Experimental study of elevated MRT rail noise study of elevated...Lunar New Year Eve Mid-Fall Festival 2004/5/28 Shing Chen: Experimental study of elevated MRT rail noise 11 Train

2004/5/28 Shing Chen: Experimental study of elevated MRT rail noise 1

Experimental study of elevated MRT railnoise

Shing ChenIndustrial Technology Research Institute

[email protected]


Objectives

•Find a suitable way to evaluate the insertionloss of noise barriers for elevated MRTtrains when a reference microphone positionis not available according to ISO 10847 orANSI S12.8.–train noise characteristics


Insertion loss (IL) of noise barriers

•In-situ determination–ISO 10847, ANSI S12.8–Need a “reference microphone position”

•IL= (Lp –Lref)before –(Lp –Lref)after–(Lp –Lref)before : SPL before noise barriers is installed–(Lp –Lref)after : SPL after noise barriers is installed–Lp: SPL at receiver position–Lref: SPL at reference position


Reference microphone position

•avoiding near field, reflection, diffractioneffects

•ISO 10847 & ANSI S12.8–at least 1.5 m above the barrier top–10° greater than to the top of the barrier

•distance from source to barrier is less than 15m


ANSI S12.8& ISO 10847


Noise barriers in an elevated MRT viaduct•Reference microphone position is not available

–distance is less than 10 cm or 15 cm from noise barrierto vehicle clearance envelope

–vehicle safety

proposedbarrier

vehicle clearanceenvelope


Insertion loss (IL) of noise barrierswithout a reference microphone in an

elevated MRT viaduct

•IL= (Lp)before –(Lp)after–(Lp)before : SPL at receiver position before noise barriers

is installed–(Lp)after : SPL at receiver position after noise barriers is

installed•Train noise characteristics:

–passenger loading is periodical with time in a widesense

–non-steady–intermittent


Number of passengers/day, year 20042004

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

四日三六三六一四日三week day

num

bero

fpas

seng

ers/

day

Lunar New Year Eve



100,000

300,000

500,000

700,000

900,000

1,100,000

1,300,000

1,500,000

三六二五一四日三六二五一四日三六二五一四日三六二五一四日三六二五一四日三六

week day

num

bero

fpas

seng

ers/

day

SARSLunar New Year Eve

Mid-Fall Festival



100,000

300,000

500,000

700,000

900,000

1,100,000

1,300,000

1,500,000

二五一四日三六二五一四日三六二五一四日三六二五一四日三六二五一四日三六二五

week day

num

bero

fpas

seng

ers/

day

Lunar New Year Eve Mid-Fall Festival


Train noise at controlledrunning conditions

0.5m

F8

F2

F3

F4

F5

F6

F7

4m


Controlled conditions: Repeated Trainnoise levels

SPL max difference: 1.7 dB(A)SPL difference average: 0.6 dB(A)

train speed at 80 km/hrwithout passengers(test date: 2002/09/14)

microphone numberF2 F3 F4 F5 F6 F7 F8

trainset

SEL Lmax SEL Lmax SEL Lmax SEL Lmax SEL Lmax SEL Lmax SEL Lmax

1st east bound 97.9 91.8 97.4 90.8 97.2 90.5 96.8 90.2 96.4 89.9 95.8 89.1 94 87.32nd east bound 97.8 90.9 97.3 90.2 97 90.1 96.7 89.2 96.3 88.7 95.6 88.2 93.7 86.11st west bound 100 93.8 99 92.6 98.8 92.3 98.7 91.6 98 91.1 97.5 90.4 95.7 88.6

01/02

2nd west bound 98.5 92.7 97.8 91.9 97.6 91.5 97.3 91 96.8 90.2 96.2 89.9 94.5 88.11st east bound 99 92.2 98.9 92.1 99.1 92.4 98.6 92 97.8 91.1 97.3 90.5 95.6 88.72nd east bound 99 92 98.8 91.7 99 92.1 98.5 91.9 97.7 91.0 97.2 90.5 95.5 88.71st west bound 98.6 91.5 98.7 92.1 98.5 91.6 98.4 92 97.9 91.5 97.3 90.9 95.5 89.1

107/108

2nd west bound 98.3 92.4 99.3 93.1 99 93.3 98.7 92.4 98.4 92.2 97.6 91.2 95.8 89.4


Receiver’s positions

down track︰P1,P2,P3,P4,P5up track︰P6,P7,P8,P9,PR

unit: m

Proposedbarrier


Uncontrolledconditions:

Repeated noiselevels of sametrain set in one

service day

• test site: R20R21P1• test date: 2002/09/04

85

90

95

100

105

110

00:32

:44

06:11

:50

08:11

:56

10:14

:38

12:15

:11

14:14

:12

16:15

:10

18:14

:43

20:08

:31

time

SEL

,dB

(A)

up track,107&108

2

23

1

31

1

1

1

85

90

95

100

105

110

06:27:1

2

09:07:4

1

10:27:2

4

11:51:4

9

14:27:3

4

15:49:1

9

17:11:2

2

18:24:4

9

20:02:4

9

21:23:5

2

22:42:3

8

time

SEL

,dB

(A)

up track ,01&02

2

1

1

2

3

13

21

2

1

SPL max difference: 12 dB(A)


