3. NOISE IMPACT ASSESSMENT
3.1 Introduction
3.1.1 This chapter presents the potential noise impacts associated with the construction and operation of Spur Line. Cumulative impacts with other concurrent projects are also addressed. Mitigation monitoring and audit requirements are described.
3.1.2 The railway operation noise assessment is based on train speed profile and alignment information supplied by KCRC up to 10 November 1999.
3.2
Noise Assessment Criteria
Construction
Phase
3.2.1 Under Technical Memorandum (TM) on Environmental Impact Assessment Process, the day-time noise criterion is 75 dB(A). The criterion for educational establishment is 70 dB(A) on normal days and 65 dB(A) during examination periods.
3.2.2 Should works be required during restricted hours, i.e. 1900 to 0700 hours or at any time on a general holiday, a Construction Noise Permit (CNP) must be obtained before works are allowed to take place. Percussive piling works are also subjected to licensing under the Noise Control Ordinance (NCO).
Operational
Phase
3.2.3 Railway operation noise must comply with the standards specified[1]. These include:
• maximum A-weighted sound pressure level, Lmax
at 85 dB (2300 – 0700 hours); and
• the Acceptable Noise Levels (ANL) for the
appropriate Area Sensitivity Rating (ASR)[2].
The ANLs for 07:00 to 23:00 hours and 23:00 to 07:00 hours daily are 60/65/70
and 50/55/60 dB(A) for ASRs A/B/C respectively.
3.2.4 Noise from fixed plant must be limited to:
• 5 dB(A) below the ANL for the appropriate
ASR[3],
or
• not more
than the prevailing background noise levels.
3.2.5
In any event, the ASR assumed in this EIA report is
for indicative assessment only given that details of the plant layout are not
yet available. It should be noted that fixed noise sources are controlled under
Section 13 of the NCO. At the time of investigation, the Noise Control
Authority shall determine noise impact from concerned fixed noise sources on
the basis of prevailing legislation and practices being in force, and taking
account of contemporary conditions / situations of adjoining land uses. Nothing
in this EIA report shall bind the Noise Control Authority in the context of law
enforcement against any fixed or construction noise sources being assessed.
3.2.6 A complete set of environmental legislation and standards related to construction noise is given in Appendix A.
3.3 Representative Noise Sensitive Receivers
3.3.1 A site survey and desk study of government survey maps and Outline Zoning Plans were conducted to check the existing and planned land uses of all the noise sensitive receivers within 300 m of either side of the railway alignment. Representative Noise Sensitive Receivers (RNSRs) were selected from these noise sensitive receivers to represent both existing and future land uses worst affected by the proposed railway development. Where NSRs are represented by high rise buildings, the floor having direct line of sight, and having the shortest distance to the noise source, was selected for noise level calculations.
3.3.2 Figure 3.1 presents the locations of these RNSRs and the proposed land use of the area based on the information of the latest Outline Zoning Plans (OZPs) published for these areas. The OZPs referenced include S/FSS/8, S/NE-KTN/3, and S/YL-ST/1. Table 3.1 gives the details of each of these RNSRs and the type of noise sensitive land use they represent.
3.3.3
The future developments proposed under
the North East New Territories (NENT) Planning and Development Study is likely
to introduce new noise sensitive receivers to the Kwu Tung area. At present no details of specific
receivers are available and this noise assessment will therefore consider
representative NSRs
from information provided by the Project Proponent of the NENT Study.Any future
developments must take into account the presence of the Spur Line and the
findings of this assessment when considering their own environmental
requirements.
Table 3.1
Details of Representative Noise Sensitive Receivers
RNSR |
MPD at Ground Level |
Description of Existing Use |
No. of Storeys of Existing Use |
Description of Future Use Based on Outline Zoning
Plans and Approved Planning Applications |
Estimated No. of Storeys of Future Use |
Area Sensitivity Ratings * |
1 |
+9.7 |
Hong Kong Taoist
Association Tang Hin Memorial Secondary School |
6 |
School situated
within R(A) zone. |
6 |
B |
2 |
+7.7 |
Sheung Shui
Centre Block 1 |
30 |
R(A) |
30 |
B |
3 |
+8.8 |
Tong Wu Mansion,
Yuk Po Court |
30 |
R(A) |
30 |
B |
4 |
+7.7 |
Christian
Alliance Primary School |
6 |
G(IC) (Likely to
remain as school) |
6 |
B |
5 |
+8.9 |
Choi Ping House,
Choi Yuen Estate |
30 |
R(A) |
30 |
B |
6 |
+7.6 |
Low rise
commercial / residential building
at San Fung Avenue |
4 |
C/R |
4 |
B |
7 |
+9.2 |
Choi Pic
Mansion, Choi Po Court |
30 |
R(A) |
30 |
B |
8 |
+7.7 |
Low rise
commercial / residential
building on San Fung Avenue |
3 |
C/R |
3 |
B |
9 |
+9.2 |
Choi Ying
Mansion, Choi Po Court |
30 |
R(A) |
30 |
C |
10 |
+6.3 |
Village house at
Tai Tau Leng |
3 |
V |
3 |
B |
11 |
+6.1 |
Village house at
Tsung Pak Long |
3 |
V |
3 |
A |
12 |
+5.4 |
Tsung Pak Long
Village Primary School |
1 |
V |
1 |
A |
13 |
+5.9 |
Village House |
1 |
AGR |
3 |
A |
14 |
+5.5 |
Village House |
1 |
AGR |
3 |
A |
15 |
+6.5 |
Village house at
Ho Sheung Heung |
1 |
V |
3 |
A |
16 |
+6.4 |
Village House |
1 |
CDA |
3 (As detailed in
the OZP No. S/NE-KTN/3) |
B |
17 |
+7.9 |
Village House |
1 |
I(D) |
3 |
B |
18 |
+7.5 |
Village House |
1 |
OS |
1 |
B |
19 |
+13.1 |
Kindergarten |
1 |
G(IC) |
1 |
B |
21 |
+15.7 |
Village House |
2 |
OS |
3 |
B |
22 |
+18 |
Village House |
1 |
O |
1 |
B |
23 |
+23.1 |
Village House |
1 |
AGR |
1 |
B |
24 |
+17.7 |
Village House |
2 |
AGR |
2 |
B |
25 |
+12 |
Village House |
1 |
GB |
1 |
A |
26 |
+6.5 |
Village House |
2 |
GB |
2 |
A |
27 |
+6.7 |
Village House |
1 |
GB |
1 |
A |
28 |
+5.3 |
Village House |
1 |
U |
1 |
A |
29 |
+4.5 |
Village House |
1 |
U |
1 |
A |
30 |
+3.4 |
Village House |
1 |
U |
1 |
A |
31 |
+3.2 |
Village House |
1 |
CA |
1 |
A |
32 |
+3.2 |
Village House |
1 |
CA |
1 |
A |
33 |
+2.9 |
Village House |
2 |
CA |
2 |
A |
34 |
+8.0 |
Village House |
2 |
GB |
2 |
A |
35 |
+7.2 |
Village House |
1 |
U |
1 |
A |
* As
specified in the letter from Director of Environmental Protection dated 28 July
1999 Ref. EP2/G/A/101.
** RNSR
20 will be resumed for use as temporary works area
*** RNSRs
34 and 35 are used for assessing potential construction noise impact at Lok Ma
Chau Road only
R(A) Residential
Development Group A, high density, high rise
CDA Comprehensive
Development Area, can be commercial and residential, density medium
to
high
V Village.
Low rise, low density, often detached house.
O Open
Space
AGR Agricultural
OS Open
Storage
I(D) Industrial
Group D
GB Green
Belt
CA Conservation
Areas
U Unspecified
3.4 Construction Noise Assessment
3.4.1 This section presents the methodology, representative sensitive receivers, relevant assessment criteria, and up to date findings on the potential construction noise impact due to the development of the Spur Line. As the Main Drainage Channel Realignment Works at River Beas is expected to be largely complete by 2001 there will be no extensive cumulative construction noise impact with the Spur Line Project.
3.4.2 The only other concurrent infrastructure Project is the construction works for the San Tin Drainage Channel at Lok Ma Chau which is likely to start construction in 2002 to 2003. Based on the findings of the Final Report of the Environmental Impact Assessment for Main Drainage Channels and Poldered Village Protection Scheme for San Tin, NWNT, predicted construction noise levels of San Tin Channel construction are likely to range between 48~66 dB(A). In view of the low construction noise levels relative to the noise assessment criteria, the San Tin Drainage Channel project is not expected to cause a cumulative noise impact alongside the development of the Spur Line.
Assessment Methodology
3.4.3 The construction noise assessment was undertaken using the methodology given in the Technical Memorandum on Noise from Construction Works other than Percussive Piling of the NCO.
