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  • 1. Working Principals of Tamping Machines LINING& LEVELLING Smoothening &Design Mode By HOTAM SINGH VICE PRINCIPAL IRTMTC/ALD
  • 2. WORKING PRINCIPALS FOR TAMPING MACHINES 1. Smoothening Mode-In this mode track is ligned/levelled by the method of error reduction ratio in 4 point (error remains 1/6 approximately) and 3 point method (error remains 1/3 approximately) and track will not reach on designed specified parameters 2. Design/Precision Mode- In this mode precise track geometry data must be known before work commences.The correct track geometry data should be input at the front tower as even small error will have a cummulative effect on the slews produced by the machine.for this 3point method is mainly used.In this track is to be lined according to specified radius or versines
  • 3. TAMPING OF TRACK
  • 4. There are two ways only; • Leave everything to machine. Sit comfortably and simply watch.-Easiest thing to do. • OR • Order the machine to do the exact things you want. Some hard work is required.
  • 5. Tamping Tools Tamping Arm (Big) Squeezing Cylinder Small Tool Bolt Main Body Squeezing Cylinder BigSleeper spacing Block Tamping Unit
  • 6. Front Input Panel Of CSM
  • 7. Front Input Panel of 09-3X
  • 8. Front Input Circuit To Lining circuit Front Input PCB Versine potentiometer Slew Potentiometer General Lift Potentiometer Front Pendulum Laser & Computer To levelling Circuit
  • 9. . • Methods of working; • Auto mode, Compensation/Smoothening mode. • No measurement of track. Some error is left out after tamping. • Design/Precision Mode. • Track is measured beforehand. No error is left out after tamping. • Working Planes; • Horizontal Plane- Lining (Single Chord). • Auto mode, Compensation/Smoothening mode - 4 point (for curves). • Auto mode, Compensation/Smoothening mode - 3 point (for straight) • Design/Precision Mode. - 3 point. • Vertical Plane - Leveling (Double Chord). • Auto mode, Compensation/Smoothening mode • Design/Precision Mode.
  • 10. LINING • LINING is a process of correction of alignment in horizontal plane • Methods of lining – Manual – Mechanized
  • 11. Lining System Comparison of 4 point and 3 point Working 3 Point Method 4 Point Method •Requires Versines to be set in the machine as Target Versine by the operator. •Versine measured at measuring bogie ( H2 ) is the reference versine ,and H1 (H1=ixH2 ) is automatically set as the target Versine. •The Track Parameters are not essentially to be known prior to work. •The Track Parameters are to be known prior to commence the work. •Error Reduction ratio is 1 : 3.14 •Error Reduction ratio is 1 : 6.09 •Residual Error is more than 4 Point ( Twice of 4 point ) •Residual Error is less than 3 Point (Half of 3 point ) •This method is best suited for smoothening mode of lining for curves. •Requires precise data. Hence called as Precision Method. Best suited for Design mode of lining.
  • 12. SYSTEM OF MECHANIZED LINING • 3 POINT LINING – 3 points are used on the curve and straight • 4 POINT LINING – 4 points are used on the curve
  • 13. Why people likes Smoothening Mode (Four Point) Because • PWI becomes free in this mode of tamping, no need to furnish track profile / geometry data. • Can be resorted, when geometry is unknown. • It is easier and faster to use in the field. • The evaluation of the lining system is not according to fixed points but according to the alignment. • Due to the nature of the errors where large slew are expected. • On unstable track
  • 14. INPUTS
  • 15. Versine Potentiometer • This potentiometer is used for feeding versine and Vm value. • This potentiometer is provided in front cabin. • Toggle switch decides direction of feeding.
  • 16. Slew potentiometer • This potentiometer is used for feeding slew value(offset value). • This potentiometer is provided in front cabin.
  • 17. • R = INFINITE • HENCE H = ZERO • WHILE WORKING ON STRAIGHT ZERO VERSINE IS FEEDED
  • 18. ON TRANSITOIN • THE THEORITICAL VERSINE ON TRANSITION IS CALCULATED FOR EVERY SLEEPER AND FEEDED B D
  • 19. Lining System Versine measuring Arrangement in CSM machines 6 M 4.7 M 10.05 M A B C D A = Rear Bogie : B = Measuring Bogie : C= Lining Bogie : D = Front Bogie Tr = Versine Measuring Transducers (For other tamping machines Chord length may vary ) Tr Tr Fork Hyd Cyl
  • 20. SYSTEM OF LINING 1-Transducer measuring H1 2-Transducer measuring H2 5- Digital Potentio meter (To feed curvature adapting values 6-Slew Potentiometer 16- Chord Fixing fork REAR TIGHTENING TROLLY MEASURING TROLLY LINING TROLLY FRONT TROLLY LIFTING CUM LINING UNIT
  • 21. S3 = Chord pos. 3-point-lining S4 = Chord pos. – 4-point-lining St = Working range of tamping unit A = Rear tighteneing trolley B = Measuring trolley C = Lining trolley D = Front tightening trolley 1 = Lining transducer for measuring the lining versine "H1" 2 = Transducer for measuring the versine "H2" 3 = Zero-point-potentiometer 5 mm 5 = Digital potentiometer for manual input of the curvature-adapting values (V,F,W, respec. V,HF,HW) 6 = Adjusting potentiometer for man.input of the slewing values (lining.errors)
  • 22. • 7 = Adjusting potentiometer (TELE-pot.) for remote control input of the slewing values (TEKE-operation, LASER or remote control with • sighting device) • 8 = Selector for 3-point-system • 9 = Selector for TELE-operation 10 = Lining indicator • 11 = Total evalution of all input signals • 12 = Controlsignal for automatic lining (triggered by the signal for tamping units lowering) • 13 = Manual control of the lining system • 14 = Servo control of the hydr lining system • 15 = Indicator for the adjusting values • 16 = Chord fixing fork for 3-point-lining • 17 = GVA (Track geometry adjust. motor • 18 = TELE-Receiver – adjust. motor • 19 = Control of the follow up motor • 20 = Follow up motor • 21 = Follow up – Compensation transducer
  • 23. Functional sequene of the 4-point-method • The measuring axles (A, B, C, D) are pneumatically preloaded to the selected reference rail. The chord which is stretched between "A" and "D" represents the direction of the alignment. • Transducers are mounted on the measuring trolley "B" and lining trolley "C", which are connected to the measuring chord by means of a chord leap control and a carrier fork. • Depending on the track alignment at the contact points, the potentiometers are operated by the chord. In this way, the versines are measured as analogue electronic signals. • By means of the analogue control circuit all inputs are fed into a compound line. • The versine "H2" is adapted to the versine ratio i = (H1: H2) and the lining versine
  • 24. • "H1" is added but with the polarity reversed. If "H1" is not in the right ratio to "H2", a difference signal remains on the compound line, which represents the lining value "C". This difference is fed into the indicator "10" and into the total evaluation "11". If the lining operation commences, the servo hydraulic "14" is triggered until the track is lined to the right versine ratio. • The hydraulic control and oil supply of the lining cylinders is carried out proportional to the lining value by electrically controlled valves
  • 25. Lining: Auto, Compensation/Smoothening mode- 4Pt . 12 Versines H1 & H2 measured Versine Ratio, i = AC x CD AB x BD Lining done till H1 is i x H2 • Machine measures only one rail i.e. Datum rail and rectify it. Other rail is fixed with the sleeper, hence that is also rectified. • Four trolleys A, B, C & D provided for alignment measurement.
