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

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Presentation on theme: "Railway noise Gijsjan van Blokland M+P Ard Kuijpers M+P sources: Müller-BBM (D), D. Thompson (GB), M.Dittrich (TNO)"— 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 railway noise 2 topics  Relevance  Sources  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  Mitigation measures

3 railway noise 3 Dose-effect relation for three transport noise sources

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

5 railway noise 5 Speed relation for the three noise sources

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

7 railway noise 7 Sound emission of train types

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

9 railway noise 9 Rolling noise

10 railway noise 10 Effect of braking system on wheel roughness and sound production  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 Wavelength translated to frequency: f=v/λ

11 railway noise 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 railway noise 12 Rail corrugation, wavelength of 4 cm clearly visible

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

14 railway noise 14 Modeling rolling noise (1): force generation

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

16 railway noise 16 Contribution to rolling noise

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

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

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

20 railway noise 20 Vibration of track system

21 railway noise 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 railway noise 22 Track vibration: effect of pad stiffnes

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

24 railway noise 24 Dependence of rolling noise on pad stiffness

25 railway noise 25 Radiation efficiency of rail

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

27 railway noise 27 Contribution to rolling noise (again)

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

29 railway noise 29 Model of rolling noise (Twins)

30 railway noise 30 Reducing rolling noise

31 railway noise 31 Effect of braking system on roughness and noise

32 railway 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 railway noise 33 Effect of rail grinding after some years

34 railway noise 34 Effect of wheel shape

35 railway noise 35 Effect of types of wheel damping

36 railway noise 36 Effect of wheel geometry

37 railway noise 37 Effect of pad stiffness

38 railway noise 38 types of rail dampers

39 railway noise 39 ISVR/CORUS damper

40 railway noise 40 Effect of damper

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

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

43 railway noise 43 Results Metarail Project Influence on Noise

44 railway noise 44 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 Bettembour g Lyon 1177 km 490 km Total line length: 1667 km Cost-benefit study of mitigation measures

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

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

48 railway noise 48 Case: HSL-Zuid

49 railway noise 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 railway noise 50 Effects of slab track

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

52 railway noise 52 Noise difference ballast – slab track as a function of frequency 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 railway noise 53 Noise improved design  Higher rail damping  Tighter connection with sleeper  Damped fixation of sleeper in slab Cork-rubber with optimal dynamic properties

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

55 Curve squeal

56 railway noise 56 Curving behavior

57 railway noise 57

58 railway noise 58 Creep force

59 railway noise 59 Reducing squeal noise

60 railway noise 60 Some general points

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