Construction Schedule and Equipment
3.4.4 Based on the project implementation programme dated 1 August 1999, the construction activities which are likely to result in potential noise impact will occur at the following times:
Table
3.2 Concurrent
Construction Activities under this Project Considered for Cumulative
Construction Noise Impact |
|||
|
|
|
|
Groups of Concurrent Activities |
Construction Activities |
Scheduled Time |
Representative Noise Sensitive Receivers Affected |
A |
Site formation for temporary works areas, new
permanent access roads, and Lok Ma Chau Terminus Hard rock removal at Pak Shek
Au Haul roads construction. |
February 2001 ~ February 2002 |
21, 22, 28, 29,
30 |
Lok Ma Chau
Terminus construction is over 500 m from any Representative Noise Sensitive
Receivers, and noise contribution from these activities is not significant |
Lok Ma Chau Terminus construction, which include: ·
Emergency
Vehicle Access (EVA) construction ·
Open
drainage channel. ·
Box
culvert. ·
Underground
sewage treatment works. ·
Retaining
structure. ·
Immigration
/ customs facilities. ·
Head wall. |
July 2001 ~ March 2004 |
N.A. |
|
Foot bridge link to Huanggang. |
February 2001 ~ February 2003 |
31 ~ 33 |
B |
West Section Alignment : Bore piling, pile cap
formation, column formation, viaduct deck installation |
March 2001 ~ January 2003 |
22 ~ 33 |
|
East Section Alignment : Bore piling, pile cap
formation, column formation, viaduct deck installation |
April 2001 ~ December 2002 |
13 ~ 19, 21 |
C This group is
only concurrent in February 2003 |
Improvement works to existing Sheung Shui Station,
and other ancillary structures such as footbridges, foot paths, and subways. |
February 2003 ~ July 2003 |
1 ~ 15 |
|
Water mains
diversion near Sheung Shui |
October 2000 ~ July 2003 (Only in winter when the mains are shut down) |
7 ~ 12 |
D |
Widening of Lok
Ma Chau Road as access road |
July 2001 - March 2004 |
34, 35 |
3.4.5 The likely type, quantity and the SWL for each type of Powered Mechanical Equipment (PME) used during the construction stage are listed in Table B1, Appendix B. It should be noted that an assumption has been made of the likely equipment to be used. The actual construction equipment will be determined by the contractors performing the works.
Assessment
Results
3.4.6 Table B.2 of Appendix B gives the unmitigated predicted noise levels for various construction activities. Table 3.3 gives a comparison of unmitigated predicted noise levels with noise assessment criteria.
Table 3.3
Comparison of Unmitigated and Mitigated Predicted Noise Levels with
Noise Criteria for RNSRs Potentially Affected by Construction Noise
Construction
Activity Group Considered |
Representative
Noise Sensitive Receivers (RNSRs) |
Distance from
Activities, m |
Unmitigated
Noise Levels at Worst Affected RNSRs (dB(A)) |
Exceed Noise
Assessment Criteria by : (dB(A)) |
Noise Reduction
due to Installation of Noise Barrier |
Mitigated Noise
Levels at Worst Affected RNSRs (dB(A)) |
Exceed Noise
Assessment Criteria by : (dB(A) |
||||
A1– Site Formation |
19 21 22 27 |
50 50 100 100 |
79 79 73 73 |
9 4 0 0 |
|
|
0 0 0 |
||||
A2– Hard Material
Removal |
21 22 23 24 |
50 25 80 15 |
77 83 73 87 (1st month) |
65 71 61 75 (2nd and 3rd
months) |
2 8 0 12 (1st month) |
0 0 0 0 (2nd and 3rd
months) |
|
(1st month) |
(2nd and 3rd
months) |
0
(1st month) |
0** 0 0
(2nd and 3rd
months) |
A3- Footbridge
Construction |
33 |
650 |
59 |
0 |
- |
59 |
0 |
||||
B (only noisiest
part of alignment construction presented) |
13 14 22 24 25 27 28 29 30 31 32 |
30 30 30 30 25 40 60 60 60 50 60 |
85 85 85 85
83 79 79 79 81 79 |
10 10 10 10
8 4 4 4 6 4 |
|
|
|
||||
C |
2 3 5 6 |
52 45 60 50 |
|
|
|
|
0 |
||||
D (Part 1) |
34 35 |
20 15 |
|
6 8 |
|
|
|
||||
* Noise
assessment criteria for schools is 70 dB(A) between 0700~2300 during
non-examination period.
** Screening
effect of topography dominates, additional benefit of temporary noise barrier
not significant.
3.4.7 When material is removed from cutting, excavation will begin at the top of existing ground level, progressing downwards until the desired invert level is reached. Then excavation will be carried out horizontally along the railway alignment. The top of the existing ground is approximately +26.0 mPD while that of the desired invert level is approximately +20.0 mPD. The equipment will be completely screened from the line of sight of the affected sensitive receivers represented by RNSRs 21, 22 and 24 one month after the excavation begins. It will remain out of sight for the next two months until excavation is completed. A 12 dB reduction is assumed, to take into account the screening effect of the topography one month into this activity.
3.4.8
During viaduct alignment construction, there will
also be exceedance of the ANLs at a number of
NSRs in the eastern section of the alignment. However, based on experience in
West Rail fFoundations, pilecap and pier construction , these
activities in Spur Line are not expected to affect any one single NSR in the vianity
vicinity
of 13, 4, 22, 24 and
25 for more than 1 month. The noisy activities of concern care the concrete delivery and
concreteing activities, including use of the vibratory poker. These activities will
take place for relatively short periods during the overall construction period
for the viaduct piers. Similarly, the excavation works
related to widening of Lok Ma Chau Road will exceed the ANL by 5dB(A). The
length of time for which this activity will impact NSR 35 is expected to be
less than a month.
3.4.9
From the noise assessment results,
potential construction noise impacts are expected at the following RNSRs (shown in Table 3.4):. Mitigation means
measures
are proposed to minimize the potential impact from noisey activities and to minimize the time for which NSRs
are exposed to these activities.
Table 3.4
RNSRs Potentially Affected by Construction Noise
Construction Activity |
Representative Noise Sensitive Receivers Affected by
Unmitigated Impact |
Site Formation |
19, 21 |
Widening of Lok Ma Chau Road |
34,35 |
Hard material removal from Pak Shek Au Cutting |
21, 22, 24 |
Construction of Alignment |
13, 14 |
|
22, 24, 27, 28,
29, 30, 31, 32 |
Improvement Works on Existing Sheung Shui Station
and Water Mains Diversion |
2, 3, 5 |
Mitigation
Measures
3.4.10
The following direct
alternative mitigation measures, as listed in Section 6 Annex 13 of the
TM EIAO had
beenwere
considered but were found to be inappropriate for mitigating the potential
construction noise impact.:
(a)alternative
land use arrangement: the project does not involve any proposed land use change
and there can be no change to planned use of the railway reserve.
(a)alternative
siting: the railway is not a planned noise sensitive land use.
(a)screening
by noise tolerant buildings: buildings development is not part of this Project.
(a)setback
of buildings: construction noise impacts affect existing buildings which cannot
be setback.
(a)decking
over: buildings development is not part of this Project. Existing buildings
cannot be used to deck over the proposed railway.
(a)Extended
podium: buildings development is not part of this Project. Existing podiums
cannot be used to deck over the proposed railway.
(a)building
orientation: buildings development is not part of this Project.
(a)treatment
of source: the Contractor is advised to use silenced or super silenced
equipment when ever applicable.
(a)alternative
alignment: this is discussed in Chapters 1 and 2 of this report.
(a)Noise
barrier / enclosure: considered. Mobile plant.
(a)special
buildings design: buildings development is not part of this Project.
(a)architectural
features / balcony: buildings development is not part of this Project.
(a)Open-textured
road surfacing: not relevant to construction noise.
3.4.11 The following measures are proposed for the reduction of potential noise impact:
(i)
Temporary noise barriers should be installed at active parts of
construction areas where construction equipment is being operated. The barriers
shall be constructed of solid material, without gaps, and of density no less
than 10 kg/m². These barriers should be designed to screen all operating
construction equipment from the line of sight of the RNSRs (At least 2.5 m tall).
This is expected to provide a 75 dB reduction.
(ii) Use of quiet equipment with proper maintenance and orientating equipment exhaust away from RNSRs.
(iii) When construction works are carried out close to schools, the schools should be notified in advance. Examination periods should be avoided when construction works are carried out near schools.
(iv) Reduction of powered and mechanical construction equipment as far as practicable.
Residual
Impacts
3.4.12 The residual impacts following the implementation of the proposed mitigation measures are given in Tables 3.3 and 3.5.
3.4.13
During site formation, installation of
a temporary noise barrier will reduce the noise level from the works to a level
of 2 4 dB(A) above the
acceptable criteria at RNSR 19. This exceedance will last for 2 to 3 weeks.