  • 26. 4 POINT LINING PRINCIPLE For various distances for CSM, i =10.70x10.050/6.000x14.750 i =1.21508 6.000 4.700 14.750 6.000 4.700 14.750 REAR TIGHTENING TROLLY MEASURING TROLLY LINING TROLLY FRONT TROLLY
  • 27. 4 POINT LINING METHOD DESIGNED TRACK ACTUAL/ EXISTING TRACK POST TAMPING ALLIGNMENT IF FD ≠ 0 For CSM ERROR REDUCTION RATIO, n = ADxBD/ACxBC= 20.750x14.750/10.700x4.700 =6.0859 Error in H2 Curved slewed to ideal curve
  • 28. GEOMETRICAL PRINCIPLE OF 3 - POINT SMOOTHENING LINING SYSTEM • 1 = Perfect alignment • 2 = Before lining • 3 = After lining without FD input • 4 = Lining Value • 5 = Actual position of the lining chord • 6 = Theoretical position of the lining chord • 7 = After lining with error FD input
  • 29. ERROR REDUCTION ACCORDING TO THE 4 - POINT LINING SYSTEM Ideal line = 1 Before lining = 2 After lining = 3
  • 30. 4- POINT LINING
  • 31. Lining System Versine Ratio v2 (6 + 4.7) x 10.05 2r ----- = --------------------- x -------------------- v1 2 r 6 x (4.7 + 10.05) 107.535 h = ------------ = 1.21 88.5 Versine ratio h = 1:1.21 4.7 M 10.05 M 1. The lining is done at C. 2. B is always in the Worked area (i.e) „corrected area‟ 3. So V1 is taken as reference versine. 4. V2 is maintained at V1 x 1.21 5. Predicted slew is V4 4 Point Measurement Method B C D 6 M V1 A Lining Cylinder V3 V4 V2
  • 32. FOUR POINT LINING SYSTEM • GEOMETRICAL PRINCIPLE OF 4 - POINT LINING SYSTEM: • In a circular curve, two Versines of a chord are related in a ratio, depending on the measuring point distance. This Versine ratio is independent of the radius of the circular curve and is always constant. It is also valid for a straight, which may be considered as a curve with infinite radius.
  • 33. In 4 - point lining system, the track is measured at 4 points (A, B, C & D) and Versines at two points are compared (B & C) to control the lining. The existing errors are reduced or eliminated by means of the Hydraulic Lining System .
  • 34. Existing Versine H1 = AC x CD 2R Theoretical Versine H2 = AB x BD 2R Versine Ratio i = H1 = AC x CD H2 AB x BD H1 = i x H2 Hence, lining is done at Point C until Versine H1 is in the correct ratio to H2 (H1 = i x H2) at Point B.
  • 35. Versine Ratio „i value‟ for different machines • Machine i Value • 08-UNO-DUO = 1.33 • 08-275 UNIMAT = 1.35897 • 08-275-3S = 1.62241 • MP-2000 = 1.395122 • WST = 1.3292 • 09-32 CSM = 1.2157 • 09-3X TAMPING EXPRESS = 1.507
  • 36. The points A & B always remain on the corrected track and the Versine H2 at Point B represents the measuring base. Point D always remains on the disturbed track. Lining is done at Point C. H2 and H1 are separately measured by measuring and lining bogies of the machine, respectively. H2 is fed in PCB where it is multiplied with constant i and becomes “H2 x i”.
  • 37. • Thus H2 x i and H1 are then fed in difference amplifier and if the alignment is OK both will be equal and reading on the dial will indicate zero. If alignment is not OK, the difference of the two will be indicated on the dial as well as the current will flow to lining solenoids, the alignment will be corrected till both H2 x i and H1 are equal or the ratio H1/ H2 = i, is maintained.
  • 38. • In the above figure, Points A & B are on the already lined track behind the machine. The front end of the chord, Point D is on the disturbed position with lining error FD, resulting in new Versine H2. Point C is now lined until H1 is in the correct ratio to H2. Depending on the measuring point distances (Error reduction ratio „n‟), an error remains at lining Point C, which is called Left over error or Residual error „FR‟.
  • 39. n depends on Bogie distances, which is as under for different machines • Machine n - value • 08-UNO/DUO = 6 • 08-275 UNIMAT = 6.42720 • 08-275 UNIMAT = 7.61997 • 08-32 WST = 5.7411 • 9-32 CSM = 6.27692 • 09-3X TAMPING EXPRESS = 6.47
  • 40. SUMMARY • MACHINE CORRECTS VERSINE ERROR =(THEORATICAL VERSINE – EXISTING VERSINE) • IN ABOVE FORMULA H2 IS TREATED AS THEORATICAL VALUE • H1 IS TREATED AS EXISTING VERSINE • H1 AND H2 MAY NOT BE EQUAL BUT BOTH HAVE SOME RELATION HENCE H1 IS CORRECTED w.r.t. H2 i.e I H2
  • 41. • Toggle switch is given in front cabin to decide compensation direction as under: – High radius to low radius = Toggle switch outside +ve( Entry of the curve) – Low radius to high radius = Toggle switch inside – ve(Exit of the curve) Direction of Compensation Calculation of Vm • A readymade chart is given on each machine. • Vm value may be calculated by following formula: Vm = Constant Value / Radius x Transition Length – Constant value depends on Machine length as under: • 08-UNO/DUO – 83000, CSM – 82485, UNIMAT 2S - 88333, UNIMAT 3S – 116603, WST - 84000
  • 42. FR= FD/N  N= REDUTION RATIO WHICH DEPENDS ON BOGIE DISTANCES  N= (AD X BD)/(AC X BC)  FOR 08- MACHINE AD=20M ; BD= 15M ; AC=10M & BC= 5M  N= (20 X 15)/(10 X 5 ) = 6  HENCE FR= FD/6
  • 43. VERSINE COMPENSATION VALUE (Vm) FOR VARIABLE VERSINE • The constant Versine ratio is only valid for tracks with the constant curvature e.g. circular curve, straight. But when there is change in curvature (variable Versine), the Versine ratio is adapted to the curvature by input of correction values called Versine Compensation (V) values.
  • 44. • Generally, the V values are fed manually to the Versine Potentiometer in the front tower. With the provision of GVA/ALC, V values are calculated automatically and fed in the Lining system. The cut off zero point of the Versine H1 is corrected accordingly. As an example, let us consider a case of the machine
  • 45. PRINCIPLE OF ADJUSTMENT ON TRANSITION STRAIGHT TRANSITION DIRECTION OF WORK
  • 46. ADJUSTMENTS DUE TO TRANSITION- 4 POINT LINING BEGINING OF TRANSITION TOWARDS OUTER RAIL TOWARDS INNER RAIL 20M 20M 20M 20MVM VM VM = 82485 / R * L Transition Transition
  • 47. 14.75 14.75 14.75 14.75 CALCULATION OF VERSINES ON TRANSITION FOR CIRCULAR CURVE WITH TRANSITION T2 T1 T1 T2 Machine working Direction Transition Transition CIRCLAR CURVE STRAIGHT
  • 48. `
  • 49. Lining System Compensations for the differences in radius. Compensation is must in both 3 point and 4 point in Smoothening mode and in Design mode when the Machine Enters or leaves from one Radius to another Radius. Failure of Compensations will lead to formation of “Dog-Leg” effect in the entry and exit points. P.Way Supervisors should ensure feeding of compensation by the Front Tower operator.
  • 50. 4 POINT LINING DESIGN MODE • Not on straights • On curves – Determine slews by ROC – Enter slews in the slew potentiometer – Correction in Transition curve in versine potentiometer
  • 51. NON - SUITABILITY OF 4-POINT LINING ON STRAIGHT • On Straight Track H2 is zero, the machine corrects Versine at C with respect to H2. • Hence H1= i x H2 = 1.33 x H2 = 0 (i = 1.33 for 08-UNO-DUO) • If at any Point FD = 12mm FR = FD / n = 12 / 6 = 2mm • If Point H2 is at C H1 = 1.33 X 2 = 2.66mm • As the machine moves forward, H2 will be 2.66mm and H1 becomes 1.33 x 2.66 = 3.5378 • Thus, error is accumulated and the machine makes a false curve. Hence 4-point is not suitable for straight.
  • 52. 3 POINT LINING PRINCIPLE For any circular curve H1= BC * CD/2R DIRECTION OF WORK REAR TROLLY IS FOLDED X MEASURING TROLLY IS CLAMPED TO ZERO LINING TROLLY –ONLY H1 IS MEASURED
  • 53. • The Versine H2 at Point B is not measured. The track is measured at three points. The lining Versine H1 at point C is specified according to the curvature. Lining commences until the Theoretical Versine H1 is achieved. Using the 3-point system, the chord is generally fixed at point B, which results in a reduction of the distance A-B.
