LEVELLING Master Copy for IRTMTCALD by IRICEN LEVELLING

LEVELLING Master Copy for IRTMTC/ALD by IRICEN

LEVELLING OF TRACK BY TAMPING MACHINES

LEVELLING - Principle • Longitudinal level of track is corrected by Proportional LEVELLING • On the basis of two reference level, level of other point in between may be found and corrected. A B • In Tamping Machine a chord is stretched between Front & Rear Tower on both sides which becomes the reference level.

LEVELLING SYSTEM Rear Tower Middle Feeler Rod Chord wire Front Tower WORKING DIRECTION R M F • Tamping Machine can only Lift and Slew the track. It cannot Lower the Track. • One of the rails is selected as Datum / Reference rail. • Machine corrects the level of one pre-selected rail (i. e. Datum / Reference rail) and maintains Cross-level on other rail with reference to datum rail.

LEVELLING SYSTEM RHS HT LHS chord

LEVELLING SYSTEM F Height Transducer M Front Pendulum: • For automatic cross level correction or to maintain fed SE. Middle Pendulum: R • For indication only. Rear Pendulum: • For twist correction, recording purpose. Height Transducer: F – Front Measuring Tower M – Middle Feeler Rod (Measuring & correcting point) R – Rear Measuring Tower • For measuring & correctinglongitudinal level.

Longitudinal level correction • Position of these three points (R, M & F) decides the displacement (angular movement) of the movable arm of height transducer (M) which is attached with the pneumatically stretched leveling chord between front and rear tower at ‘M’. • Depending upon the field condition, position of these three points varies.

Longitudinal level correction • If the movement of the movable arm of height transducer • is positive (in upward direction) - lifting & tamping of track at ‘M’ will be done by machine. • is zero - no lifting at ‘M’ shall be required and hence only tamping will be done • is negative (in downward direction) – Lowering of track will require But since machine can only lift the track and cannot lower the track, and hence only tamping will be done

Longitudinal level correction • Depending upon the condition of track there are various situation arises in field. Machine act as per the instructions issued through PCB. • Action taken by machine depends upon the position of rear tower, front tower and middle feeler rod on the track. • Since the position of rear tower is behind the tamping unit and is already attended, it is assumed that it is on correct leveled track. • Position of middle feeler rod is at the location of tamping unit which is to be corrected and tamped (may or may not be on correct level track) and • front tower is at the location where track has not been attended i. e. on unattended track which may or may not be on correct level track.

Longitudinal level correction – Position of Middle Feeler Rod (M) and Front Tower (F) in various situation in field

Longitudinal and Cross Level Correction System • Datum Rail level is corrected first. • Height transducers provided on Middle feeler rod of datum rail measures the gap between its zero level and chord wire and lift the datum rail to eliminate this gap. • Other rail (Cant rail) is lifted to bring specified cant between two rails, which is kept zero in straight track and equal to super elevation value on curved track. • Specified cant = zero (straight track) = Super elevation (curved track)

Longitudinal and Cross Level Correction System - LEVELLED Track NO LIFTING ONLY PACKING Height Transducers Measuring Point is Touching Chord Pendulum through PCB R R F M M WORKING DIRECTION Lifting Cum Lining Unit (LIFT=0) F Cant Rail Datum Rail

Longitudinal and Cross Level Correction System - Dip at M Rail lifting till displacement = 0 degree R LIFTING at M AND PACKING M Height Transducer Positive displacement F CANT RAIL R Lifting Cum Lining Unit F DATUM RAIL Sag Corrected M WORKING DIRECTION

Longitudinal and Cross Level Correction System - HUMP at M Height Transducer Negative displacement HUMP REMAIN at M ONLY PACKING M F CANT RAIL R Lifting Cum Lining Unit R M F WORKING DIRECTION DATUM RAIL

