Track Monitoring

1. Track Monitoring An over View On Indian Railway

2. Track Performance • Track geometry deteriorates under influence of dynamic track loads. • Track geometry deterioration - complex issue - 3 main causes • Random settlement of ballast • Lack of straightness of rails • Variations in dynamic load along the track caused by vehicles

3. Why measure track geometry? • To identify the deviations or the defects • To compare the track with other tracks and with the benchmark • To monitor the rate of deterioration for special attention and • To give timely input and prolong the life of the asset • To assess the quality of track maintenance inputs

4. How do we assess track geometry manually? • Push Trolley Inspections • Foot Plate and Brake Van Inspections • Manual Measurements • Unevenness • Alignment • Gauge • Cross Level • Versines and Super elevation on Curves • Other track elements like LC, P&C, SEJ etc.

5. Manual Measurement - Limitations • Subjective (human response dependent) • Floating Condition • No Systematic Recording • Time Consuming; Slow and tiring • Inappropriate for Modern Track Structure and mechanized Maintenance • No Continuous record of Track Geometry • Not amenable to detailed analysis

6. MECHANISED • Objective assessment • In Loaded Condition • Systematic recording and analysis of data • Fast and convenient • Continuous record of track parameters

7. Track Performance • Final output from track - accelerations various directions • It depends on • Track Geometry parameters • Vehicle Design parameters • Speed of Operation • What are we concerned with? • Track defects which are causing the undesirable accelerations

8. PARASITIC VEHICLE MOVEMENTS Yaw (Nosing) Z Bouncing Y Rolling Uneveness Shuttling X Twist X Pitching Alignment & Gauge Y Lurching Z

9. Track Monitoring • Mechanized Measurement – Systems on IR • Track Recording Cars (TRC) – TMM directorate of RDSO – Engineering Department • Oscillograph Cars Mechanical Directorate of RDSO • Oscillation Monitoring System (OMS) – Divisions or Zonal Headquaretrs

10. Basis of Track Geometry Monitoring • Peak Based • It helps in identifying isolated localized defects • It helps in isolated attentions • SD Based • It helps in identifying bad stretch • It is useful in deciding machine maintenance

11. A A B B C C D D

12. A,B,C,D Limits (old TRC/IRPWM) Note- Not more than 10 peaks (exceedences) in a Km for a particular parameter, otherwise track be down graded to next category, suffix w r t no. of peaks exceeding B category 12

13. A,B,C,D Limits (New TRC) Note- Not more than 10 peaks (exceedences) in a Km for a particular parameter, otherwise track be down graded to next category, suffix w r t no. of peaks exceeding B category

14. Track Indices PEAK BASED INDICES • A,B,C (A,B,C,D) categorisation of Track • CTR ( Rly. Bd. Letter 90/Track-III/TK/72 dt. 18.7.90) CTR=100-(ULA+URA+TA+GA+ALB+ARB) • Rev. CTR (item 840 of 66th TSC) RCTR=100-(ULB+URB+TB+GB+0.5ALB+0.5ARB)-0.25(ULA+URA+TA+GA)

15. Track Indices SD BASED INDICES • TQI; SD based ( RDSO Report no. C-223) TQI=8(U2+2T+G+A) • TGI; SD based ( Rly. Bd. Letter 94/Track-III/TK/23 dt. 25/31.08.95)

16. PEAK DISTRIBUTION (Short Chord) – A, B, C, D Cat.UNIT OF REPORTING – 1 Km B4 B2 D34 B5 B10 C17

17. ABCD categorization ..Which track is better A9 or C15? Gauge :A limit = 3 mm, B limit = 6 mm A9 C15

18. Strength of A,B,C,D categorization Easy and convenient to understand A track may be good in other parameters but bad in one parameter

19. Limitations of A,B,C,D categorization Only no. of peaks are counted in case of exceedence and their magnitudes are not considered Comparison is not possible (no single result value is available) No correlation to the Riding Quality of the track Magnitudes of all samples of the various track segments of a block (200m) are not considered Overall health of track for a parameter is not reflected. 19

20. Service tolerances - CS No 45-Para 607 IRPWM for speed 100 Kmph to 140 Kmph

21. CTR Formula • CTR=100-(ULA+URA+TA+GA+ALB+ARB) • No. of peaks exceeding “A” category are taken for Unevenness, Twist and Gauge and exceeding “B” category taken for Alignment (all on short chord).

22. Limitations of CTR Formula • The formula based on ‘A’ peaks (B in case of alignment) which are very tight & prone to variations • Index not related to riding quality • The fluctuations are not much in good track but they are more on poor track • CTR values are generally very low , causes feeling of despondency • Wide variation in CTR values (-500 to +100) • All parameters given equal weightage .