  • 54. Functional sequence of the 3-point-system • The chord is fixed on the measuring trolley "B" by means of the fork "16". The measuring transducer "H2" is not in use. Only the lining versine "H1" is measured which is added to the specified THEORETICAL versine (HV, HF, HW) as lining adjusting value. • The difference between the THEORETICAL- and ACTUAL versine represents the lining value. The input of the THEORETICAL versines id carried out by the digitalpotentiometer "E" of fully automatic GVA.
  • 55. • ERROR = THEORETICAL VERSINE – EXISTING VERSINE • Error---Calculated by PCB • Theoretical Versine-----Fed Manually or by Computer • Existing Versine--------Measured by Machine through Transducers
  • 56. 3 - POINT LINING SYSTEM SMOOTHENING MODE 1= Perfect alignment 2 = Before lining 3 = After lining without FD input
  • 57. 3 POINT DESIGN LINING PRINCIPLE
  • 58. • Point B is on the already lined track behind the machine. The front end of the chord, point D is at the lining error FD. Point C is lined until H1 corresponds with the specified Theoretical Versine. Specifying the Theortical Versine, H1 shifts Point C in a position which corresponds with the required radius R. The remaining error FR = FD / n, is a result of the ratio of the measuring point distances. Proceeding with the lining, Point B is at the remaining error and influences therefore the next measurement.
  • 59. Lining System 23617.5 Target Versine v = ---------- mm r Measured Versine = v + Fc Track will be slewed to Target value v i.e vc Error left behind is by the value Fc 4.7 M 10.05 M v 3 Point Error Reduction ratio B C Fc vc E.R.Ratio Fd Fc 4.7xFd ------ = ---- Fc= -------- 14.75 4.7 14.75 Fd Fc = ------ 3.14 E.R.Ratio = 1 : 3.14 D Fd Designed Existing After work
  • 60. 23617.5 Target Versine v = ---------- mm E.R.Ratio = 1 : 3.14 r Error left behind is Fc = Fd  mm Straight Line is considered to be a curve with infinite versine For Straight line 0 mm versine is set as target versine Lining System B C D Fd = 10 mm Fc = Fd  = 3.18 mm Smoothening mode of working in 3 point
  • 61. 3 POINT LINING • Straight track - smoothening mode – H1 = 0 – Error reduces to 1/3 • Straight track in design mode – H1 = 0 – Feed slews in slew potentiometer – Error is completely eliminated
  • 62. 3 POINT LINING Curves in construction • May be used to lay designed curvature • Smoothing mode – H1 fed in VPM (based on calculated value of R) • Design mode – Feed the slews – H1 fed in VPM (based on calculated value of R)
  • 63. 3 POINT LINING Curves in O / L • Not recommended • R based on average versine calculated after ROC • H1 = 23617/R & fed • Slews from ROC in design mode
  • 64. n(3- Pt) - value for different machines • Machine n(3- Pt) - value 8-UNO/DUO = 3 08-275 UNIMAT = 3.12 08-275 UNIMAT -3S = 3.297 08-32 WST = 2.91 09-32 CSM = 3.138 9-3X TAMPING EXPRESS = 3.04
  • 65. DETERMINATION OF THEORETICAL VERSINES • Versines for circular curves are determined by the formula, H = (BC x CD) / 2R. • Versine formula for transitions and track calculation with curvature variations are more complicated. Basically all formula and other calculating aids for permanent way can be applied. The THEORETICAL Versines can also be calculated by the electronic onboard computer GVA / ALC and fed into the lining control.
  • 66. NON - SUITABILITY OF 3-POINT LINING ON CURVE IN SMOOTHENING MODE • On Cueved Track H2 is zero, the machine corrects Versine at C with respect to theoritical versine values. • As per principle of 3 point, error reduced to 1/3 but there is no comparision of curvature (versines) at two points in the pattern of 4 point to avoid formation of kinks in the track, hence track will disturbed due to non achieving the designed profile or smoothening due to non comparision of curvature at two points • Hence 3-point is not suitable for curve in smoothening mode.
  • 67. LIMITATION OF SMOOTHENING MODE LINING • Errors with longer wavelengths can only be corrected with the help of input of additional correction values. The front end of the measuring systems has to be adjusted in such a manner that it is moved along the design line of the track. • Another feature of the measuring systems which has to be taken into consideration is that the theory behind the automatic correction system is based on circular curves and straight track. Correction values have also to be put into the system, when working in transition curves in smoothing mode.
  • 68. • To calculate correction values in transitions it is necessary to know the basic curve data like radius, length and form of transition, end points and so on. If those are known the correction can be derived from tables in the machine handbooks. Neglecting the correction values in transitions causes misalignment and false curves resulting rough running. • Working in smoothing mode may result in considerable shifts of the tracks away from the design or original position. In curve with long welded track it may create lateral rail tension and the danger of track buckling. Furthermore, at higher speeds also long wave faults cause dynamic vehicle reactions. If those faults are not corrected, vehicle and track wear and faster development of geometrical faults are the result.
  • 69. WORKING OF TAMPING MACHINE IN DESIGN MODE • Maintenance of track geometry to desired parameter is very important for the safe and smooth running of trains. Track machines have facilities of measurement and rectification of track defects for achieving design geometry. 5 initial CSMs & all 3x machines are also equipped with ALC for track geometry measurement and LASER Sighting System (LSS) for lining besides other features for design tamping.
  • 70. DESIGN LINING • Modern Track Machine always corrects Versine during Alignment correction using single chord. Machine measures only one rail i.e. Datum rail and rectify it. Other rail is fixed with the sleeper, hence that is also rectified. Four trolleys are provided for alignment measurement. In design lining, only three trolleys are used.
  • 71. DESIGN LINING –3 POINT ON STRAIGHT • Curve of infinite radius- H1=0 • Find out slews on long chord (80-300 m) • Correction of kinks at joint &weld • Distribute slews on every 2nd /3rd sleeper • Run the CSM/T.EXP & feed the slews
  • 72. Lining System v = ab/2r v = (4.7 x 10.05)/2r 23617.5 Versine = ---------- mm r 4.7 M 10.05 M v Lining Cylinders v1 3 Point Measurement Method B C D V2 A The Versine (v1) is Referred with Target Versine (v) (v) is set in the machine. v – v1 = v2 The slew is v2
  • 73. • Single chord lining system is used in present generation tie tamping machines viz UNO, DUO, CSM, tamping express. Four trolleys are provided for alignment measurement. In design lining only three trolleys are used. The trolleys are pneumatically pressed against reference rail, and transducer provided on lining trolley measures offset of alignment at C (distance between lining chord and center of lining trolley). DESIGN LINING
  • 74. • After measuring the offset track is slewed so much that specified versine is achieved at lining trolley location The specified versine is zero for straight track and certain value on curved track. After lining and packing of sleeper machine moves to next tamping position. Again lining is done at that position. This process continues till machine works. • In the lining process front trolley always remains on unlined/disturbed track and trolley (M) always remains on lined track Because of mis-alignment in track at front trolley front end of the chord will be out of its correct position equal to alignment defect at that point
  • 75. • Due to incorrect position of the front end proportional alignment error will remain after lining. Alignment error at C = AF * a/(a+b), where AF = Lining offset at front trolley. • In design lining this error is eliminated by shifting front end of the chord equal to alignment defect at that point. In machine other than UT chord wire is not physically shifted but proportional electronic signals are relayed through microprocessor(Lining PCB) to lining unit and track is lined accordingly. • Total slew at C = Lining offset measured by transducer at C + Proportional signals corresponding to lining offset at front trolley – Versine to be kept at C.