During the first month of hard material removal from Pak Shek Au Cutting, noise
assessment criteria would still be exceeded by 2dB(A) at RNSR 21, by 13 dB(A) at RNSR 22 and 57 dB(A) at RNSR 24 after
installation of a temporary noise barrier. RNSRs 21, 22 and 24 represent 3 and 4a total of 810 dwellings respectively.
The exceedance could last up to one month, after which the operating equipment
would be screened by topography. A number of 12 dwellings will be affected by the alignment
construction, however, the noisy activities considered involved in construction of foundations, pile capping and pier construction is are not likely to affect each NSR individually for more than 1 month. Three Four dwellings would be
affected by noise from the widening of Lok Ma Chau Road for 2 to 3 weeks.
Table 3.5
Representative Noise
Sensitive Receivers Affected by Residual Impact
Construction Activity |
Representative Noise Sensitive Receivers Affected by
Residual Impact |
Duration of Potential Residual Impact |
Site
Formation |
19
( |
2
to 3 weeks |
Hard
material removal from Pak Shek Au Cutting |
21, 22, 24 ( |
1
month |
Alignment Construction |
13, 14, 22, 24, 25 and 31 (1 to
7dB(A) above criteria) |
Less than 1 month at each NSR |
Widening
of Lok Ma Chau Road |
34, 35 ( |
2
to 3 weeks |
Monitoring
and Audit Requirements
3.4.14 Regular monitoring and auditing of construction noise at RNSR 19 during site formation of the adjacent temporary works area, and RNSRs 22 and 24 during hard material removal from Pak Shek Au Cutting and is recommended. Detailed requirements are given in Chapter 12. Ad-hoc monitoring and audit should also be carried out at RNSR 35 in case of complaints, and measures taken to ensure acceptable noise levels are met as far as possible.
Summary
3.4.15 Based on up to date information on the likely construction programme and the activities to be carried out, the potential construction noise impact was predicted. The provision of a solid temporary noise barrier of a minimum height of 2.5 m around active parts of the construction site and the reduction of noisy equipment during alignment construction are recommended to reduce potential noise impact.
3.4.16
Following the installation of these
measures 1 kindergarten will be affected by a noise level 24 dB above noise
assessment criteria for a period of 2 to 3 weeks, 7810 dwellings would be
affected by hard material removal at Pak Shek Au. The construction noise impact
would cause a residual impact of up to 13 to 57 dB(A) after mitigation for the first
month. Thereafter the activity would be screened from sight of these receivers
by topography. A number of 12 dwellings would be affected by pier construction
activities up to 7 dB(A) above the ANL, however, the time period of exceedance
would be less than one month, given the native
nature
and length of time for
noisy activities. 3Four dwellings would be affected by 13 to 5 dB above assessment
criteria for 2 to 3 weeks due to the widening of Lok Ma Chau Road.
3.4.17 Regular monitoring and audit of construction noise during hard material removal from Pak Shek Au cutting is recommended for RNSRs 22 and 24, during site formation of adjacent temporary works area monitoring is required at RNSR 19 and ad hoc monitoring and audit at RNSR 35 should be carried out if complaints arise.
3.5 Operational Noise Assessment
3.5.1 This section presents the methodology, sensitive receivers, relevant assessment criteria, and up to date findings on the potential operational noise impact due to Spur Line and other concurrent projects.
3.5.2 Sources of potential noise impact during operation phase of Spur Line include:
(i) railway
noise, which has three major components:
• airborne
noise originating from the propulsion system and wheel / rail interaction;
• structure
radiated or re-radiated noise resulting from wheel / rail interaction which is
transmitted through the viaduct structure;
• noise
from the air conditioner on the top of the carriage.
(ii) noise from fixed
plant located at railway stations, such as ventilation equipment and sewage
treatment works for the station, and any standby generators, and the proposed
standby transformer located at the existing Fanling Station electrical
transformer.
Fixed
Plant Operation Noise
3.5.3 The fixed and semi-fixed noise sources of the Spur Line during operation phrase include the following equipment:
•
Ventilation fans, dosing pumps, sewage pumps and motors from the
proposed Sewage Treatment Works (STW) for the Lok Ma Chau Station.
•
Ventilation fans, transformers, air handling units, emergency generators
and chillers of the Lok Ma Chau Station.
•
Standby emergency generator at the Sheung Shui Station.
3.5.4 The treatment process of the STW at Lo Wu is expected to be similar to that proposed at the Lok Ma Chau Station, although the capacity of the STW at Lo Wu is greater than that of the one planned at Lok Ma Chau.
3.5.5 At this stage the layout of STW, locations of generator and ventilation equipment and chillers have not been fixed. Design noise limits for each group of equipment, to meet the assessment criteria of ANLs - 5 dB(A), are proposed under this EIA.
3.5.6 The RNSRs worst affected by each type of noise source listed above, their corresponding ASRs, ANLs in dB(A) and values of ANLs - 5 dB(A), and their respective distances from the future noise sources are shown in Table 3.6.
Table 3.6
Details of RNSRs Worst
Affected by the Fixed Noise Sources Planned
Under the Spur Line
Project
Group and Location of Fixed Sources |
Worst Affected RNSRs |
ASR |
ANLs, dB(A) (ANLs at 23:00 to 07:00 is assumed to
be limiting) |
ANLs - 5, Leq (30 min) dB(A) |
Slant Distance Between Worst Affected RNSRs and
Fixed Noise Source, m |
Proposed Sewage
Treatment Works (STW) at Lok Ma
Chau Station |
33 |
A |
50 |
45 |
520 |
Ventilation
fans, transformers, air handling units, emergency generators and chillers at
Lok Ma Chau Station |
33 |
A |
50 |
45 |
520 |
Standby
emergency generator at the Sheung Shui Station |
2 |
B |
55 |
50 |
30 |
3.5.7 The design noise limits of the equipment are calculated according to standard acoustic principles. A +3 dB(A) correction is subtracted from the maximum allowable noise levels to account for facade reflection.
3.5.8 Table 3.7 gives the designed noise limits as sound pressure levels measured at 1 m from any exits/entrances of the specified plant room for each group of planned fixed sources to meet the target of ANL -5 dB(A) at the worst affected NSRs .
Table 3.7
Designed Noise limits for
Each Group of Planned Fixed Sources
Group and Location of Fixed Sources |
Design Noise limits, dB(A) |
Assumptions Made |
Proposed Sewage
Treatment Works (STW) at Lok Ma Chau Station |
104 |
+ 3 dB(A) facade correction. |
Ventilation
fans, transformers, air handling units, emergency generators and chillers at
Lok Ma Chau Station |
104 |
+ 3 dB(A) facade correction. |
Standby
emergency generator at the Sheung Shui Station |
85 |
+ 3 dB(A) facade correction. |
Railway
Noise Impact Assessment
Introduction
3.5.9 Noise emitted from the operation of railway on an at-grade, ballasted track is dominated by the airborne noise from the propulsion system wheel / rail interaction and the roof-mounted air conditioning (A/C) system. Trains moving on viaduct will excite vibration of the viaduct structure. This vibration is then re-radiated as noise. Trains operating on railway tracks on viaduct will therefore emit structure radiated noise in addition to the two types of airborne noise mentioned above.
3.5.10 The noise impacts that are likely to arise from the operation of the Spur Line have been assessed using detailed prediction methodologies agreed with the Environmental Protection Department (EPD). Assessment procedures include considerations of the Technical Memorandum on Environmental Impact Assessment Process and the Hong Kong Planning Standards and Guidelines (HKPSG) .
3.5.11 The objectives of the railway noise assessment are:
• to predict and evaluate the potential noise impact of railway operation at the RNSRs against railway noise assessment criteria;
• to identify, where noise assessment criteria is exceeded, appropriate technical or operational mitigation requirements and measures for airborne and structure re-radiated noise respectively;
• to predict and evaluate the acceptability of the residual noise impact following the implementation of the proposed mitigation measures against railway noise assessment criteria and recommendations for conditions which require consideration during detailed design stage as necessary.
Prediction Methodology
3.5.12 For the purpose of noise assessment, the beginning of the Spur Line is taken to be the switch points of the (future) turnouts from East Rail. The chainages of these switchpoints are CH 30660 and CH 30160 for the up and down tracks, respectively. Both tracks of the Spur line begin on short sections of ballast through the turnouts before rising onto viaducts to cross the adjacent nullah. The difference in chainages results in a short section of track (from CH 30160 to CH 30660) over which noise arises from the downtrack Spur Line train, but no noise arises for the uptrack train (as this train starts from a higher chainage). The noise assessment was carried out for all identified representative NSRs affected by Spur Line track only, from these defined chainages. The rail track to the south of these chainages is existing East Rail and is not therefore taken into account in the Spur Line assessment.