Longitudinal and Cross Level Correction System –Hump at F Height Transducers X Pendulum through PCB Height Transducer Positive displacement R M Final Level X Cant Rail M R F Lifting Cum Lining Unit F Lifting Machine Working Direction Datum Rail

Longitudinal and Cross Level Correction System – DIP at F NO ACTION ONLY PACKING Height Transducers Height Transducer Negative displacement TILTED CHORD Pendulum through PCB M R R F Lifting Cum Lining M Cant Rail Datum Rail Machine Working Direction F

LEVEL CORRECTION: Concept of GENERAL LIFT • For carrying out attention to longitudinal profile, one rail is kept as Base or Datum Rail. • Datum Rail selection: • On curves- inner-rail. • On straight track -Less disturbed/higher Rail • Rail Selector Switch: • In tampers supplied by Plasser India, Selector Switch is provided to select cant rail, the other rail becomes the datum Rail (Base Rail). • In Russian Tamper, Selector Switch is provided for selecting datum Rail

LEVEL CORRECTION- Selection of General Lift • It is the amount of lift given to cover all undulations, for Datum Rail and is fed through front tower • It is decided on the basis of magnitude of the dips/peaks generally available in the track. • Dips and peaks are decided on preliminary survey of Datum rail in chord equal to machine chord length (15 m) approximately for eliminating short wave defects. • Normally General Lift is taken as the algebraic difference of higher and lower point of Base rail + 10 mm. • Why General Lift ? • It ensures packing at all locations. • Reduces the defect size. • It shifts the defect location.

RAMP-UP / RAMP-DOWN OF GENERAL LIFT • Ramping up & down - at the rate of 1 in 1000 • Starting of tamping by providing Ramping up from Zero lift to required General Lift and at the end of Closing block, lift is reduced to zero by ramping down • In next block beginning of ramp up should start at the same place from where ramp down of previous block was started Required Track Level Ramping UP Ramping Down Ramping UP Existing Track

GENERAL LIFT ON CURVE ? Assuming Datum Rail is in perfect level i. e no undulations in datum rail Designed SE = 30 Existing Maximum SE = 60 mm Existing Minimum SE = 20 mm Given General Lift = 20 mm 30 mm 20 mm Case - 1 At the location of Existing SE less than Designed SE say 20 mm Steps of correction by machine • Machine will Lift Datum Rail by 20 mm • Net SE left = 20 -20 = 00 mm • SE Fed = 30 mm (Designed SE) • Machine will lift outer Rail by 30 mm (with reference to datum rail)

GENERAL LIFT ON CURVE Case - 2 : At the location of Existing SE More than Designed SE say 60 mm Designed SE = 30 Given General Lift = 20 mm Existing Maximum SE = 60 mm Existing Minimum SE = 20 mm 30 mm 60 mm 40 mm 20 mm Steps of correction by machine • Machine will Lift Datum Rail by 20 mm • Net SE left = 60 -20 = 40 mm • SE Fed = 30 mm • But existing level difference is already 40 mm (> designed SE value) • At this location lowering of track by 10 mm is required to get designed SE i. e. 30 MM, but since machine cannot lower the track and hence after packing SE will be 40 mm and not 30 mm.

GENERAL LIFT ON CURVE Case - 3 : General Lift = Maximum Existing Cant – Designed Cant Designed SE = 30 Existing Maximum SE = 60 mm General Lift = 60 – 30 = 30 mm 60 mm 30 mm Steps of correction by machine • Machine will Lift Datum Rail by 30 mm • Net SE left = 60 -30 = 30 mm • SE Fed = 30 mm • But existing level difference is already 30 mm (= designed SE value) • Hence at this location no lifting will be done and only packing will be done by machine but designed SE will be achieved.

GENERAL LIFT Conclusion For straight track General Lift = Algebraic difference of higher and lower point of Base rail + 10 mm. For Curves, Case-1 : Existing max. Super-elevation (SE) < Designed SE General Lift = Algebraic difference of higher and lower point of Base rail (inner rail) + 10 mm. Case-2: Existing max. Super-elevation (SE) > Designed SE General Lift = Algebraic difference of higher and lower point of Base rail (inner rail) + max difference between existing and designed SE (i. e. Maximum Existing Cant – Designed Cant).