  • 76. • Functions available in machine: • Values of slew, versine, unevenness and cant are fed in machine through potentiometers. Various input potentiometers of CSM machine provided in front cabin and used in design lining and leveling are lifted below: Front Cabin - • Designed Slew (FD Value) (Three Feeding options –Manual/LASER/Computer) • Designed versine value and Vm(versine companatsation value)- Two feeding options are available-manual through potentiometer and geometric value assessment (GVA computer) • General Lift- selected on the basis of crosslevel difference(+/- )longitudinal level variation • Cross level correcting potentiometer– To give extra lift up to +10 mm to base rail for correcting cross-level in addion to general lift • Working Cabin- Cant Value( CSM,CSM-3X) Cross level correcting potentiometer–extra lift provision up to +5 mm to base rail for correcting cross-level in addion to
  • 77. Practical problems in Design Tamping: • Large quantity of graph paper is required for plotting reduced level of rail top for calculating lifts. Scale used for plotting is horizontal 1 cm = 10m; vertical 1 mm = 10 mm. One meter graph paper is required for plotting one kilometer track. Least count for plotting lift is 10mm. So error less than 10 mm will not be rectified. • Choosing good point for lining is subjective and requires experience. • Measurement of slews by theodilite is on track method and survey is done in time available between two trains. In off track method also setting of instrument disturb during passing of train. • Two operators are required in front cabin for feeding values of slew, lift and versine in curves. • Curves require two three tamping because most of the time designed slew comes more than maximum limit of machine. • Some times machine is backed to rectify cross level. In that case values of feeding in front cabin is required to be changed.
  • 78. Condition for Design Lining  Design lining is applicable only for that track where summation of existing versine is equal to summation of theoretical versine.  Else Smoothening mode will be more better.  FD (offset value) to be written on alternate sleeper with direction.
  • 79. Lining: Design / Precision Mode 3-Point • In Design lining, only 3 Measuring trolleys used. • FD (Slew) values & Versines determined beforehand . • Track lined until Target/Specified Versine reached. • FD values also fed. • Left over error at C eliminated, FR = 0. FD
  • 80. • 1 = Perfect alignment • 2 = Before lining • 3 = After lining without input F D • 4 = Lining Value • 5 = Actual position of the lining chord • 6 = Theoretical position of lining chord • 7 = After lining with input of F D Geometrical Principle of 3-Point Design Lining Correction at C = Lining Value (4) = (H 1+FC) - H H- Measured V H 1- Theoretical V FC- Proportional Lining offset at C
  • 81. Determination of Lining Offset/Slew Values FD A. By Long Chord (Ann 5.3 to IRTMM): • By measuring offsets at 5m intervals on 40m chord on straight and at 10m intervals on 20m chord on curves. • But, long-wave track geometry faults with longer λ from about 70m become significant with the increase in speed. • Assuming typical natural frequency of vehicular oscillation, f as 1Hz, the critical track geometry fault λ even in speed range upto 160km/h is upward of 40 m {λ=v/f=(160x1000)/(3600x1)= 44.44m}. • On straight, the most preferable chord length for alignment correction is in the order of 60–80m. B. Theodolite Method with normal ranging rods: • For such chord length, if Theodolite with the standard tripod stand is used, it takes 10-12 minutes for centering, leveling & measurements and whenever a train approaches, Theodolite is to be removed and reset. • It is even difficult to ensure verticality of Ranging rod.
  • 82. Determination of Lining Offset/Slew Values FD C. By Theodolite using the Specially Designed Gadgets: • More practicable, fast FD measurement without repeated centering / leveling of Theodolite. These are: • Scaled Sliding Table: Made of metal L-1.85m, H-0.45m on which Theodolite slides laterally at required distance. • Target: Made of metal and zero point has a fixed vertical pointer of 0.75 m height. • Satellite: Made like the Target with a movable vertical arm of L-30cm and H-45cm in „reverse T shape‟ ┴, with a 30cm Steel scale (L.C.-1mm) at either ends at 15cm from centre point on which vertical arm slides laterally. • This movable vertical arm is sighted and brought in line with line of collimation of Theodolite and Target. • Shift of movable vertical arm from centre point is Slew. • Slew at alternate sleeper by interpolating offsets.
  • 83. • Using the Theodolite and Target, a chord of up to 400 to 500 meter or more as per ranging capacity of instrument (longer chord will give better results) may be taken between 2 Good points. • This is the line of collimation of Theodolite at a fixed lateral distance from gauge face of Reference rail. • Slew measurements at every 5m intervals are directly measured Scaled Sliding Table Target (Fixed Arm) and Satellite (Movable Arm)
  • 84. • Initial 5 CSMs (901 to 905) & all 3x machines provided with a Laser Sighting System to extend measuring system on straight. LSS is in disuse on the aforesaid 5 CSMs. • Laser lining is used on straight track in 3-point mode to remove long misalignment or false curve. • Laser system consists of a Laser gun mounted on Laser trolley and a Laser Receiver mounted on Front trolley. • Laser trolley is placed in front of the machine upto 300m. • On CSM, Receiver is adjustable. It follows the Laser beam and the position is detected by a transducer that provides an input to the lining system equivalent to FD. • On 3x, 200mm square Receiver is fixed on Front trolley. Displacement of Laser beam as it impinges on Receiver from initially set centre i.e. FD, is measured and displayed on a Micro-controller and entered into Lining system. D. Determination of FD by Laser Sighting System
  • 85. Lining System B C D V2 is maintained at V1 x 1.21 V1 = 0 so, V1 x 1.21 is also 0 Slew = 0 – measured Versine V2 = - 10 mm Fd = 0 mm Rc = Fd  = 0 mm Design mode of working in 4 point A V1 V2 Fc Fb
  • 86. FIELD MEASUREMENT FOR DESIGN LINING OFFSET BY LONG CHORD • Surveying and Marking of Slews without any Infringement to SOD: • Surveying should be done between two good points, which may be on well maintained obligatory points i.e. girder bridges, level crossings, points & crossings, permanent structure etc, with the centre line of track on the design or original theoretical position. • In case of any shift in alignment of the centre line at obligatory points from the design or original position, the centre line must be brought to design or original theoretical position, manually for a minimum track length of 50m before surveying.
  • 87. • Lining errors are to be determined by measuring offsets at every 5 m intervals on 40 m chord on straight track and at every 10 m intervals on 20 m chord on curves track and marked on the track. S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 BRIDGE Level Xing 0mm 5mm 10mm 10mm 10mm 10mm 5mm 5mm 5mm 0mm 0mm
  • 88. • The required slew at every alternate sleeper is worked out by interpolating the offsets. The slews are then marked on alternate sleepers and Design tamping done by feeding the slew values to Slew Potentiometer in the Front tower. BRIDGE Level Xing 0 1 2 3 4 5 6 7 8 9 10 ------ 10 9 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 -------- 10 9 8 7 6 5 4 3 2 1 0
  • 89. Surveying and Marking of Slews in case of Infringement to SOD • If the required slew is infringing the SOD viz OHE Mast etc, the slew has to be worked out taking note of the obligatory points and ensuring that there are no infringements to moving dimensions as below. BRIDGE LEVEL XING INFRINGING EXISTING TRACK PROPOSED TRACK OHE MAST Required Slew Values Infringing SOD
  • 90. BRIDGE LEVEL XING EXISTING TRACK FINAL SLEW OHE MAST • The final worked out slews are then marked on alternate sleepers and Design tamping done by feeding the slew values to Slew Potentiometer in the Front tower. Final Slew Values With No SOD Infringement
  • 91. Surveying Design Lining Offset By Theodolite • The long-wave track geometry faults become significant with the increase in speed of trains. • Assuming the typical natural frequency of vehicular oscillation to be 1 Hz, the critical track geometry fault wavelength even in speed range upto 160km/h is upward of 40 m. • While working on straight track, the most preferable chord length for alignment correction is in the order of 60 – 80 m.
  • 92. • For achieving such chord length, if the Theodolite with the standard tripod stand is used it takes about 10-12 minutes for centering, leveling and measurements. • In the saturated high density routes, so much time is not available and whenever a train approaches, the Theodolite is required to be removed and reset. • It is even difficult to ensure verticality of Ranging rod at target.