23. Standard Deviation • More value of SD for any parameter indicates more variation and less uniform track profile. • Less value of SD for any parameter indicates less variation and more uniform track profile. • Uniform track profile results in better riding quality • SD based index takes into account magnitude of each and every data of vehicle ride while peak based index indicates no. of peaks exceeding a limit without giving an idea of magnitude of various peaks • Peak based index facilitates isolated attention but deployment of machine over long stretches can not be decided.

24. TGI Formulae (RDSO report TM-11)

25. REVISED SD BASED TRACK STANDARDS • Based on RDSO’s report No.TM-109 circulated vide Railway Boards letter No.2007/Track-III/TK/7 dated 12-07-2007 • For spot exceedences based limits those given in lettr dated 30-12-96 to be continued • Priority I; Urgent maintenance and Priority II is planned maintenance

26. TGI values for typical cases Case 1 Measured SD value = SD for New Track X = 0 so Index Value = 100 x1 = 100 Case 2 Measured SD value = SD for Urgent Maintenance X = -1 so Index Value = 100/e ≈ 36 Case 3 Measured SD value = 0 X = Index Value for different parameters ranging from 147 to 272 based the presently stipulated values of SD for new track and that for urgent limits (UI = 196.54, TI = 234.82, AI = 271.83 and GI = 196.90 TGI = 240.58

27. TGI_Max

28. TGI • TGI formula has good correlation with ride index • SD values reflect general quality of track in a block of 200m and is measure of variance over mean profile for that parameter • SD values of individual parameters should also be seen; It may happen that overall TGI of a Km is 80, however TGI of a particular parameter is 40 and need attention • Peak size of individual parameter should also be seen for “spot attention”.

29. TGI …. Contd.. • TGI for individual parameters give quality rating to the measured SD values w.r.t. the SD values prescribed for newly laid track and SD values for urgent maintenance • SD values of Unevenness, Alignment, Twist and Gauge are given weightage of 2,6,1 and 1 • Variation in the TGI value will be faster for good track with changes in the SD value more than for a run-down track.

30. Features of TGI • Tool for deciding maintenance requirement; through as well as spot • Proper appreciation of maintenance effort • Good correlation with Ride Index Values • Proper range and reasonable variation in values

31. Limitations of TGI • Combination of all parameters makes it redundant for reflecting maintenance requirement for a particular type of defect • For maintenance individual index should be considered • Very high weightage to Alignment parameter and Low weightage to TWIST which is critical for safety particularly for goods stock • It gives Values over average profile (average profile may change from a block to the other block) and not over the ideally required profile • Doesn’t indicate speed restriction requirement

32. Short Chord and Long Chord

33. Short Chord and Long Chord (TM-11) The short chord is pertinent for four wheelers and bogie freight wagons The long chord is important for passenger coaches and locomotives

34. Vehicle Response - Critical Wavelength • The wavelength of track irregularity at which resonance in vehicle acceleration occurs is defined as critical wavelength • The critical wavelength of track irregularity for any vehicle at various speeds depends on the natural frequency of vehicle in vertical and lateral mode.

35. Vehicle Response  f = Input Frequency in Hz v = Speed (m/s)  = Wave Length (m) Time Period T = /v f = 1/T= v/  Response V (m/s) Response For Unit Input fn Input Frequency of Input excitation (Hz)

36. Critical Wavelengths

39. Critical Wavelength at different speed

40. Short Chord and Long Chord (TM-11) • The short chord is pertinent for four wheelers and bogie freight wagons • The long chord is important for passenger coaches and locomotives • Longer chord for unevenness and short chords for alignment and twist are taken as the same have been selected for TMS also.

41. Track Parameters • Unevenness • At Short Chord- 3.6m & At Long Chord-9.6m (For Left Rail & Right Rail) • Twist - Lower base of 3.6m & Higher base of 4.8m • Gauge --- Variation over 1673 mm(BG) • Alignment • At Short Chord- 7.2m & At Long Chord-9.6m (For Left Rail & Right Rail).

45. Old TRC 1.8 m 1.8 m * * Vertical Displacement * 3 Axle Bogie & Measuring Frame For Unevenness Measurement

46. INERTIAL PRINCIPLE OF RECORDING ACCELERATION TRANSDUCER DISPLACEMENT TRANSDUCER ŋ=H=Z+W =∫∫ Z DAMPING H SPRING TRACK IRREGULARITIES

47. MOUNTING POSITION OF TRANSDUCERS

48. y + LVDT(L)= Vert. Profile of left rail A y + LVDT(R)= Vert. Profile of right rail B INERTIAL PROFILE - VERTICAL ò ò ÿ dt² = y ( Vert. Locus of point ‘A’or ‘B’) ÿ ÿ A B LVDT(R) LVDT(L)

49. APPLICATION OF INERTIAL PRINCIPLE IN TRC Generation of Vertical Profile

50. APPLICATION OF INERTIAL PRINCIPLE IN TRC Generation of Lateral Profile