GENERAL LIFT FEEDING (At Front Tower)

GENERAL LIFT FEEDING (At Front Tower) Detail about Machine DUO 08 -32 C (RM=5300 mm. MF=9350 mm. RF=14650 mm) Length of ramp in and ramp out = 30 * 1000 = 30, 000 mm No. Of sleepers in which this ramp is achieved = 30, 000/600 = 50 No. Of sleepers in length RM(a) = 5. 3/0. 6 = 9 No. Of sleeper in length MF(b) = 9. 35/0. 6 = 16 Rate of lift per sleeper = 30/50 = 0. 6 mm So, feeding of lift value on 66 sleepers in ramp in will be 66 X 0. 6 = 39. 6 mm (40 mm) Lift at other locations can accordingly be calculated.

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DIP IN TRACK 37

FRONT TROLLEY ON DIP DEFECT DIP CREATED 38

LIMITATIONS OF SMOOTHENING MODE • The track may have defects of varying wave lengths • Machines have limited chord length, so the correction achieved by smoothening mode will certainly have residual defects on different wave lengths • Therefore, by tamping in smoothening mode, the amplitude of defect reduces and the peak location is also shifted towards opposite the direction of machine working because of transfer function.

LIFTING Vs SETTLEMENT • Track undergoes settlement after lifting. • Part of settlement takes place early say 2 -3 GMT. • This settlement takes place at relatively fast rate. Normally this part of settlement is achieved by DTS. • Still rate of settlement is high for first 3 months after tamping. So over-lifting may be designed to take care of settlement in first 3 months.

DESIGN OVERLIFT Maximum over lift of 30% can be provided by machine.

DESIGN LIFT • Long wave defects cannot be eliminated in smoothening mode • Concept of Design Lift and Over Lift

DESIGN LIFT Existing Track level Residual Error FR = Y * RM / RF Desired Track level R M Y F Residual Error = Y * RM / RF for CSM FR = Y * 3. 9 / 12. 80 = Y / 3. 282

REDUCTION RATIO Bogie Distance (m) 08 -275 UNIMAT 08 -275 -3 S 09 - 32 CSM UNIMAT Compact (MPT) T-Express (09 -3 X) 08 -32 C Duomatic RM(a) 3. 32 4. 85 3. 90 5. 10 4. 56 5. 3 MF(b) 8. 89 10. 73 8. 90 9. 05 10. 67 9. 35 RF(a+b) 12. 21 15. 58 12. 80 14. 15 15. 23 14. 65 Reduction Ratio (r) 3. 678 3. 212 3. 232 2. 775 3. 333 2. 764

METHOD FOR CALCULATING – Y (Lift) • Bench Marks fixing (Reference Points) • Decide datum rail • Recording of Actual Rail levels @10 m • Plotting of existing level on graph paper • Decide final track level and plot on same graph – considering high points, low points any other obligatory points • Formation Levels may also be plotted

METHOD FOR CALCULATING – Y (Lift) • Calculate lift at every station from graph • Alternatively- Calculate lift at every station by using software (TOP TRACK etc. ) • Interpolate lift amount on alternate/ 3 rd sleeper • Write down lift value on sleepers • Enter lift value into lift potentiometer (in front cabin)

FEEDING OF CANT (Super-elevation) • At Front Cabin i. e Front tower (F) location (Old machines). • At working Cabin i. e Measuring or Correcting (M) tower location (All new machines including CSM, TEXP and DUO etc. )

FEEDING OF CANT (From Working Cabin) TC T = 20 A = 20 T = 40 A = 40 CT C = 40 T = 20 A = 20 TS T=0 A=0 T – Theoretical designed value. A -- Actual value fed from working cabin. T=0 A=0