3.5.13 Potential railway operation noise impact at the identified RNSRs was predicted using a methodology agreed with EPD and based on methods used in the West Rail Final EIA Report[4] and procedures in the Calculation of Railway Noise 1995 (CRN) published by the UK Department of Transport.
3.5.14 In terms of noise from the interaction of wheels and rails, the following factors affect the predicted noise levels:
• type of rolling stock;
• train speed - the rolling noise increases with train speed;
• type of track and rail support structures - rolling noise levels differ as trains pass over different types of track, such as jointed or continuously welded tracks as well as structures such as bridges or viaducts.
3.5.15 The rail noise level at the RNSR was predicted by modelling the train as a line source. The noise level emanating from a moving train was predicted taking into account the noise attenuation due to distance, corrections for angle of view, screening effects from barriers and the facade reflection effect.
3.5.16 In predicting the noise from the railway, the track was divided into segments, the lengths of which are determined by factors such as train speed, curvature of the track and gradient. Each segment is then treated as a separate line source and the noise contribution from each segment is summed to obtain the predicted noise level at the RNSR. The major wayside noise component, namely airborne noise, structure radiated noise and A/C noise, were modelled separately and combined to obtain the predicted rail noise level.
3.5.17 Following agreement with EPD, a 20-metre segment length was adopted in the railway noise prediction. The track centre co-ordinates for both the up and down tracks of the Spur Line which were provided by KCRC at 20m intervals, were used in the prediction model.
3.5.18 The positions of these major noise sources along the alignment, namely airborne noise, structure radiated noise and A/C noise, as well as the top of the standard 1.2m parapet wall on the viaduct were calculated from these co-ordinates. The horizontal offsets from track centres and vertical offsets from top of rails adopted in estimating the noise source locations are tabulated in Table 3.8.
Offsets adopted in
Estimating Noise Source Location
Noise Source |
Horizontal Offset, m |
Vertical Offset, m |
Outboard Plenum Gap |
1.625 |
0.98 |
Inboard Plenum Gap |
-1.625 |
0.98 |
Structure-radiated Noise
(Standard Viaduct) |
0 |
-2 |
Structure-radiated Noise (At‑grade Plenum) |
0 |
2.08 |
A/C Noise |
0 |
3.74 |
Standard 1.2m parapet wall |
3.3 |
2.08 |
3.5.19 The maximum speed limit along the Spur Line is 100 km/h. The speed profiles for the proposed alignment (both up and down tracks) provided by KCRC were used to determine the train speed for each 20m track segment.
3.5.20 The source noise level in Lmax, of a train passby event at 100 km/h, 25 m from track centreline, and an elevation level with rail head was adjusted for speed, distance and angle of view, to obtain Lmax level at each RNSR. The noise contribution from each segment in terms of Equivalent Noise Level, Leq (30 min) at each RNSR, was calculated by applying barrier attenuation and façade effect correction. Source terms under different operating conditions are discussed in Section 3.5.26 to 3.5.33.
3.5.21 The predicted noise level at the RNSR was obtained by summing the contribution from all track segments. The railway noise calculation procedure, including equations used, is detailed in Appendix D. The reference viaduct noise spectrum used in estimating the barrier attenuation was adapted from the West Rail EIA study and is shown in Figure D.1.
Unmitigated Railway Noise Levels
Baseline Railway Operation Conditions
3.5.22
To determine unmitigated noise levels,
it was assumed that ballasted track will be used for the at-grade sections. Low
Vibration Track (LVT) is assumed on viaducts. The first Spur Line train will
depart from Sheung Shui Station at 0600 hours each day and the last train from
Lok Ma Chau Terminus one hour following the close of the Border Control
Point.at 12:30
a.m.
3.5.23 The worst-case scenario in terms of railway noise assumes an ultimate train frequency of 12 unskirted trains per hour in each direction during 0700 to 2300 hours (referred to as daytime). For the restricted night time period between 2300 to 0700 hour (referred to as nighttime), the train frequency is assumed to be reduced to 6 trains per hour per direction.
3.5.24 The viaduct sections will be incorporated with the plenum noise reduction system, and a 1.2m parapet wall above the walkway will be part of the standard viaduct design.
3.5.25 As the existing East Rail refurbished trains to be operated on the Spur Line are not equipped with vehicular skirts and under-car absorption, the airborne attenuation will be provided mainly by the under-walkway (single) plenum and the parapet wall.
Source Noise Levels
Wheel / Rail Noise
3.5.26 The refurbished trains operating on the existing KCRC East Rail will be used on the Spur Line. As such, the train noise source term assumed in this assessment has been obtained from wayside measurements conducted by AEC on the East Rail Mid Life Refurbished EMUs. This reference (airborne) noise source level on the at grade, ballasted track section is 86.3dB(A) in LmAmax 1.2 m above the ground, at 25 m from the nearest track centreline for a 12 car transit train travelling at-grade at 100 km/h. This is applied to the section just north of the Sheung Shui Station as well as the embankment and cutting section at Kwu Tung.
3.5.27 On viaduct, the airborne noise reduction provided by the single plenum system was modelled using the computer ray-tracing model, "RAYNOISE Rev. 3.0" by Numerical Integration Technologies. The noise attenuation provided by the 1.2m parapet wall was estimated based on an empirical approach developed by Makaewa[5].
3.5.28 The numerical modelling by RAYNOISE Rev. 3.0, based on the principles of geometrical acoustics, is utilised to predict the sound field produced by the sources and model the reflection from physical structures. The ray-tracing model was used to evaluate the effectiveness of the single plenum system. Determination of the total wayside noise for the viaduct sections is detailed in Appendix C. The attenuation provided by the viaduct plenum system for receptor located at 25m from track centreline, level with top of rail, is summarized in Table 3.9.
Attenuation provided by Single Plenum System
Plenum
Attenuation (250 mm gap), dB(A) |
Outboard
Side |
Inboard
Side |
11 |
11 |
3.5.29 The airborne source noise level for the viaduct sections with single plenum system is (Lmax) 75.3dB(A) for both the outboard and inboard side at 25m from track centreline for a train travelling at 100km/h.
Structure Radiated Noise
3.5.30 The structure radiated noise level of the viaduct section was provided by KCRC. The methodology used in the theoretical determination of the structure-radiated noise was detailed in the KCRC West Rail EIA Final Assessment Report.[6]
3.5.31 The structure radiated source noise level for the viaduct sections using Low Vibration Track (LVT) form is (Lmax) 66.5 dB(A) at 25m from track centreline for a train travelling at 100km/h (Appendix E, Table E1).
3.5.32 The structure radiated noise level for twin viaduct was applied for all viaduct structures along the route of the Spur Line for conservative assessment. The structure radiated noise source term was corrected to the reference speed of 100km/h for the Spur Line by assuming the variation in maximum structure radiated noise level with train speed is to follow a 25 log (speed) relationship.
3.5.33 The source A/C noise level of East Rail vehicles was derived from measurements taken at the Air Conditioner Workshop in the Maintenance Depot for the air-conditioning units installed on the East Rail trains[7]. The sound power level of the A/C unit was determined to be 110.9dB(A) which was subsequently input to the computer ray-tracing model, "RAYNOISE Rev. 3.0". The A/C source noise level was determined to be (Lmax) 62.8dB(A) at 25m from track centreline. KCRC confirmed that West Rail trains have a source A/C noise level of 57 dB(A) (Lmax) at 15 m from track centreline.
3.5.34
A complete set of noise source terms
used in the prediction of railway noise from Spur Line is shown in Appendix E. The
unmitigated noise levels were predicted based on the
standard viaduct design (walkway plenum, 1.2m parapet wall) with Low Vibration
Trackform.
3.5.35 The unmitigated noise levels were predicted based on the standard viaduct design (walkway plenum, 1.2m parapet wall) with Low Vibration Trackform. Comparison of the unmitigated noise levels in Leq (30minutes) at the RNSRs with the daytime and nighttime noise assessment criteria are given in Tables 3.10 and 3.11 respectively.
3.5.36
Within
the at-grade section at Sheung Shui, unmitigated noise levels at RNSR 6 exceeds
the respective daytime assessment criteria, and night time criteria are
exceeded at RNSRs 6 to 8 and 10 to 12. These RNSRs are affected by the railway
noise from the at-grade ballasted track section north of Sheung Shui Station.
The criteria were exceeded mainly due to the higher air borne noise emitted as
trains pass the points and crossings just north of the existing Sheung Shui
Station.
3.5.37 On the viaduct section, predicted unmitigated noise levels at RNSRs 13 and 14 exceed the daytime noise criteria. Night time criteria were exceeded at RNSRs 13 to 19. The Area Sensitivity Rating at these RNSRs is mostly ‘A’. These RNSRs are affected by potential noise from train movements on the viaduct section. Both airborne noise and structure radiated noise are significant causes of noise exceedance.
