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Railway noise Gijsjan van Blokland M+P Ard Kuijpers M+P sources:

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Presentation on theme: "Railway noise Gijsjan van Blokland M+P Ard Kuijpers M+P sources:"— Presentation transcript:

1 Railway noise Gijsjan van Blokland M+P Ard Kuijpers M+P sources:
Müller-BBM (D), D. Thompson (GB), M.Dittrich (TNO)

2 topics Relevance Sources Model of generation process of rolling noise
Propulsion noise Aero dynamic noise Model of generation process of rolling noise Force generation in wheel/rail contact Vibrational response of wheel and of rail Effect of parameter changes in wheel system and rail system Mitigation measures Special constructions Curve squeal Generation process

3 Dose-effect relation for three transport noise sources

4 Sources of railway noise (I)
Areo-dynamic Propulsion system Rolling wheel/rail system

5 Speed relation for the three noise sources

6 Sources of noise at high speed (>300 km/h)

7 Sound emission of train types

8 Bronnen en snelheid (II)
aerodynamisch rolgeluid geluidniveau rolgeluid bij afscherming >350 km/h snelheid

9 Rolling noise

10 Effect of braking system on wheel roughness and sound production
Wavelength translated to frequency: f=v/λ Cast iron blocks lead to significant roughness of the wheel rolling surface due to local high temperatures during braking Disc brakes causes no roughness build-up Disc + blocks is the worst combination Replacing cast iron blocks with composite blocks improves noise characteristics

11 level of rail roughness
Rail surface is not completely flat, rail roughness increases by use Cause not fully understood Worst situation is periodic irregularity with a 4 cm wavelength f=v/λ: 4 cm at 40 m/s equals 1 kHz

12 Rail corrugation, wavelength of 4 cm clearly visible

13 Combined wheel/rail roughness (dB re 1 m)

14 Modeling rolling noise (1): force generation

15 Modeling rolling noise (2): force  sound radiation

16 Contribution to rolling noise

17 Wheel/rail force reception: mobility (velocity/force) wheel: modal system rail: no boundery, regular support by sleepers

18 Wheel: modes of vibration
Calculated using FEM Showing exaggerated cross-section deformation of each mode

19 Radiation efficiency σ: log of ratio of sound/vibration

20 Vibration of track system

21 Rail pad defines coupling between rail and sleeper
high stiffness pad  strong coupling  good energy transfer from (low damped) rail to (high damped) sleepers

22 Track vibration: effect of pad stiffnes

23 Effect of pad stiffnes on vibration and noise level
Increased stiffnes baseplate pad Rail noise level difference (dB)

24 Dependence of rolling noise on pad stiffness

25 Radiation efficiency of rail

26 Rail cross-section deformations - only relevant at higher frequencies - not relevant for total dB(A) level

27 Contribution to rolling noise (again)

28 Speed related wheel and rail contribution
total rail Noise level wheel speed

29 Model of rolling noise (Twins)

30 Reducing rolling noise

31 Effect of braking system on roughness and noise

32 Rail grinding Reduces rail rougnes
Regular grinding: longer wavelengths Acoustic grinding: 1mm – 63cm Acoustic effect: 2-4 dB(A) Effect depending on wheel rougness

33 Effect of rail grinding after some years

34 Effect of wheel shape

35 Effect of types of wheel damping

36 Effect of wheel geometry

37 Effect of pad stiffness

38 types of rail dampers

39 ISVR/CORUS damper

40 Effect of damper

41 Skirts (vehicle mounted barriers)
Only effective in combination with track mounted barriers

42 Mini barriers mecahnism: effect: 5 dB(A) for rail contribution
Mainly sheilding of rail radiation Added absorption is essential (to prevent multiple reflections) effect: 5 dB(A) for rail contribution

43 Results Metarail Project
Influence on Noise

44 Cost-benefit study of mitigation measures
Calculate costs & benefits for different noise control strategies. Strategies consist of combinations of noise control measures. Two major freight freeways chosen for study. Rotterdam Köln Basel Milano Bettembourg Lyon 1177 km 490 km Total line length: 1667 km

45 Instruments for strategic noise abatement Cost-Benefit Analysis
max. 4 m barriers track system improvement max. 2 m barriers Scenarios of Noise reduction due to rolling stock improvement - 10 dB - 5 dB none rolling stock improvement only

46 Non-standard rail construction (slab track)
Preferred construction for high speed lines in Germany and Netherlands Stable system , even at soft soil Low maintenance High initial costs

47 Types of track construction
Elasticity in track system is essential to prevent cracks in rail Conventional ballast track Flexible mounted sleepers in concrete slab Rigid mounted sleeper in concrete slab Rail directly mounted in slab

48 Case: HSL-Zuid

49 Slab tracks are more noisy then conventional ballast tracks. Why?
Less tight rail to sleeper connection  less damping No acoustic absorption from ballast Total effect +2 tot +5 dB(A

50 Effects of slab track

51 Noise increase due to higher rail contribution
TWINS: verschil ballast – 240 km/h: Hz ballast track Slab track (Rheda) total wheel rail/ baseplate Sleeper/ slab

52 Noise difference ballast – slab track as a function of frequency
125 250 500 1000 2000 4000 8000 -10 -5 5 10 15 20 frequentie [Hz] L p,UIC 54 beton kaal - L p,UIC 54 ballast [dB(A)] Goederen (Best) ICR (Best) Goederen (Deurne) ICR (Deurne) Effect centered around 800 Hz, rail contribution

53 optimal dynamic properties
Noise improved design Higher rail damping Tighter connection with sleeper Damped fixation of sleeper in slab Cork-rubber with optimal dynamic properties

54 Noise improved design, adding of absorption
German slab track construction

55 Curve squeal

56 Curving behavior


58 Creep force

59 Reducing squeal noise

60 Some general points

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