FEEDING OF CANT (From Front Cabin) DIRECTION OF WORK 3 5 4 2 1 TC 6 CT 1: n 7 ST R M TC F R R F M R 8 M R F M R M F R F M M F R- REAR REFERENCE POINT M- MEASURING POINT F- FRONT REFERENCE POINT R M R F M M F R F F M R M F

FEEDING OF CANT (From Front Cabin) R M b F a T – Theoretical designed value. A -- Actual value fed from front tower. T = 40 A = 52 (1 in 1000 and a is 12 m) TC CT T = 12 A=0 T = 28 A = 40 C = 40 ST T=0 A=0 a b T = 40 A = 40 T = 18 A = 18 T = 40 A = 40 a b T = 22 A = 22 T=0 A=0 T =0 A = -12 a b T=0 A=0

Level Adjustment (K - value) on Horizontal Curve K- adjustment on transition & circular curves Correction Values in Transition(? ) Circular Transition K K K= 50* SE / R

K- ADJUSTMENT ON TRANSITION & CIRCULAR CURVES K Correction to be deducted from general lift

K- ADJUSTMENT ON TRANSITION & CIRCULAR CURVES K- Correction to be deducted from general lift K-VALUE K K

K- ADJUSTMENT ON TRANSITION & CIRCULAR CURVES CT TC TS ST R=875 m SE=100 mm K=5. 714 mm 30 -5. 7=26. 3 mm 30 mm Reduced General Lift/lift

X- LEVEL ADJUSTMENT ON VERTICAL SUMMIT CURVES R M F General lift - Y Y Lifting will be done up to this level only R Correction = + X Adjustment / Correction X = Constant / R R = Radius of vertical curve Constant = Depends upon type of machine To be Added in General lift / Lift

X- LEVEL ADJUSTMENT ON VERTICAL SAG CURVES Adjustment / Correction X = Constant / R R = Radius of vertical curve Constant = Depends upon type of machine To be Subtracted from General lift / Lift R Lifting will be done up to this level even if zero lift is given R M F Correction = - X VERTICAL CURVE (SAG)

X- LEVEL ADJUSTMENT ON VERTICAL CURVES- WHY ? If X- Value is not fed Curve will flatten VERTICAL CURVE (SUMMIT) with each round of tamping WHERE ? M/s Plasser Machine : in of the machine Manual NT - CHAPTER VERTICAL CURVE (SAG)

LEVELLING MODES • Smoothening/Compensation mode • Feed General Lift • longitudinal levels of track are smoothened – short wave length defects within machine base removed but Long wave defect remains • Design mode • Feed Lift values (Target height) • Complete elimination of short/long wave length defects

ROLES OF SSE/ P. Way & Machine Operator Select proper datum rail General lift value in smoothening mode of working to be given to operator. Calculate and write Y/FD value over sleeper in design mode working. SE of curve as to be fed in machine (at F) at different locations to be written over sleepers. To be calculated in consultation with operator of different machines. K and X correction will be calculated and fed by operator on the basis of R and SE supplied by SSE/P. way.

Summery of feeds/Corrections applied in Lining and Levelling - Recap Smoothening mode working • General lift calculated and fed. • SE at different locations are calculated and written on sleepers. • K and X value calculated and fed by operator 3 -Point lining: Versines H, Ha, Hb, Hc and Hd calculated and written on sleepers 4 -Point lining: Versine correction Vm and V values calculated and written on sleepers

Summery of feeds/Corrections applied in Lining and Levelling - Recap Design mode working • Field survey for FD and Y value to be done and written on sleepers. • SE at different locations are calculated and written on sleepers. • Level correction values K and X calculated and fed by operator 3 -Point lining: Versines H, Ha, Hb, Hc and Hd calculated and written on sleepers

THANKS ALC SYSTEM IN MACHINE Versines H, Ha, Hb, Hc and Hd and Level adjustment correction K & X is calculated by machine itself.