  • 93. • For making it more practicable, fast and efficient, some specially designed gadgets, may be developed, which makes the direct slew measurement with Theodolite quite easy. Using these gadgets, a chord of upto 400-500 metre or more as per capacity of ranging of instrument may be taken between 2 good points, which is the line of collimation of Theodolite at a fixed lateral distance from gauge face of reference rail of existing track and the slew measurements at every 5 m intervals are directly measured on specially designed Satellite with reference to the line of collimation. • The equipments and specially designed gadgets used are as follows:
  • 94. • Theodolite: Normal Theodolite • VHP Sets: One each at Theodolite, Satellite and Target i.e. total 3 Nos. • Scaled Sliding Table (SST): It may be made of wood or metal with 1.85 m Length and 0.45 m Height. On upper side, one horizontal graduated table is fixed in which a plate is mounted on which Theodolite slides laterally to keep it at any required lateral distance from the reference rail. A lug is provided similar to that provided in gauge- cum-level. Touching Hook is on left side of the sliding table stand to bypass the burr on rail. SST will be perpendicular to rail, when both lugs are touching reference rail.
  • 95. Scaled Sliding Table (SST)
  • 96. Satellite • It may be made like the Target described ahead with a movable vertical arm of length 30 cm and height 45 cm in „reverse T shape‟ ┴, painted white with a black vertical central line pointer towards Theodolite and a Satellite scale (30 cm Steel scale with Least Count – 1mm) on the upper side at either ends starting at 15 cm distance from the centre point on which the vertical arm slides laterally. During survey, this movable vertical arm is sighted and brought in line with the alignment of line of collimation of Theodolite and Target.
  • 97. • The shifting of movable vertical arm from centre point is read from Satellite scale and deviation is directly recorded as slew at that point. Alternatively, the Satellite may be prepared from existing gauge-cum-level. In middle portion of the vertical face towards Theodolite, a teethed scale made of luminous red strip is pasted for a length 20 cm either side of zero (centre) point. The height of triangular teeth is 10 mm and distance between the two apexes of teeth is 10mm. This is further divided into 5 equal parts by 4 nos. of black horizontal lines to give a least count of 1 mm.
  • 98. Target • It may be made of wood. One end of its horizontal board ensures reference rail contact and zero point has a fixed vertical pointer of 0.75 m height painted white and has got a red vertical central line passing through zero point towards Theodolite.
  • 99. Method of Working • Preliminary Works: –Marking of stations at 5 m apart at the centre of track. –Selecting good point at about 300- 400 metre apart or more as per instrument capacity. These good points should have their position in the mean alignment of the existing track.
  • 100. Slew Recording Step 1 – Check squaring of SST with reference rail by touching it‟s both the notches on gauge face. Step 2 – Set the Sliding table at zero point, place Theodolite and level it. Step 3 – Sight the Target and fix the line of collimation. Step 4 – With the alignment of line of collimation, read deviation at Satellite scale by seeing through telescope of Theodolite.
  • 101. Step 5 – Take and record deviations of subsequent stations till the readings are visible with the telescope of Theodolite. Step 6 – Leaving satellite on last recorded station, SST is shifted on second last recorded station. Step 7 – Slide SST as per slew reading of the station on which it is shifted, place Theodolite, level it at site the target again so that initial line of collimation is maintained for further measurement of slews. Repeat the steps till Slews of each stations at 5 m apart are recorded for full length. • An example on Field measurement by Theodolite is as follows.
  • 102. FIELD MEASUREMENT FOR DESIGN LINING OFFSET BY THEODOLITE • Surveying and Marking of Slews without any Infringement to SOD: • Preliminary Works and Slew Recording Steps are already given in the presentation. However, the following procedure may be followed for Permanent (Girder Bridges, Fixed Structure etc.) and Temporary Obligatory points (Level crossings etc):
  • 103. • In case of any shift in alignment of the centre line at Permanent obligatory points (Girder Bridges, Fixed Structure etc.) from the design or original theoretical position, the centre line must be brought to design or original theoretical position, manually for a minimum track length of 50m before selection of good points. • Either the Permanent obligatory points or any other points at about 400-500m apart having their position in the mean alignment of the existing track are taken as good points. Thereafter, the Working Method as already
  • 104. • Temporary Obligatory points (Level crossings etc) should be opened out and may be shifted to the extent possible after ensuring that there are no infringements to moving dimensions. • Any shifting of Temporary Obligatory points should be approved by the ADEN. BRIDGE TEMPORARY OBLIGATORTY POINT PERMANENT OBLIGATORY POINT / GOOD POINT PERMANENT OBLIGATORY POINT / GOOD POINT LEVEL CROSSING
  • 105. BRIDGE LEVEL CROSSING 0 1 2 3 4 5 6 7 8 9 10 ------ 10 9 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 -------- 10 9 8 7 6 5 4 3 2 1 0 ST0 ST1 ST2 1 2 1
  • 106. 3x Express 3x can record the Track Parameters in “Record Run” at 8 to 10 KMPH. The recorded parameters can be analysed with the “On- Board Computer” (ALC). Longitudinal surface correction values, Vertical curve values can be calculated. These values can be fed to the machine automatically while working. Curve slewing values can be calculated with this computer duly taking care of transitions on either side. These values can also be fed to machine automatically. The lift values of Datum rail and Cant rail including the Super Elevations are also fed. Design lining can also be done without “Record Runs” by calculating the slews and lift values and feeding them to the “ On- Board Computer (ALC)” manually.
  • 107. LASER SIGHTING SYSTEM • Initial 5 CSMs (from 901 to 905) and all 3x machines are provided with a LASER Sighting System (LSS) that can be used to extend the measuring system on straight track. • LASER lining is used on straight track in 3- point mode to remove long misalignment or false curve. • The LASER system consists of LASER gun (transmitter) and LASER receiver. The LASER trolley which consists of laser gun is placed in front of the machine up to 300 m away.
  • 108. • The receiver mounted on the front tightening trolley is adjustable so that it follows the LASER beam and the position is detected by a transducer that provides an input to the lining system equivalent to the offset of the front of the chord. As the machine is working it moves up to the LASER trolley until the distance is a minimum of 20 m away. LASER system operates fully automatically and is able to cope with distances of up to 300 m. But LASER lining is only applicable for straight track. Important details are as follows:
  • 109. • By means of a special device, the LASER beam is fanned vertically in such a way that, the eventual change in track height has no influence on the system. • By means of an automatic follow up control, the LASER receiver is always positioned at the centre of the LASER beam and therefore determines the input of the slewing values. • The distance of the LASER gun from the machine is also dependent on the ambient conditions (rain, snow, fog, high ambient temperature). In good ambient conditions (clear, dry air) the lining distance can be extended considerably.
  • 110. Working Sequence of Design Lining with the Laser Sighting System • Phase 1: When the design lining commences the front end of the chord with the LASER receiver is shifted by the amount of the error FD in the direction of the THEORETICAL alignment, whereby the follow up control is switched off. If the lining errors exceed certain amount, a transition is necessary for the new alignment.
  • 111. • LASER transmitter is positioned as far as possible from the machine, adjusted laterally over the amount of the lining error F, aimed at the LASER receiver and fixed in this position.
  • 112. • Phase 2 and 3: The design is set; the follow-up control is switched on. The track is lined at point C and matches exactly with the line of sight.
  • 113. • Phase 4 and 5: The machine drives forward and the front end of the chord is matched up again with the line of sight. The machine is ready for the next lining operation.
  • 114. PROPORTIONAL LEVELLING SYSTEM • The tamping machines with non-displaceable front end of the leveling chords are equipped with a proportional levelling and lifting system for measuring and correcting the track geometry. • Measuring of the Longitudinal Profile: The track is measured at three locations per rail: - At the front of the machine (location “F”) for determination of the actual level and the front measuring reference point. - In the area of the tamping units (location “M”) for the proportional control of the hydraulic track lifting system. - At the rear of the tamping units (location “R”) on the already corrected track for determination of the rear measuring reference point.
  • 115. • A chord is stretched above each rail between the reference points “F” and “R” which forms two, independent from each other, measuring references for the longitudinal level. • Measuring transducers are mounted on the feeler rod of the centre measuring device. The control arms of the transducer are connected with the leveling chord. Proportional to the level of the track at point “M”, the measuring transducers send electronic signals for the automatic control of the track lifting Servo hydraulic system.