3.5.38 The highest noise levels for both daytime and night time are found at RNSRs 21 to 27 at Kwu Tung, where the RNSRs are situated close to the at grade embankment / cutting section of the alignment. Airborne noise is the only significant component of the potential noise impact for these locations. The exceedance is mainly due to the very short horizontal distances between the railway and these RNSRs. At the worst affected receiver, RNSR 25, the unmitigated LAeq (30minutes) is 76dB(A).
3.5.39 At RNSRs 28 to 33 along the viaduct leading towards the Lok Ma Chau Station, unmitigated noise levels are mostly below their respective daytime assessment criteria except for 2dB(A) exceedance at RNSR 28 and 1 dB(A) exceedance at RNSR 29. The night time unmitigated noise levels, however, were exceeded at all of these RNSRs.
Comparison of the Unmitigated Noise Levels for Railway Operation
between 0700~2300 hours and the Noise Assessment Criteria
RNSR |
Receiver
Setback Distance (m) |
Unmitigated
Noise Level, LAeq (30 minutes) dB(A) Between
0700~2300 |
Noise
Assessment Criteria for 0700
– 2300 hours, LAeq (30 minutes) dB(A) |
Exceedance
of Acceptable Noise Level, dB(A) 0700
– 2300 hours |
|
Up
Track |
Down
Track |
||||
|
|
|
|
|
|
1 |
264 |
265 |
49 |
65 |
0 |
2-1 |
145 |
144 |
50 |
65 |
0 |
2-2 |
147 |
145 |
50 |
65 |
0 |
2-3 |
153 |
152 |
50 |
65 |
0 |
3-1 |
81 |
84 |
51 |
65 |
0 |
3-2 |
74 |
77 |
51 |
65 |
0 |
3-3 |
81 |
83 |
Negligible* |
65 |
0 |
4 |
218 |
214 |
Negligible |
65 |
0 |
5 |
63 |
67 |
55 |
65 |
0 |
6-1 |
59 |
55 |
67 |
65 |
2 |
6-2 |
58 |
54 |
65 |
65 |
0 |
6-3 |
93 |
90 |
Negligible |
65 |
0 |
7-1 |
112 |
116 |
62 |
65 |
0 |
7-2 |
105 |
109 |
62 |
65 |
0 |
8 |
263 |
252 |
59 |
65 |
0 |
9-1 |
154 |
164 |
61 |
70 |
0 |
9-2 |
147 |
157 |
62 |
70 |
0 |
10-1 |
249 |
260 |
60 |
65 |
0 |
10-2 |
249 |
260 |
59 |
65 |
0 |
11 |
376 |
394 |
59 |
60 |
0 |
12-1 |
388 |
409 |
57 |
60 |
0 |
12-2 |
394 |
416 |
58 |
60 |
0 |
13-1 |
22 |
28 |
64 |
60 |
4 |
13-2 |
15 |
19 |
62 |
60 |
2 |
14-1 |
22 |
27 |
63 |
60 |
3 |
14-2 |
24 |
29 |
62 |
60 |
2 |
15-1 |
189 |
184 |
59 |
60 |
0 |
15-2 |
193 |
188 |
57 |
60 |
0 |
16 |
72 |
67 |
61 |
65 |
0 |
17-1 |
25 |
29 |
63 |
65 |
0 |
17-2 |
23 |
28 |
62 |
65 |
0 |
18-1 |
32 |
26 |
63 |
65 |
0 |
18-2 |
36 |
32 |
61 |
65 |
0 |
19-1 |
67 |
71 |
63 |
65 |
0 |
19-2 |
68 |
73 |
63 |
65 |
0 |
21-1 |
71 |
67 |
71 |
65 |
6 |
21-2 |
69 |
64 |
72 |
65 |
7 |
22-1 |
32 |
36 |
75 |
65 |
10 |
22-2 |
36 |
40 |
73 |
65 |
8 |
23-1 |
72 |
77 |
71 |
65 |
6 |
23-2 |
89 |
94 |
71 |
65 |
6 |
24-1 |
27 |
32 |
75 |
65 |
10 |
24-2 |
23 |
28 |
76 |
65 |
11 |
25-1 |
27 |
22 |
76 |
60 |
16 |
25-2 |
15 |
10 |
74 |
60 |
14 |
26 |
96 |
101 |
70 |
60 |
10 |
27 |
45 |
41 |
73 |
60 |
13 |
28 |
59 |
54 |
62 |
60 |
2 |
29-1 |
64 |
60 |
61 |
60 |
1 |
29-2 |
68 |
63 |
61 |
60 |
1 |
30-1 |
67 |
62 |
59 |
60 |
0 |
30-2 |
67 |
62 |
59 |
60 |
0 |
31-1 |
48 |
43 |
57 |
60 |
0 |
31-2 |
44 |
40 |
59 |
60 |
0 |
32-1 |
63 |
58 |
56 |
60 |
0 |
32-2 |
59 |
54 |
58 |
60 |
0 |
33 |
115 |
111 |
58 |
60 |
0 |
* Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
Table 3.11
Comparison of the
Unmitigated Noise Levels for Railway Operation
between 2300~0700 hours
and the Noise Assessment Criteria
RNSR |
Receiver
Setback Distance (m) |
Unmitigated
Noise Level, LAeq (30 minutes) dB(A) Between
2300~0700 |
Noise Assessment Criteria, for 2300
– 0700 hours LAeq
(30 minutes) dB(A) |
Exceedance
of Acceptable Noise Level, dB(A) 2300
- 0700 hours |
|
Up
Track |
Down
Track |
||||
|
|
|
|
|
|
1 |
264 |
265 |
46 |
55 |
0 |
2-1 |
145 |
144 |
47 |
55 |
0 |
2-2 |
147 |
145 |
47 |
55 |
0 |
2-3 |
153 |
152 |
47 |
55 |
0 |
3-1 |
81 |
84 |
48 |
55 |
0 |
3-2 |
74 |
77 |
48 |
55 |
0 |
3-3 |
81 |
83 |
Negligible* |
55 |
0 |
4 |
218 |
214 |
Negligible |
55 |
0 |
5 |
63 |
67 |
52 |
55 |
0 |
6-1 |
59 |
55 |
64 |
55 |
9 |
6-2 |
58 |
54 |
62 |
55 |
7 |
6-3 |
93 |
90 |
Negligible |
55 |
0 |
7-1 |
112 |
116 |
59 |
55 |
4 |
7-2 |
105 |
109 |
59 |
55 |
4 |
8 |
263 |
252 |
56 |
55 |
1 |
9-1 |
154 |
164 |
58 |
60 |
0 |
9-2 |
147 |
157 |
59 |
60 |
0 |
10-1 |
249 |
260 |
57 |
55 |
2 |
10-2 |
249 |
260 |
56 |
55 |
1 |
11 |
376 |
394 |
56 |
50 |
6 |
12-1 |
388 |
409 |
54 |
50 |
4 |
12-2 |
394 |
416 |
55 |
50 |
5 |
13-1 |
22 |
28 |
61 |
50 |
6 |
13-2 |
15 |
19 |
59 |
50 |
9 |
14-1 |
22 |
27 |
60 |
50 |
10 |
14-2 |
24 |
29 |
60 |
50 |
10 |
15-1 |
189 |
184 |
56 |
50 |
6 |
15-2 |
193 |
188 |
54 |
50 |
4 |
16 |
72 |
67 |
58 |
55 |
3 |
17-1 |
25 |
29 |
60 |
55 |
5 |
17-2 |
23 |
28 |
59 |
55 |
4 |
18-1 |
32 |
26 |
60 |
55 |
5 |
18-2 |
36 |
32 |
58 |
55 |
3 |
19-1 |
67 |
71 |
60 |
55 |
5 |
19-2 |
68 |
73 |
60 |
55 |
5 |
21-1 |
71 |
67 |
68 |
55 |
13 |
21-2 |
69 |
64 |
69 |
55 |
14 |
22-1 |
32 |
36 |
72 |
55 |
17 |
22-2 |
36 |
40 |
70 |
55 |
15 |
23-1 |
72 |
77 |
68 |
55 |
13 |
23-2 |
89 |
94 |
68 |
55 |
13 |
24-1 |
27 |
32 |
72 |
55 |
17 |
24-2 |
23 |
28 |
73 |
55 |
18 |
25-1 |
27 |
22 |
73 |
50 |
23 |
25-2 |
15 |
10 |
71 |
50 |
21 |
26 |
96 |
101 |
67 |
50 |
17 |
27 |
45 |
41 |
70 |
50 |
20 |
28 |
59 |
54 |
59 |
50 |
9 |
29-1 |
64 |
60 |
58 |
50 |
8 |
29-2 |
68 |
63 |
58 |
50 |
8 |
30-1 |
67 |
62 |
56 |
50 |
6 |
30-2 |
67 |
62 |
56 |
50 |
6 |
31-1 |
48 |
43 |
54 |
50 |
4 |
31-2 |
44 |
40 |
56 |
50 |
6 |
32-1 |
63 |
58 |
53 |
50 |
3 |
32-2 |
59 |
54 |
55 |
50 |
5 |
33 |
115 |
111 |
55 |
50 |
5 |
* Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.40 The unmitigated Lmax level at the RNSRs are compared against the HKPSG noise criterion as tabulated in Table 3.12. Only at RNSRs 22, 24 and 25 are the HKPSG standards exceeded.
