UIC 518

Scope Rules for conducting dynamic behaviour tests for Safety Track fatigue Ride quality Test on tracks matching actual service conditions If actual conditions are better, use enhanced operating condition and vice versa

Field of Application Tests to be carried out when New vehicle /suspension Redesigned suspension Revised operating conditions Additional requirements on specific cases like tilting (cant deficiency compensation) device on suspensions

Parameters Recorded Wheel -rail level Lateral force at Axle box level Vertical Force Lateral acceleration Lateral force at Axle box level Bogie level lateral & vertical acceleration Body level lateral & vertical acceleration Equivalent conicity of wheel set

General Principles of Testing Acceptance based on dynamic behaviour of line-test On well-defined parameters related to Track quality Vehicle characteristics, incl max operating speed Track Test zones Tangent (straight) Large-radius curve Small curve

General Principles of Testing (contd.) Measuring method Normal-> rail-wheel interaction forces are recorded Simplified-> rail-wheel forces and some other parameters are not recorded Normal method for new vehicle Detailed procedure for selection of parameters for simplified method depending on Type of design/operational change Type of vehicle

General Principles of Testing (contd) Location/type of measurement on body and bogie depends on For locomotive-> no of axles per bogie, type of service and speed For coaches-> speed and bogie/non-bogie For wagons-> no of axles per bogie For dept vehicles-> special features

Running Test Conditions All combinations of Speed Cant deficiency Curve radius Test zone Number of sections No overlap between sections May or may not be juxtaposed sections

Test Zones Min 25 sections of straight total length > 10 kms Each section of 250m (±10%) for speed < 220 km/h Large radius curve Min 25 sections with cant <= 1.1* (max permissible cant) Include min 10 sections of cant =1.1* (max permissible) Total length >10kms Each section of 100-500m depending on max speed 10% higher than planned service speed

Test Zones (contd) Small radius curve of radius between 400- 600m, mean 500±50m, speed of 120- 80km/h Min 50 sections of cant <= 1.1*(max permissible cant) Include min 10 sections of cant = 1.1*(max permissible) Each section of 100 m ±10% Small radius curve of radius between 250- 400m, mean 300m, speed of 120- 80km/h Min 25 sections of cant <= 1.1*(max permissible) Include min 5 sections of cant = 1.1*(max permissible) Each section of 70 m ±10%

Test Zones (contd) Transitions for all types of curves to be treated as separate section Only one section per transition Include all transitions of selected curves Minimum total test zone length about 27 kms Straight +large curve =10+10 = 20kms Curve of 400-600 m radius =50*.9*100m = 4.5km Curve of 250-400 m radius =25 *.9*70m = 1.575km 4 transitions = 4*200m =.8 kms

Track Geometric Quality Track geometry parameters Unevenness Alignment Twist Gauge Track maintenance criteria limit for each of above QN1, if exceeded-> monitoring/ regular maintenance QN2, if exceeded-> short term maintenance QN3, if exceeded-> undesirable/ unsafe

Track Geometric Quality (contd) For track measuring (recording) cars Speeds of 200km/h Min wavelength 3m Max wavelength 25 m Track Quality based on Standard deviation of both unevenness & alignment Peak values for maintenance guidance and exclusion when QN3 limits are exceeded

Track Quality for Test Zone Based on standard deviations of alignment and unevenness calculated for either Entire length of each section 10 m sliding interval Test zones should be 50% better than QN1,40% between QN1 and QN2, 10% between QN2 and QN3 QN1, QN2, QN3 limits vary with test speed Exclude section where isolated peaks cross QN3 Twist & gauge should match railway's limits

Geometry of Rail-wheel contact If unstable dynamic behaviour of test vehicle on straight/large radius curve Calculate effective conicity based on Actual rail profile Actual wheel profile Amplitude of lateral wheel movement =3mm Compare with maximum permitted value, which is inversely related to speed

Test Vehicle Condition For air suspension, also test on deflated condition Test under unloaded and normal service load Extraordinary loading also for sub-urban stock Naturally worn wheel profile New wheel profile if effective conicity change in service less than 50% or .05 Effective conicity based on 1435 mm track gauge, 3mm amplitude of lateral wheel movement

Test Vehicle Condition (contd.) For hauled test vehicle, it should be rearmost with loose coupling For loco, test under hauling condition Test in both directions Or instrument the bogie which is in unfavorable position Dry rail condition Record atmospheric condition and time

Data Analysis For each section, calculate following parameters, abs(0.15th ) & 99.85th percentile of all dynamic parameters. Both values to be treated as readings of same parameter Median for quasi-static parameters on curves Weighted rms of vehicle accelerations for ride quality assessment Moving rms value over 100m after every 10m

Data Analysis (contd.) Sampling frequency >=200 Hz For each parameter, group values of all sections to calculate Mean, Xmean Standard deviation, sd Estimate maximum value, Xmax of each parameter

Data Analysis (contd.) Xmax= Xmean+k*sd , k varies from 0 to 3 depending on confidence level and parameter type Use two dimensional regression to estimate effect of speed/cant for quasi-static parameters Modify estimation process for any parameter which is known to have other than normal distribution

Efficient Estimate? Number of sections, N = 30, No of data samples/section, B= 1286 At 140 km/h, DAQ sampling rate 200 samples/sec u is sample mean, s = sample standard deviation Under UIC system, if no of data points n = 30 Estimate of Xmean= u ±2.04 sdest/√n (student's t- distribution) Estimate of sd, sdest = s – s*√(n-1)/Chi0.975 (= 0.8822*s) = s + s*√(n- 1)/Chi0.025 ( = 1.3366*s) Estimated Error in Xmax = 3*2.04*.3366*sd/√30 = 0.3761*s

Efficient Estimate? (contd) If all data points are considered, Taken either as single/multiple samples Since N*B = 38580 >>100, Estimate of Xmean= u ±1.96 sdest/√(N*B) = u ±.01*sdest (student's t-distribution same as normal distribution for large sample size ) Estimate of sd, sdest = s ±s/√(2N*B) = s ±.0036s Estimated Error in Xmax = 3*.01*.0036*s = 0.00011*s If sd = .15g, UIC has .056g error margin against 0.00002g of above method

Acceptance limits Lateral force2m = A*(10+axle load/3), A depends on vehicle and track structure Hy/Q =0.8 for radius of curve ≥ 250m Vertical and lateral body accelerations Peaks 2.5 to 5 m/s2 , depending on vehicle type 0.5 to 2m/s2 rms values, depending on vehicle type 1.3 to 1.5 m/s2 quasi-static lateral acceleration

Acceptance limits (contd.) Track fatigue limit (in kN) Vertical force, minimum of 90 +static axle load , for axle load up to 225 kN 160 to 200 kN, depending on limiting speed 145 kN for quasi-static force Quasi static lateral force 145 kN on curves 20Hz cut off frequency of filter

Desired Statistical Testing Get % of track in QN1,QN2,QN3 of Indian Railways Get dominant wave-length for each type of track Get corresponding resonance speeds for the bogie under consideration Check vehicle behaviour on resonant inputs in VCF lab Check if recorded values are within limits

Desired Statistical Testing (contd) Conduct oscillation trials on service track Ensure proportion of QN1,QN2,QN3 is same as Indian Railway track Cover 30*10(max. Wavelength) Resonant speeds of all dominant wavelengths Max speed Run at max speed on track having at-least 10 peaks in D category

Thank You!!!