  • 116. • Measuring of the Cross Level: • At the measuring points “F” and “M” the cross level is measured by means of pendulums. • The difference between the THEORETICAL and the measured ACTUAL cross level at the front measuring point “F” is automatically transmitted to the lifting adjustment, corresponding to the side. • During the lifting and tamping operation, the cross level is checked at the centre measuring point “M” (in the area of the tamping units).
  • 117. • The measuring of the cross level at the rear measuring point “R” (optional) serves several functions: –Checking the cross level of the track which has been lifted and tamped immediately beforehand. –Recording of the cross level by means of an electronic recorder. • Input of the Lifting Values: The adjustment of the track lifting takes place at the front reference point “F” and is automatically and in the right proportion transmitted to the cut off points of the measuring transducer mounted on the centre measuring device “M”.
  • 118. • The leveling system may be used for the following methods: –Compensating method: Without having the track surveyed, a required lifting value is selected. Existing longitudinal errors are reduced and the cross level errors are eliminated. –Precision method: The track has to be surveyed beforehand and the lifting values of Base rail are marked on the sleepers. During work the lifting values are set manually.
  • 119. • Base Rail: For carrying out attention to longitudinal profile, one rail is kept as Base or Datum Rail. Machine corrects Cross-level w.r.t. Base Rail, which should be selected as under: – On straight track in single line and middle track in multiple lines, higher/less disturbed rail is kept as Base Rail. – On straight track in double line, non-cess rail is kept as Base Rail. – On curves, inner-rail is kept as Base Rail. In Plasser Tampers, direction of Cant Selector Switch is to be always kept opposite to the Base Rail. In Russian Tamper, Base Selector Switch is provided for selecting Base Rail.
  • 120. • General Lift: The amount of lift, which is given to track while tamping to cover all undulations over the Base Rail, is called General Lift. It is decided on the magnitude of the dips/peaks generally available in the track. General Lift should always be more than the largest of dips which shall be ascertained by P.Way supervisor in advance. It is given to the Base Rail. General Lift is the algebraic difference of higher and lower point of Base rail + 5mm. At one time, General Lift value should not exceed 50 mm. If more than 50 mm lift is required it can be achieved by lifting twice. To be Lifted Existing Track 5 mm
  • 121. Importance of General Lift Errors that are more than the General Lifts will not be lifted and the peaks will be left over. Hence the track to be tamped is to be prior surveyed to find out the maximum dip in the section and the general lift is to be finalised accordingly. P. Way Supervisors shall ensure that the track is surveyed prior to TTM work and the
  • 122. Cross Level  So far we dealt with lift values on one rail. The lift values of the other rail is transferred to other rail through a pendulum circuit, taking into account of the cross level difference at that point.  The rail on which survey is made and general lift is given is called reference rail or “Datum Rail”.  The other Rail is called “Cant Rail”.
  • 123. Lifting of the Track Important Points to be noted 1. The Track can not be Lowered with Tamping Machines ! 2. The Tamping Machines are equipped with a proportional leveling System for measuring and correcting the Track Geometry !!
  • 124. Leveling System (1) R M F
  • 125. Leveling System (2) R M F
  • 126. Leveling System (3) R M F
  • 127. Leveling System (4) R M F Say Error „E‟ = 15 mm 14.75 M 4.7 M e = Error measured at Middle Feeler Rod (Error Portion )
  • 128. Error at Front Feeler Rod is 15 mm low i.e –15 mm E e -------- = ------ 14.75 4.7 E x 4.7 e = ------------ = 0.318 x E 14.75 E -15 e = -------- = -------- = -4.79 mm 3.138 3.128 That means 4.79 mm is to be lowered at Middle feeler rod Remember that the Track Can‟t be lowered !!! Providing a General Lift is the solution. Lift Value Calculation
  • 129. Leveling System (5) R M F Provide a RAMP of 1 in 1000 15 x .318 = 4.79 mm 15 mm G.lift in chord wire
  • 130. Leveling System (6) R M F Theoretical Extension of existing Track Theoretical Extension of Lifted Track General Lift of 15 mm 15 mm G.lift in chord wire
  • 131. Leveling System (7) R M F(Error Portion ) 15mm G.lift in chord wire 15mm error in Track 15 x 0.138 = 4.79 mm
  • 132. Leveling System (8) R M F(Error Portion ) 15mm G.lift in chord wire15mm error in Track Already low (Say 4.79 mm) Error read = 15- 4.79 = 10.22 mm
  • 133. Leveling System (9) R M F(Error Portion )
  • 134. Leveling System (10) (Error Portion - longer than machine length) Track After Work ( 15 mm Max Dip) Theoretical extension of lifted track (15 mm General Lift) Existing Track with Error (15 mm max dip) 10.05 M
  • 135. Cross Level (2) Zero Cross level Error Datum Rail Cant Rail General Lift on Datum Rail = 15 mm Lift Value on Cant Rail = Datum Rail Lift value + Cross level Difference i.e 15 + 0 = 15 mm 15 mm lift 15 mm lift
  • 136. Cross Level (3) Cross Level Error = 20 mm Cant side Low Datum Rail Cant Rail General Lift on Datum Rail = 15 mm Lift Value on Cant Rail = Datum Rail Lift value + Cross level Difference i.e 15 + 20 = 35 mm 15 mm lift 35 mm lift
  • 137. Cross Level (4) Cross level Error = 20 mm Datum Rail Low Datum Rail Cant Rail General Lift on Datum Rail = 15 mm Lift Value on Cant Rail = Datum Rail Lift value + Cross level Difference i.e 15 -20 = -5 mm 15 mm lift -5 mm lift Datum Rail will still be low by 5 mm after tamping. i.e 5 mm Cross Level Error will remain in the Track.
  • 138. • While giving the General Lift, ramp in of 1:1000 and also while closing the work ramp out of 1:1000 should be given to the track for smooth transition. 1 1000 1000 1 To be lifted Existing Track
  • 139. • For Curves, when the existing Super- elevation (SE) is less than equilibrium SE, General Lift will be equal to track irregularities over the Base Rail (Inner Rail + 5mm) and when the existing SE is more than equilibrium SE, General Lift will be the track irregularities in the Base Rail + max difference between existing and equilibrium SE.
  • 140. Feeding of Cant Value in Curve
  • 141. • In all tamping machines, generally there are two digital potentiometers for feeding the Cant value, one at front tower and another at working cabin except CSM in which there is only one potentiometer in working cabin. • Cant value is written by JE/P.way on the sleeper near inside rail seat of outer rail. • Total cant value should be distributed through out the transition length in such a way that it is Zero at TTP and Max. at CTP. • There is incorrect practice of feeding of Cant value wrongly in the field i.e. when tamping machine enters into the transition portion, the operator in the front cabin starts feeding cant value according to the value written on the sleeper.
  • 142. • As soon as cant value is fed in front cabin when it is at TTP, the lifting starts and cant rail is also lifted. Since, lifting is not required till measuring trolley reaches over TTP, it creates hump. So the operator of front cabin should not feed any cant value till the working cabin reaches over TTP. Thereafter, whatever value is written on the sleeper in front of the front cabin should be fed by the operator. • When front cabin reaches at CTP1, the working cabin is still in transition portion i.e. it has not reached at full cant value. The operator in the front cabin should keep on feeding the Cant value at the same rate till the working cabin reaches at CTP1. Thereafter, the operator in the front cabin should instantaneously reduce the Cant value to Max. Cant
  • 143. • Similarly when the front cabin reaches at CTP2, the cant value should be kept as Max. Cant till the working cabin reaches at CTP2, when suddenly the cant value is reduced to the value as written on the sleeper in front of the front cabin. • When the front cabin reaches at TTP2, although the cant value becomes zero at TTP2, but the cant value should be fed at the same rate by changing the direction of the toggle switch i.e. negative cant value is fed, till working cabin reaches at TTP2, when suddenly the cant value is brought to zero.