Comparison of the Unmitigated Levels
with Noise Assessment Criteria for LAmax
RNSR |
Receiver
Setback Distance (m) |
Maximum
Predicted Noise Level, LAmax (30 minutes), dB(A) |
Exceedance
of L Amax Criterion of 85dB(A) for 2300-0700 hours |
|
Up
Track |
Down
Track |
|||
|
|
|
|
|
1 |
264 |
265 |
50 |
0 |
2-1 |
145 |
144 |
53 |
0 |
2-2 |
147 |
145 |
53 |
0 |
2-3 |
153 |
152 |
53 |
0 |
3-1 |
81 |
84 |
54 |
0 |
3-2 |
74 |
77 |
54 |
0 |
3-3 |
81 |
83 |
Negligible* |
- |
4 |
218 |
214 |
Negligible |
- |
5 |
63 |
67 |
60 |
0 |
6-1 |
59 |
55 |
75 |
0 |
6-2 |
58 |
54 |
74 |
0 |
6-3 |
93 |
90 |
Negligible |
- |
7-1 |
112 |
116 |
69 |
0 |
7-2 |
105 |
109 |
70 |
0 |
8 |
263 |
252 |
65 |
0 |
9-1 |
154 |
164 |
69 |
0 |
9-2 |
147 |
157 |
69 |
0 |
10-1 |
249 |
260 |
65 |
0 |
10-2 |
249 |
260 |
65 |
0 |
11 |
376 |
394 |
64 |
0 |
12-1 |
388 |
409 |
63 |
0 |
12-2 |
394 |
416 |
64 |
0 |
13-1 |
22 |
28 |
75 |
0 |
13-2 |
15 |
19 |
72 |
0 |
14-1 |
22 |
27 |
73 |
0 |
14-2 |
24 |
29 |
73 |
0 |
15-1 |
189 |
184 |
66 |
0 |
15-2 |
193 |
188 |
65 |
0 |
16 |
72 |
67 |
70 |
0 |
17-1 |
25 |
29 |
73 |
0 |
17-2 |
23 |
28 |
73 |
0 |
18-1 |
32 |
26 |
73 |
0 |
18-2 |
36 |
32 |
72 |
0 |
19-1 |
67 |
71 |
72 |
0 |
19-2 |
68 |
73 |
73 |
0 |
21-1 |
71 |
67 |
81 |
0 |
21-2 |
69 |
64 |
82 |
0 |
22-1 |
32 |
36 |
86 |
1 |
22-2 |
36 |
40 |
84 |
0 |
23-1 |
72 |
77 |
81 |
0 |
23-2 |
89 |
94 |
80 |
0 |
24-1 |
27 |
32 |
86 |
1 |
24-2 |
23 |
28 |
87 |
2 |
25-1 |
27 |
22 |
87 |
2 |
25-2 |
15 |
10 |
85 |
0 |
26 |
96 |
101 |
80 |
0 |
27 |
45 |
41 |
84 |
0 |
28 |
59 |
54 |
72 |
0 |
29-1 |
64 |
60 |
71 |
0 |
29-2 |
68 |
63 |
70 |
0 |
30-1 |
67 |
62 |
68 |
0 |
30-2 |
67 |
62 |
68 |
0 |
31-1 |
48 |
43 |
66 |
0 |
31-2 |
44 |
40 |
67 |
0 |
32-1 |
63 |
58 |
65 |
0 |
32-2 |
59 |
54 |
66 |
0 |
33 |
115 |
111 |
65 |
0 |
·
* Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.41 Details of the breakdown of unmitigated noise levels for each RNSR are given in Appendix E.
Proposed Mitigation Measures and Residual
Noise Impact
3.5.42 To mitigate the potential railway noise impact, KCRC is committed to the following mitigation:
• KCRC will adopt the multi-plenum system developed for West Rail on the viaduct section. In addition, track-forms will include the use of Floating Slab Track (FST), Low Vibration Track (LVT) and resilient base plates as appropriate. In areas where there is potential for development, i.e. Kwu Tung SGA, viaduct design will allow for the provision of additional noise mitigation measures, if necessary. On the at-grade section, KCRC will adopt the single-plenum system with ballasted track. In the future, if development proposals require it, additional noise mitigation measures could be retrofitted.
3.5.43 By committing to these measures for the operation hours most sensitive to noise, a similar level of noise attenuation will be achieved on the Spur Line as on West Rail.
3.5.44 A full noise enclosure is proposed at a Chainage of approximately 30+024 to 30+184. Sound absorption treatment on the interior surface of the enclosure will be required to prevent reverberant noise breakout from tunnel portals.
3.5.45 A 200 m long, 2 m tall sound absorptive track side noise barrier at the up track side, 4.5 m from the track centreline, is proposed between Chainage 30+680 and 30+880, to provide additional screening of the airborne noise for RNSRs 11 and 12. The height of this proposed barrier is measured from the future ground level. This section of the alignment is located on a slope climbing from the at grade section just north of the Sheung Shui Station towards the viaduct section.
3.5.46 Figure 3.1 (1 and 2 of 5) presents the locations of the proposed enclosure and the noise barrier.
3.5.47 FST will be adopted on the viaduct section from Sheung Shui to the beginning of the cutting/embankment section at Kwu Tung to reduce the vibration transmitted to the viaduct structure, thereby mitigating the structure-radiated noise so as to achieve wayside noise compliance. This will ensure the structure radiated noise level will not affect potential developments within Kwu Tung SGA.
3.5.48 LVT will be adopted on the viaduct section from the end of the cutting/embankment section at Kwu Tung to the Lok Ma Chau Terminus. Based on the planned village and conservation area land uses, this level of mitigation will be sufficient for potential future development between Pak Shek Au and Lok Ma Chau Terminus. Details of the performance of LVT are provided in Appendix E.
3.5.49 To mitigate airborne noise, a standard viaduct design with a parapet extending to 1.2 m above safety walkway will be adopted for all viaduct sections. This feature will enable the incorporation of the multi-plenum noise reduction system.
3.5.50 Near Kwu Tung area, due to the close proximity of the track from RNSRs 21 to 27, airborne noise is predicted to be responsible for the exceedance of daytime and nighttime noise assessment criteria.
3.5.51 The standard walkway deck structure which allows the incorporation of a sound reduction single plenum system is proposed along all of the at-grade, cutting / embankment section of the Spur Line alignment, between Chainages 33+050 to 34+660.
3.5.52 Since this section of the alignment is entirely at-grade, structure radiated noise is negligible. As a result there are no design constraints on track form at this section in terms of noise criteria compliance. Where ballasted track is retained, the incorporation of a walkway deck must take into consideration maintenance requirements of the ballast.
Prediction of Mitigated Noise Level
3.5.53 The following sections describe the conditions under which the mitigated noise levels (residual noise impact) have been calculated.
Operation
Between 0700 ~ 2300
• twelve East Rail refurbished, un-skirted trains will be operated in each direction per hour. Top speed is 100 km/h;
• the noise source terms with respect to A/C noise is 62.8 dB(A) as an Lmax at 25m from track centreline;
• noise source terms for ballasted track (airborne only) just north of Sheung Shui Station is 86.3dB(A) in Lmax at 25m from track centreline for a train travelling at 100km/h;
• structure radiated noise source term for all viaduct sections after installation of FST is 58.5dB(A) as an Lmax at 25m from track centreline for a train travelling at 100km/h, assuming a baseplate static stiffness of 13kN/mm;
• airborne noise source term for all viaduct sections with single noise reduction plenum associated with un-skirted trains is 75.3dB(A) (Lmax) for both the inboard and the outboard at 25m from track centreline for a train travelling at 100km/h.