75.0

80.0

85.0

90.0

95.0

100.0

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

)SELLmax

R20R21P1, up track70.0

75.0

80.0

85.0

90.0

95.0

04:33:36 06:57:36 09:21:36 11:45:36 14:09:36 16:33:36 18:57:36 21:21:36 23:45:36

time

dB(A

)

SELLmax

R20R21P1,down track

individual train noise level in one service day

70.0

75.0

80.0

85.0

90.0

95.0

04:48:00 07:12:00 09:36:00 12:00:00 14:24:00 16:48:00 19:12:00 21:36:00 00:00:00

time

dB(A

)

SELLmax


75.0

80.0

85.0

90.0

95.0

04:48:00 07:12:00 09:36:00 12:00:00 14:24:00 16:48:00 19:12:00 21:36:00 00:00:00

time

dB(A

)

SELLmax

R20R21P5, down track

70.0

75.0

80.0

85.0

90.0

95.0

04:48:00 07:12:00 09:36:00 12:00:00 14:24:00 16:48:00 19:12:00 21:36:00 00:00:00

time

dB(A

)

SELLmax


75.0

80.0

85.0

90.0

95.0

04:48:00 07:12:00 09:36:00 12:00:00 14:24:00 16:48:00 19:12:00 21:36:00 00:00:00

time

dB(A

)

SELLmax


•test date: 2003/08/29


Statistics of train noise levelsin one service day

•railhead grinding: May 2003.

up track down track2002/09/04 2003/08/29 2002/09/04 2003/08/29site noise

level averagevalue

standarddeviation

averagevalue

standarddeviation

averagevalue

standarddeviation

averagevalue

standarddeviation

SEL 101.3 3.7 93.5 2.1 95.9 3.8 90.4 1.1R20R21P1Lmax 93.6 3.9 85.2 2.5 88.1 4.2 82.5 1.3SEL 93.0 2.1 87.2 1.7 92.9 1.7 90.8 0.9R20R21P5Lmax 84.4 2.3 78.9 2.2 84.8 1.8 83.3 1.2SEL 97.2 3.0 89.4 1.7 94.5 3.5 88.8 1.1R20R21P9Lmax 88.8 3.4 81.3 2.0 86.6 3.7 81.0 1.4


Averagenoise levelsof 20 trains

in oneservice day( test date:

2003/08/29)

82

84

86

88

90

92

94

96

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

timedB

(A) SEL

Lmax

R20R21P1, up track80

82

84

86

88

90

92

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

) SELLmax

R20R21P1,down track

76

78

80

82

84

86

88

90

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

) SELLmax


82

84

86

88

90

92

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

) SELLmax


78

80

82

84

86

88

90

92

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

) SELLmax


80

82

84

86

88

90

04:48:00 08:24:00 12:00:00 15:36:00 19:12:00 22:48:00

time

dB(A

) SELLmax



Statistics of average noise levels of 10trains and 20 trains in one service day

• railhead grinding: May 2003.

up track down track2002/09/04 2003/08/29 2002/09/04 2003/08/29site no. of

trainsnoiselevel average

valuestandarddeviation

averagevalue

standarddeviation

averagevalue

standarddeviation

averagevalue

standarddeviation

SEL 102.3 2.0 93.4 1.0 97.6 2.4 90.3 0.410Lmax 94.7 2.1 85.2 1.1 90.0 2.5 82.5 0.4SEL 102.4 1.6 93.4 0.8 97.9 1.8 90.3 0.4

R20R21P120

Lmax 94.8 1.8 85.2 0.9 90.3 1.9 82.5 0.3SEL 93.4 0.8 87.2 0.8 93.2 0.6 90.8 0.410Lmax 84.8 0.8 78.9 1.0 85.1 0.7 83.2 0.4SEL 93.4 0.5 87.2 0.6 93.2 0.4 90.8 0.3

R20R21P520

Lmax 84.8 0.5 78.9 0.7 85.1 0.5 83.2 0.3SEL 98.1 0.9 89.4 0.7 95.8 1.2 88.8 0.310 Lmax 90.0 1.1 81.3 0.9 87.9 1.5 81.0 0.3SEL 98.2 0.6 89.4 0.5 95.8 0.9 88.8 0.2

R20R21P920 Lmax 90.0 0.7 81.3 0.6 87.9 1.0 81.0 0.2


Conclusions

• Insertion loss of noise barrier for an elevated MRT viaduct(Lp)before –(Lp)after,–may be conservative since the noise level from trains may be

increased due to the degradation of wheel/rail interaction•Sample sizes: 20 trains•Noise measurement time for (Lp)before and (Lp)after,

– same week day– same train schedule– time period between (Lp)before and (Lp)after : as short as possible

•No any railroad work or wheel grinding during the timeperiod between (Lp)before and (Lp)after


Documents

Experimental study of elevated MRT rail noise study of elevated...Lunar New Year Eve Mid-Fall Festival 2004/5/28 Shing Chen: Experimental study of elevated MRT rail noise 11 Train