  • 144. • After leveling and packing of sleepers machine moves to next tamping position. Again leveling is done at that position. This process continues till machine works. In this leveling process front tower always remains on unleveled track and rear measuring post always remains on leveled track. Because of level defects (unevenness) in track at front trolley, front end of the chord will be out of its correct position equal to level offset at that point. Due to incorrect position of the front end of chord proportional level error will remain after leveling. Track leveled at C will have level error equal to LF* a‟/(a‟+b‟). Where LF = Level offset at front tower. • In design leveling, this error is eliminated by raising or lowering front end of the chord equal wire is not physically shifted but electronic signals are relayed through microprocessor to leveling unit and track is lifted accordingly.
  • 145. FUNCTIONAL DIAGRAM
  • 146. • LEVELLING SYSTEM • 1 = Pendulum for measuring and automatic transmission of the cross level errors on the front levelling feeler rod “F”. • 2 = Pendulum for measuring the cross level on the centre levelling feeler rod (tamping area) “M”. • 3 = Pendulum for measuring the already tamped track at the rear levelling feeler rod “R” and for controlling the theoretical level automatically. • 4 = Digital-potentiometer for manual in put of the theoretical cross level for the pendulum, at the centre measuring point “M”. • 5 = Win ALC for automatic input of the theoretical cross levels and adjusting values of transition, inclinations, changes in lifting values, etc. (additional). • 6 = Digital-potentiometer for manual input of the theoretical cross level for the pendulum, at the front measuring point “F”.
  • 147. • 7 = Regulator for the settlement compensation. • 8 = Distance measuring transmitter for the Win ALC control. • 9 = Manual input of the track lifting • 10 = Remote control input of the track lifting values by means of radio control or laser (additional). • 11 = Proportional transmitter on the centre levelling feeler rod (left and right) for measuring and automatically cut off of the track lifting. • 12 = Cross level recorder (optional). obslete • 13 = Indication of the cross level after tamping (optional). • 14 = Indication of the cross level after tamping (optional). • 15 = Indication of the lift (left or right). • 16 = Servo control of the hydraulic lifting (left and right).
  • 148. PROPORTIONAL – LEVELLING SYSTEM • The lifting, lining and tamping machines are equipped with a proportional levelling and lifting system for measuring and correcting the track geometry. • MEASURING OF THE LONGITUDINAL PROFILE • The track is measured at three locations per rail: • - At the front of the machine (location “F”) for determination of the actual level and • the front measuring reference point. • - In the area of the tamping units (location “M”) for scanning and proportional • control of the hydraulic track lifting system. • - At the rear of the tamping units (location "R") on the already corrected track for • determination of the rear measuring reference point.
  • 149. • A steel chord is stretched above each rail between the reference points “F” and “R” • which forms two, independent from each other, measuring references for the • longitudinal level. • 1.3 Measuring transducers are mounted on the feeler rod of the centre measuring • device. The control arms of the transducers are connected with the levelling chords. • The measuring transducers change their position in proportion to the level of the • track at point “M” and transmit electronic signals for the automatic control of the • track lifting hydraulic system.
  • 150. CROSS LEVEL MEASUREMENT Electronic precision pendulums measure cross level at the measuring points “F” and “M”. • The difference between THEORETICAL and measured ACTUAL cross level at the front measuring point “F” is automatically and for the required side transmitted to the lifting adjustment system. • During the lifting and tamping operation the cross level is checked at the centre measuring point “M” (in the area of the tamping units). • The measuring of the cross level at the rear measuring “R” (optional) serves several functions: • a) Checking the cross level of the track which has been lifted and tamped immediately beforehand. • b) Recording of the cross level by means of an electronic recorder. • c) Output of the difference between theoretical and actual superelevation values
  • 151. • On the standard version the values for the theoretical cross level are set manually. • If the machine is additionally equipped with “WinALC”, the values of theoretical • cross level are transmitted fully automatically INPUT OF THE LIFTING VALUES • Track lifting is set at the front reference point “F” and is automatically transmitted in the required proportion to the cut off points of the measuring transducers, mounted on the central scanning rod “M”. • The lifting values are entered only for one rail. The values for the other rail are added automatically, considering the cross level error
  • 152. Proportional Leveling System Suitable for both Compensation Method & Precision Method Steel chord between A-C over each rail forms LL Ref line. Point B lifted physically/electronically until it reaches A-C.
  • 153. • When exact/design Longitudinal Level not known. • Fixed GL over Base rail and faults compensated. • Left over Lifting error f due to F, as Front Point on uncorrected track & Rear on corrected track. • Only short wave defects up to 20m are removed. Leveling: Auto, Compensation/Smoothening mode Direction of Work Level error f = F*a/b = F/r, F = Level offset and r = Reduction Ratio = b/a
  • 154. DESIGN LEVELLING • Tamping Machine corrects the leveling error in the following two modes: – Proportional or Compensation mode- In this mode, General lift over the Base rail is generally fixed and smoothening action takes place. Longitudinal level and Cross-level are not completely corrected and the Machine leaves some error. Only short wave defects are removed. Details are given in Annexure-I. – Design or Precision mode- In this mode instead of General lift, the target heights are fed over the Base Rail to rectify 100% error. All long wave and short wave defects are fully removed. This presentation is to enrich knowledge of Design Levelling.
  • 155. • Levelling and Lifting System consists of two chord wires one for each rail, stretched tightly from Front tower (F) to Rear tower (R). Tamping machines rectify level defects in track by lifting it with reference to these levelling chords. Height Transducers are mounted on Middle feeler rods (M), which rest on track at the place where tamping is actually done and these are also lifted when the track is lifted. Both rails are controlled separately. For Cross-level / Super-elevation correction, Pendulums (P) are provided. Only CSM & 3x are designed for twist correction also.
  • 156. Schematic Diagram FMR P Chord Wire Chord Wire
  • 157. • Height transducers provided on Middle feeler rod measures the gap between its zero level and chord wire. Base rail is lifted to eliminate this gap and other rail is lifted to bring specified cant between two rails, which is kept zero in straight track and a certain value on curved track. Values of unevenness and cant are fed through potentiometers.
  • 158. • In levelling process, front tower always remains on disturbed (unlevelled) track and rear tower on levelled track. Because of level defects in track at front trolley, front end of the chord goes out of its correct position equal to level offset at that point. Due to incorrect position of the front end of chord proportional level error remains after levelling. • Thus, the leveled track at M is having Level error = LF*a/(a+b) = LF/r where LF = Level offset at front tower and r = Reduction Ratio = (a+b)/a
  • 159. Bogie Distances and Reduction Ratio for different Track machines Bogie Distance (m) UNO/ DUO UNI2S UNI3S O9CSM MP2000 09-3X RM (a) 4.04 3.32 4.85 3.90 5.10 4.56 MF (b) 9.64 8.89 10.73 8.90 9.05 10.67 RF (a+b) 13.68 12.21 15.58 12.80 14.15 15.23 Lifting Ratio (r) 3.326 3.678 3.212 3.232 2.775 3.333
  • 160. • In Design levelling, this Level error is eliminated by raising or lowering front end of the chord equal to level offset at that point. • In CSM, UNIMAT and 3x, chord wire is not physically shifted but electronic signals are relayed through microprocessor to leveling unit and track is lifted accordingly.
  • 161. DETERMINATION AND ADJUSTMENT OF LEVELLING ERRORS • Detailed guidelines on „Survey for Vertical Profile Correction, Plotting of Vertical Profile and Surfacing Operations‟ as contained in Ann 5.3 to IRTMM at stations marked at 10m interval using conventional level and staff are very time consuming because of repeated setting up (centering & leveling) of dumpy level, change in height of instrument, difficulty in taking precise reading on conventional staff and a lot of calculation work involved for interpolating the data. Hence, it cannot be used at the site immediately after taking data.
  • 162. • In view of the voluminous survey work involved, some specially designed gadgets may be developed, which not only makes the direct measurement of „Design Level Offset‟ quite easy with Theodolite kept on rail but it is also more practicable, fast, efficient and accurate. • Theodolite Stand: It is modified for easy fixing over rail head with the Theodolite at specified height (line of sight at 1.2m) to have a fixed height of instrument. No centering and levelling of the Theodolite is required for surfacing work in straight horizontal and inclined track as no turning of Theodolite is required. Only correct sighting of Target staff and parallax removal at Intermediate staff needs to be done.