Operation Between 0600 ~ 0700 and After 2300
• six skirted trains will be operated in each direction per hour. Top speed is also 100 km/h;
•
the noise source terms
with respect to A/C noise is 57
dB(A) as an Lmax at 15 m from track centreline;
•
noise source terms for ballasted
track (airborne only) just north of Sheung Shui Station is 80.6 dB(A)*. 80.6dB(A) was derived
from a sense
source term
of 82.1 dB(A) for the new KCRC transit trains, and the addition of a skirt
along the length of the car as part of the multi-pleasure plenum noise alternation attenuation system. More
details are provided in Appendix E as an Lmax at 25m from track
centreline for a train travelling at 100 km/h;
• structure radiated noise source term for all viaduct sections after installation of FST is 58.5dB(A) as an Lmax at 25m from track centreline for a train travelling at 100km/h, assuming a baseplate static stiffness of 13kN/mm;
• airborne noise source term for all viaduct sections with the multi-plenum noise reduction system associated with skirted trains is 69.0 dB(A) (Lmax) at 25m from track centreline for a train travelling at 100km/h for both the outboard side and the inboard side.
* 80.6 dB(A) was derived from a sense source term of 82.1 dB(A) for the new
KCRC transit trains, and the addition of a skirt along the length of the car as part of
the multi-plenum noise
alternation attenuation system. More details are provided
in Appendix E.
It should be noted that the criterion for six skirted trains during the first hour of operation (0600 to 0700) was used of the purposes of this assessment. This provides sufficient noise reduction at RNSRs to meet the NCO criteria. Consideration is being given to the cost-effectiveness of adding additional mitigation in certain key sections of the alignment, to allow the use of unskirted trains during this hour and still meet NCO criteria.
Further breakdowns of source terms levels under different types of operating conditions are given in Appendix E.
3.5.54 With the incorporation of the above mitigation measures, the predicted mitigated noise levels predicted at all RNSRs were below their respective daytime noise assessment criteria. The mitigated daytime noise levels at the RNSRs are compared against their respective noise assessment criteria in Table 3.13.
Table 3.13
Comparison of the
Mitigated Noise Levels for Railway Operation
between 0700~2300 hours
and the Noise Assessment Criteria
RNSR |
Receiver
Setback Distance (m) |
Maximum
Predicted Noise Level, dB(A) LAeq
(30 minutes) |
Noise
Assessment Criteria, for 0700
– 2300 hours LAeq
(30 minutes) dB(A) |
Exceedance
of Acceptable Noise Level, dB(A) 0700
– 2300 hours |
|
Up
Track |
Down
Track |
||||
|
|
|
|
|
|
1 |
264 |
265 |
43 |
65 |
0 |
2-1 |
145 |
144 |
44 |
65 |
0 |
2-2 |
147 |
145 |
44 |
65 |
0 |
2-3 |
153 |
152 |
44 |
65 |
0 |
3-1 |
81 |
84 |
46 |
65 |
0 |
3-2 |
74 |
77 |
46 |
65 |
0 |
3-3 |
81 |
83 |
Negligible* |
65 |
0 |
4 |
218 |
214 |
Negligible |
65 |
0 |
5 |
63 |
67 |
50 |
65 |
0 |
6-1 |
59 |
55 |
61 |
65 |
0 |
6-2 |
58 |
54 |
58 |
65 |
0 |
6-3 |
93 |
90 |
Negligible |
65 |
0 |
7-1 |
112 |
116 |
57 |
65 |
0 |
7-2 |
105 |
109 |
58 |
65 |
0 |
8 |
263 |
252 |
57 |
65 |
0 |
9-1 |
154 |
164 |
60 |
70 |
0 |
9-2 |
147 |
157 |
60 |
70 |
0 |
10-1 |
249 |
260 |
58 |
65 |
0 |
10-2 |
249 |
260 |
57 |
65 |
0 |
11 |
376 |
394 |
57 |
60 |
0 |
12-1 |
388 |
409 |
54 |
60 |
0 |
12-2 |
394 |
416 |
56 |
60 |
0 |
13-1 |
22 |
28 |
58 |
60 |
0 |
13-2 |
15 |
19 |
56 |
60 |
0 |
14-1 |
22 |
27 |
51 |
60 |
0 |
14-2 |
24 |
29 |
53 |
60 |
0 |
15-1 |
189 |
184 |
49 |
60 |
0 |
15-2 |
193 |
188 |
48 |
60 |
0 |
16 |
72 |
67 |
50 |
65 |
0 |
17-1 |
25 |
29 |
51 |
65 |
0 |
17-2 |
23 |
28 |
51 |
65 |
0 |
18-1 |
32 |
26 |
51 |
65 |
0 |
18-2 |
36 |
32 |
50 |
65 |
0 |
19-1 |
67 |
71 |
50 |
65 |
0 |
19-2 |
68 |
73 |
51 |
65 |
0 |
21-1 |
71 |
67 |
48 |
65 |
0 |
21-2 |
69 |
64 |
49 |
65 |
0 |
22-1 |
32 |
36 |
52 |
65 |
0 |
22-2 |
36 |
40 |
50 |
65 |
0 |
23-1 |
72 |
77 |
51 |
65 |
0 |
Table 3.13 (cont’d)
Comparison of the
Mitigated Noise Levels for Railway Operation
between 0700~2300 hours
and the Noise Assessment Criteria
RNSR |
Receiver
Setback Distance (m) |
Maximum
Predicted Noise Level, dB(A) LAeq
(30 minutes) |
Noise
Assessment Criteria, for 0700
– 2300 hours LAeq
(30 minutes) dB(A) |
Exceedance
of Acceptable Noise Level, dB(A) 0700
– 2300 hours |
|
Up
Track |
Down
Track |
||||
|
|
|
|
|
|
23-2 |
89 |
94 |
51 |
65 |
0 |
24-1 |
27 |
32 |
52 |
65 |
0 |
24-2 |
23 |
28 |
53 |
65 |
0 |
25-1 |
27 |
22 |
52 |
60 |
0 |
25-2 |
15 |
10 |
50 |
60 |
0 |
26 |
96 |
101 |
49 |
60 |
0 |
27 |
45 |
41 |
51 |
60 |
0 |
28 |
59 |
54 |
55 |
60 |
0 |
29-1 |
64 |
60 |
54 |
60 |
0 |
29-2 |
68 |
63 |
54 |
60 |
0 |
30-1 |
67 |
62 |
54 |
60 |
0 |
30-2 |
67 |
62 |
53 |
60 |
0 |
31-1 |
48 |
43 |
52 |
60 |
0 |
31-2 |
44 |
40 |
53 |
60 |
0 |
32-1 |
63 |
58 |
51 |
60 |
0 |
32-2 |
59 |
54 |
52 |
60 |
0 |
33 |
115 |
111 |
51 |
60 |
0 |
* Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.55 For nighttime operation, the mitigated nighttime noise levels at each RNSR are compared against their respective noise assessment criteria as shown in Table 3.14. The mitigated Leq (30 minute) noise levels are below their respective noise assessment criteria at all receivers.
