Railway noise
Gijsjan van Blokland M+P
Ard Kuijpers M+P
sources:
Müller-BBM (D),
D. Thompson (GB),
M.Dittrich (TNO)
topics
 Relevance
 Sources
 Rolling noise
 Propulsion noise
 Aero dynamic noise
 Model of generation process of rolling noise
railway noise
 Force generation in wheel/rail contact
 Vibrational response of wheel and of rail
 Effect of parameter changes in wheel system and rail system
2
 Mitigation measures
 Special constructions
 Curve squeal
 Generation process
 Mitigation measures
railway noise
Dose-effect relation for three transport noise
sources
3
Sources of railway noise (I)
railway noise
Areo-dynamic
4
Propulsion
system
Rolling wheel/rail system
railway noise
Speed relation for the three noise sources
5
railway noise
Sources of noise at high speed (>300 km/h)
6
Sound emission of train types
emissiegetal [dB(A)]
70
5
1
65
4
9
3
7
6
8
railway noise
60
7
2
55
50
40
60
80
100
140
160
snelheid [km/h]
200
Bronnen en snelheid (II)
8
geluidniveau
railway noise
aerodynamisch
rolgeluid
rolgeluid bij
afscherming
>350 km/h
snelheid
railway noise
Rolling noise
9
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
railway noise
 Disc brakes causes no
roughness build-up
10
 Disc + blocks is the
worst combination
 Replacing cast iron
blocks with composite
blocks improves noise
characteristics
Wavelength translated to
frequency: f=v/λ
level of rail roughness
 Rail surface is not
completely flat, rail
roughness increases
by use
railway noise
 Cause not fully
understood
11
 Worst situation is
periodic irregularity
with a 4 cm
wavelength
 f=v/λ: 4 cm at 40 m/s
equals 1 kHz
railway noise
Rail corrugation, wavelength of 4 cm clearly visible
12
railway noise
Combined wheel/rail roughness (dB re 1 m)
13
railway noise
Modeling rolling noise (1): force generation
14
railway noise
Modeling rolling noise (2): force  sound radiation
15
railway noise
Contribution to rolling noise
16
Wheel/rail force reception: mobility (velocity/force)
railway noise
wheel: modal system
rail: no boundery, regular support by sleepers
17
Wheel: modes of vibration
railway noise
 Calculated using FEM
18
 Showing exaggerated
cross-section
deformation of each
mode
railway noise
Radiation efficiency σ: log of ratio of sound/vibration
19
railway noise
Vibration of track system
20
Rail pad defines coupling between rail and sleeper
 high stiffness pad  strong coupling  good energy transfer from
railway noise
(low damped) rail to (high damped) sleepers
21
railway noise
Track vibration: effect of pad stiffnes
22
Effect of pad stiffnes on vibration and noise level
Aeq
difference (dB)
Rail noise level
L
[dB]
railway noise
12
25 MN
10
30 MN
8
40 MN
70 MN
6
4
2
Increased stiffnes
baseplate pad
0
-2
-4
-6
-8
63
125
250
500
1000
octave band frequency [Hz]
23
2000
4000
8000
railway noise
Dependence of rolling noise on pad stiffness
24
railway noise
Radiation efficiency of rail
25
Rail cross-section deformations
- only relevant at higher frequencies
railway noise
- not relevant for total dB(A) level
26
railway noise
Contribution to rolling noise (again)
27
Speed related wheel and rail contribution
total
28
Noise level
railway noise
rail
wheel
speed
railway noise
Model of rolling noise (Twins)
29
railway noise
Reducing rolling noise
30
railway noise
Effect of braking system on roughness and noise
31
Rail grinding
 Reduces rail
rougnes
 Regular grinding:
longer wavelengths
 Acoustic grinding:
1mm – 63cm
railway noise
 Acoustic effect: 2-4
dB(A)
32
 Effect depending on
wheel rougness
railway noise
Effect of rail grinding after some years
33
railway noise
Effect of wheel shape
34
railway noise
Effect of types of wheel damping
35
railway noise
Effect of wheel geometry
36
railway noise
Effect of pad stiffness
37
railway noise
types of rail dampers
38
railway noise
ISVR/CORUS damper
39
railway noise
Effect of damper
40
Skirts (vehicle mounted barriers)
railway noise
 Only effective in combination with track mounted barriers
41
Mini barriers
 mecahnism:
 Mainly sheilding of rail radiation
 Added absorption is essential (to prevent multiple reflections)
railway noise
 effect: 5 dB(A) for rail contribution
42
Results Metarail Project
Influence on Noise
Stiffness of ballast
Distance of sleepers
railway noise
Track width
43
Corrugation of rail
Pad stiffness
Corrugation of wheel
Diff. Noise dB(A)
Type of rail
9
8
7
6
5
4
3
2
1
0
Type of Influence
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.
Ham b u rg
railway noise
Lo n d o n
A n t w erp en
490 km
Köln
Bettembour
g
Basel
Lyon
Milano
M ain z
Paris
Rotterdam
1177 km
Basel
Ly o n
Bo rd eau x
M arseille
Total line length: 1667 km
44
Ro t t erd am
M ilan o
Instruments for strategic noise abatement
Cost-Benefit Analysis
Costs and benefits
not including costs for insulated windows max. 4 m barriers
45
Benefits (reduction
persons > 60 dB/km)
railway noise
track system improvement
max. 2 m barriers
300
Scenarios of
Noise reduction
due to rolling stock
improvement
250
200
10
dB
150
-
- 5 dB none
100
50
0
0
20000 40000 60000 80000 100000 120000
Costs (EURO/km/year)
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
Types of track construction
 Elasticity in track system is essential to prevent cracks in rail
Conventional ballast track
railway noise
Flexible mounted sleepers in
concrete slab
47
Rigid mounted sleeper in
concrete slab
Rail directly mounted in slab
railway noise
Case: HSL-Zuid
48
Slab tracks are more noisy then conventional
ballast tracks. Why?
 Less tight rail to sleeper connection  less damping
 No acoustic absorption from ballast
railway noise
 Total effect +2 tot +5 dB(A
49
railway noise
Effects of slab track
50
Noise increase due to higher rail contribution
TWINS: verschil ballast – Rheda @ 240 km/h: 250 -1000 Hz
ballast track
Slab track (Rheda)
total
railway noise
wheel
51
rail/
baseplate
Sleeper/
slab
Noise difference ballast – slab track
as a function of frequency
20
Goederen
(Best)
Goederen
(Best)
ICR (Best)
ICR (Best)
Goederen (Deurne)
15
52
Effect centered around
800 Hz, rail contribution
Lp,UIC 54 beton kaal - Lp,UIC 54 ballast [dB(A)]
railway noise
Goederen
(Deurne)
ICR (Deurne)
ICR (Deurne)
10
5
0
-5
-10
125
250
500
1000
frequentie [Hz]
2000
4000
8000
Noise improved design
 Higher rail damping
 Tighter connection with sleeper
 Damped fixation of sleeper in slab
railway noise
Cork-rubber with
optimal dynamic properties
53
Noise improved design, adding of absorption
railway noise
German slab track construction
54
Curve squeal
railway noise
Curving behavior
56
57
railway noise
railway noise
Creep force
58
railway noise
Reducing squeal noise
59
railway noise
Some general points
60