  • 163. Design Lifting (1) What is to be done to Eliminate the Track Surface errors Completely ?
  • 164. Design Lifting (2) R M F(Error Portion ) 15mm G.lift in chord wire 15mm error in Track 15 x 0.138 = 4.79 mm
  • 165. Design Lifting (3) R M F(Error Portion ) 15mm G.lift in chord wire + Lift Value 15mm error in Track compensated 0 x 0.138 = 0 mm We must know the exact value of the dip here to get perfect 15 mm G.lift at Middle feeler rod.
  • 166. Design Lifting (4) R M F(Error Portion ) 15mm G.lift in chord wire 15mm error in Track compensated
  • 167. Design Lifting (5) R M F (Error Portion ) 15mm G.lift in chord wire
  • 168. 1- Diopter focusing eye-piece 2- Rough Pointer 3- Tilting Screw 4- Telescope 5- Focusing screw 6- mm graduation for height adjustment 7- Tripod 8- Air level 9- Clamping device
  • 169. • Target Staff: Height of target point on target staff is to be kept equal to the height of instrument (1.2m) from the bottom of staff. It is designed using luminous strips for clear visibility and also to ensure verticality without much effort. • Graduated Intermediate Staff: It is designed to take direct readings of lift required to be given to track, which can be transferred instantaneously. Graduation on Intermediate staff starts from height equal to height of instrument (1.2m) from the bottom of staff. It is designed using luminous strips for clear visibility and Air level is also provided to ensure verticality. No negative reading is indicated on staff, however, reading up to -25 mm can be incorporated in the staff which may some times be used to reduce general lift at isolated points.
  • 170. 1- Staff 2- Air Level 3- Graduated scale 4- Application-angle 5- Supporting Tube
  • 171. Mono-rail Clamping Arrangement for Theodolite and Levelling Staff
  • 172. Method of Working • Generally the rail, which is higher and has minimum undulation, is chosen as the Base or Datum rail for leveling. Guidelines for selection of Datum rail is contained in Para 1.0 of Ann 5.3 to IRTMM. • Survey is started from obligatory points like bridges, level crossing, points & crossings. When survey is started from other point, a level track of 15 m is prepared and rail top level is transferred on traction mast or rail post as Bench Mark (BM) for record. Survey of dips is done at Stations marked at 5 m interval on Base rail.
  • 173. • Two high point are chosen on Datum rail at required base length (80 to 300m interval within visual range). Care should be taken while choosing higher points that no intermediate point is higher than the chosen points. In case negative value appears during leveling, this indicates that the High Point has been badly chosen.
  • 174. • Height of instrument (line of sight) is fixed with respect to datum rail level. For this fixed height of instrument, the Target is sighted from Theodolite and intersection point of Target staff is fixed with respect to rail level, which is equal to height of line of sight with respect to rail level. Similarly height of zero point is fixed on Intermediate staff equal to height of line of sight with respect to rail level. • Once the line of sight is fixed as above, the intermediate staff will read zero value on each point which is on straight line joining base of target staff and base of Theodolite stand.
  • 175. • This is true for straight horizontal as well as inclined track. • In this way height of instrument is automatically deducted on each reading and readings of sags are achieved without any calculations on site instantly. • The required design level offset (lift) at every alternate sleeper is worked out by interpolating the level offsets taken at Stations marked at 5 m interval on Base rail. • In this method neither plotting nor computer calculations are required.
  • 176. STRAIGHT HORIZONTAL
  • 177. STRAIGHT INCLINED
  • 178. PRECISION METHOD WITH SIGHTING DEVICE • Instead of surveying the track beforehand for the precision method, the following systems may be used (optional equipment) COMBINED SYSTEM WITH REMOTE CONTROL AND SIGHTING DEVICE • By means of a special levelling device which is fixed to the track in front of the machine, a target board is aimed at, which is on the front levelling feeler. During work, the target board is adjusted to correct height by means of the remote control. These adjustments are added automatically to the lift setting. LASER-SYSTEM • A laser beam which is aimed at a receiver on the front end of the levelling feeler produces a parallel base for the required level of the track. During work, the receiver is automatically adjusted to the height of the laser beam and controls therefore the lifting adjustment
  • 179. Place the levelling instrument vertically to the chosen begin of the ramp "RA" and set the sight to the zero mark on the height adjusting graduation.
  • 180. Place the levelling staff vertically on the end of the ramp "RE" and inscribe the required lift on the sleeper or on the rail base. The inscriptions should be clearly in view of the machine operator
  • 181. One rail is determined as datum or reference rail. In a tangent the datum rail is normally the one which is higher, in curves it is always the inner rail (the lower one).
  • 182. Levelling is usually carried out form high point to high point, which are to be found within a maximal distance of 70 – 80 m (within visual range).
  • 183. In case negative values appear during levelling this means that the high point in question has been badly chosen. In order to obtain a good track geometry, the highest point within the track section must be again levelled out.
  • 184. Place the staff on every 5th sleeper, from "RE" to one machine length before "RA". Read the lifting value for each measuring point and inscribe it on the rail base or on the sleeper. Be careful not to change the axis of measurement during levelling.
  • 185. Leveling: Design / Precision Mode • To eliminate Longitudinal faults completely. • Front chord must be placed physically or electronically in correct Lifting Offset Value (F) measured beforehand. • Instead of General Lift, Target height fed over Base rail. • Other rail is laid in the correct XL/SE. • Precise LL produced. • Rectify 100% error. No left over error. • All long wave and short wave defects are fully removed. Direction of Work
  • 186. Determination of Leveling Offset F A. Using conventional Dumpy level & staff: –Very time consuming because of; • Repeated setting up (centering/leveling) of dumpy level. • Change in height of instrument. • Difficulty in precise reading on conventional staff . • A lot of calculation involved for data interpolation. • Cannot be used at site immediately after taking data. B. Theodolite with Specially designed gadgets: – Easy direct measurement of „Design Level Offset‟ with Theodolite kept on base rail. – More practicable, fast, efficient & accurate.
  • 187. • Theodolite Stand: • Modified for easy fixing over rail head with Theodolite at specified height (1.2m) to have a fixed height of instrument. • No centering and leveling of the Theodolite on straight horizontal and inclined track as no turning of Theodolite. • Only correct sighting of Target staff and parallax removal at Intermediate staff is done. • Target Staff: • Height of target point on target staff is to be kept equal to height of instrument (1.2m) from the bottom of staff. • Designed using luminous strips for clear visibility and also to ensure verticality without much effort. • Graduated Intermediate Staff: • Designed to take direct readings of lift. • Graduation on Intermediate staff starts from height equal to height of instrument (1.2m) from the bottom of staff. • Designed using luminous strips for clear visibility and Air level is also provided to ensure verticality. Determination of Leveling Offset F
  • 188. • Generally the rail, which is higher and has minimum undulation, is chosen as the Base rail for leveling. • Survey is started from obligatory points like bridges, level crossing, points & crossings. • When survey is started from other point, a level track of 15 m is prepared and rail top level is transferred on traction mast or rail post as Bench Mark (BM) for record. • Survey of dips is done at Stations at 5 m interval on Base rail. • Two high point are chosen on Datum rail at required base length (80 to 300m interval within visual range). • Care should be taken while choosing higher points that no intermediate point is higher than the chosen points. • In case negative value appears during leveling, this indicates that the High Point has been badly chosen. Method of Working
  • 189. • Height of instrument (HOI) fixed w.r.t. Datum rail level. • For this fixed HOI, the Target is sighted from Theodolite and intersection point of Target staff is fixed w.r.t. rail level, which is equal to height of line of sight w.r.t. rail level. • Similarly height of zero point is fixed on Intermediate staff equal to height of line of sight w.r.t. rail level. • Once the line of sight is fixed, the Intermediate staff will read zero on each point which is on straight line joining base of target staff and base of Theodolite stand. • This is true for straight horizontal as well as inclined track. • In this way height of instrument is automatically deducted on each reading and readings of sags are achieved on site instantly. • The required design level offset (lift) at every alternate sleeper is worked out by interpolating the level offsets taken at Stations marked at 5 m interval on Base rail. Method of Working