARLIER SUBSEQUENT TESTING 4 YRS. OR 200 GMT 2 YRS. OR 100 GMT IN CORROSION PRONE AREAS

  44. TESTING IN FIELD IF 20% OR MORE OF SAMPLE SIZE RECORDS TOE LOAD BELOW 600 Kg, BOTH FREQUENCY AND SAMPLE SIZE TO BE DOUBLED. THROUGH REPLACEMENT OF ERC IF 20% OR MORE TEST RESULTS RECORD TOE LOAD BELOW 400 Kg. CONDITION OF OTHER FASTENINGS TO BE TAKEN INTO ACCOUNT THESE ARE ONLY GUIDELINES, RAILWAY TO TAKE DECISION BASED ON LEVEL OF MAINTENANCE, TRAFFIC CONDITION ETC

  45. INSERTS TYPES MCI ( MALLEABLE CAST IRON) INSERTS CONFORMING TO GRADE PM 540 OF IS: 2640-1977. SGCI (SPHEROIDAL GRAPHITE CAST IRON) INSERTS IRS T-46 1996 MATERIAL CONFORMING TO GRADE SG 500/7 OF IS: 1865 – 1991

  46. CONCRETE SLEEPERS

  47. DESIGN CONSIDERATIONS • THE REACTION AT THE RAIL SEAT DEPENDS UPON------- • SLEEPERS SPACING • AXLE LOADS • SPEED OF TRAINS • THE STANDARD OF MAINTENANCE OF TRACK

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