Comparison of the Mitigated Noise Levels for Railway Operation
between 2300~0700 hours and the Noise Assessment Criteria
RNSR |
Receiver
Setback Distance (m) |
Mitigated
Noise Level, dB(A) LAeq
(30 minutes) between 2300~0700 hours |
Noise
Assessment Criteria, for 2300
- 0700 hours LAeq
(30 minutes) dB(A) |
Exceedance
of Acceptable Noise Level, dB(A) 2300
– 0700 hours |
|
Up
Track |
Down
Track |
||||
|
|
|
|
|
|
1 |
264 |
265 |
35 |
55 |
0 |
2-1 |
145 |
144 |
38 |
55 |
0 |
2-2 |
147 |
145 |
38 |
55 |
0 |
2-3 |
153 |
152 |
38 |
55 |
0 |
3-1 |
81 |
84 |
38 |
55 |
0 |
3-2 |
74 |
77 |
37 |
55 |
0 |
3-3 |
81 |
83 |
Negligible* |
55 |
0 |
4 |
218 |
214 |
Negligible |
55 |
0 |
5 |
63 |
67 |
41 |
55 |
0 |
6-1 |
59 |
55 |
49 |
55 |
0 |
6-2 |
58 |
54 |
46 |
55 |
0 |
6-3 |
93 |
90 |
Negligible |
55 |
0 |
7-1 |
112 |
116 |
49 |
55 |
0 |
7-2 |
105 |
109 |
49 |
55 |
0 |
8 |
263 |
252 |
48 |
55 |
0 |
9-1 |
154 |
164 |
51 |
60 |
0 |
9-2 |
147 |
157 |
52 |
60 |
0 |
10-1 |
249 |
260 |
49 |
55 |
0 |
10-2 |
249 |
260 |
49 |
55 |
0 |
11 |
376 |
394 |
48 |
50 |
0 |
12-1 |
388 |
409 |
46 |
50 |
0 |
12-2 |
394 |
416 |
47 |
50 |
0 |
13-1 |
22 |
28 |
49 |
50 |
0 |
13-2 |
15 |
19 |
47 |
50 |
0 |
14-1 |
22 |
27 |
45 |
50 |
0 |
14-2 |
24 |
29 |
47 |
50 |
0 |
15-1 |
189 |
184 |
41 |
50 |
0 |
15-2 |
193 |
188 |
40 |
50 |
0 |
16 |
72 |
67 |
43 |
55 |
0 |
17-1 |
25 |
29 |
46 |
55 |
0 |
17-2 |
23 |
28 |
45 |
55 |
0 |
18-1 |
32 |
26 |
45 |
55 |
0 |
18-2 |
36 |
32 |
44 |
55 |
0 |
19-1 |
67 |
71 |
43 |
55 |
0 |
19-2 |
68 |
73 |
44 |
55 |
0 |
21-1 |
71 |
67 |
40 |
55 |
0 |
21-2 |
69 |
64 |
41 |
55 |
0 |
22-1 |
32 |
36 |
43 |
55 |
0 |
Table 3.14 (Cont’d)
Comparison of the Mitigated Noise Levels for
Railway Operation
between 2300~0700 hours and the Noise Assessment
Criteria
RNSR |
Receiver Setback Distance (m) |
Mitigated Noise Level, dB(A) LAeq (30 minutes)
between 2300~0700 hours |
Noise Assessment Criteria, for 2300 - 0700 hours LAeq (30 minutes) dB(A) |
Exceedance of Acceptable Noise
Level, dB(A) 2300 – 0700 hours |
|
Up Track |
Down Track |
||||
|
|
|
|
|
|
22-2 |
36 |
40 |
42 |
55 |
0 |
23-1 |
72 |
77 |
42 |
55 |
0 |
23-2 |
89 |
94 |
43 |
55 |
0 |
24-1 |
27 |
32 |
43 |
55 |
0 |
24-2 |
23 |
28 |
45 |
55 |
0 |
25-1 |
27 |
22 |
43 |
50 |
0 |
26 |
96 |
101 |
41 |
50 |
0 |
27 |
45 |
41 |
43 |
50 |
0 |
28 |
59 |
54 |
50 |
50 |
0 |
29-1 |
64 |
60 |
50 |
50 |
0 |
29-2 |
68 |
63 |
49 |
50 |
0 |
30-1 |
67 |
62 |
50 |
50 |
0 |
30-2 |
67 |
62 |
49 |
50 |
0 |
31-1 |
48 |
43 |
48 |
50 |
0 |
31-2 |
44 |
40 |
49 |
50 |
0 |
32-1 |
63 |
58 |
47 |
50 |
0 |
32-2 |
59 |
54 |
48 |
50 |
0 |
33 |
115 |
111 |
46 |
50 |
0 |
* Negligible indicates
that this facade has no angle of view towards Spur Line and therefore does not
contribute to the total noise level. These NSR facades were selected for the
assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.56 With the proposed mitigation incorporated, the mitigated Lmax levels at all RNSRs are within the noise criterion of 85dB(A) as an Lmax for railway noise between 2300~0700. The mitigated Lmax levels are compared with the criterion in Table 3.15.
Comparison of the Mitigated Levels (LAmax) for Railway
Operation
between 2300~0700 hours with Noise Assessment Criterion
RNSR |
Receiver
Setback Distance (m) |
Mitigated
LAmax Level, dB(A) Operation
Between 2300~0700 |
Exceed
85 dB(A) in LAmax By: (dB(A)) |
|
Up
Track |
Down
Track |
|||
|
|
|
|
|
1 |
264 |
265 |
41 |
0 |
2-1 |
145 |
144 |
44 |
0 |
2-2 |
147 |
145 |
44 |
0 |
2-3 |
153 |
152 |
44 |
0 |
3-1 |
81 |
84 |
45 |
0 |
3-2 |
74 |
77 |
44 |
0 |
3-3 |
81 |
83 |
Negligible* |
0 |
4 |
218 |
214 |
Negligible |
0 |
5 |
63 |
67 |
50 |
0 |
6-1 |
59 |
55 |
61 |
0 |
6-2 |
58 |
54 |
58 |
0 |
6-3 |
93 |
90 |
Negligible |
0 |
7-1 |
112 |
116 |
59 |
0 |
7-2 |
105 |
109 |
60 |
0 |
8 |
263 |
252 |
58 |
0 |
9-1 |
154 |
164 |
61 |
0 |
9-2 |
147 |
157 |
62 |
0 |
10-1 |
249 |
260 |
58 |
0 |
10-2 |
249 |
260 |
58 |
0 |
11 |
376 |
394 |
56 |
0 |
12-1 |
388 |
409 |
55 |
0 |
12-2 |
394 |
416 |
56 |
0 |
13-1 |
22 |
28 |
63 |
0 |
13-2 |
15 |
19 |
60 |
0 |
14-1 |
22 |
27 |
59 |
0 |
14-2 |
24 |
29 |
60 |
0 |
15-1 |
189 |
184 |
51 |
0 |
15-2 |
193 |
188 |
50 |
0 |
16 |
72 |
67 |
56 |
0 |
17-1 |
25 |
29 |
60 |
0 |
17-2 |
23 |
28 |
60 |
0 |
18-1 |
32 |
26 |
59 |
0 |
18-2 |
36 |
32 |
58 |
0 |
19-1 |
67 |
71 |
56 |
0 |
19-2 |
68 |
73 |
56 |
0 |
21-1 |
71 |
67 |
52 |
0 |
Table 3.15 (Cont’d)
Comparison of the Mitigated Levels (LAmax)
for Railway Operation
between 2300~0700 hours with Noise Assessment
Criterion
RNSR |
Receiver
Setback Distance (m) |
Mitigated
LAmax Level, dB(A) Operation
Between 2300~0700 |
Exceed
85 dB(A) in LAmax By: (dB(A)) |
|
Up
Track |
Down
Track |
|||
|
|
|
|
|
21-2 |
69 |
64 |
53 |
0 |
22-1 |
32 |
36 |
57 |
0 |
22-2 |
36 |
40 |
55 |
0 |
23-1 |
72 |
77 |
55 |
0 |
23-2 |
89 |
94 |
55 |
0 |
24-1 |
27 |
32 |
56 |
0 |
24-2 |
23 |
28 |
58 |
0 |
25-1 |
27 |
22 |
57 |
0 |
25-2 |
15 |
10 |
55 |
0 |
26 |
96 |
101 |
52 |
0 |
27 |
45 |
41 |
56 |
0 |
28 |
59 |
54 |
64 |
0 |
29-1 |
64 |
60 |
63 |
0 |
29-2 |
68 |
63 |
62 |
0 |
30-1 |
67 |
62 |
63 |
0 |
30-2 |
67 |
62 |
62 |
0 |
31-1 |
48 |
43 |
61 |
0 |
31-2 |
44 |
40 |
62 |
0 |
32-1 |
63 |
58 |
59 |
0 |
32-2 |
59 |
54 |
60 |
0 |
33 |
115 |
111 |
57 |
0 |
* Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.57 Detailed railway noise prediction results for all RNSRs are given in Appendix E.
Provisions for Planning Noise Sensitive
Land Uses in Future
3.5.58 The mitigation measures described in the above sections are sufficient for the reduction of the potential railway noise impact to an acceptable level, at all the existing and confirmed future noise sensitive receivers currently known within the EIA Study Area.
3.5.59 In line with the commitment given to Government by KCRC, the railway and viaduct structure will be designed with provision for additional noise mitigation, if necessary, in future potential development areas.
3.5.60
This section provides estimates of noise impacts
from KCRC Spur Line train operations on the planned high-rise residential
property development located within the Kwu Tung North SGA at the minimum
setback provided by the Consultants of the Planning Department and Territory Development Department.
The currently proposed location and layout of the Kwu Tung North SGA is shown
in Figure 3.2. According to the information provided,
high rise structures will be located no closer than 10 m setback on the north
side and 35 m setback on the south side of the railway reserve, which is 84
m wide, centred on the midline of the planned Spur Line alignment throughout
the SGA. This indicates a minimum
setback of 52 m to the residential towers measured from the viaduct centre. The building heights are assumed to have
a maximum height of 140 m (43 storeys), including podium heights. The height
from ground to top of rail is assumed to be 7 m.
3.5.61 At this setback, the wayside noise level, where there is line of sight from the plenum gap (between the walkways and the train) and the receiver located in the residential tower, is completely determined by airborne noise. The structure borne and A/C noise are low enough relative to the airborne noise to allow these nosie sources to be neglected. The minimum distance between source and receiver located along line of sight is 54 m for the far track and 57 m for the near track. Assuming two simultaneous (skirted) train passbys at 76 kph, and these minimum distances, an upper bound for the expected noise level (LAeq30) obtained for either the at-grade or viaduct track sections is 55 dB(A). The calculation is summarised in Table 3.16 below.
Table 3.167
Calculation of the Maximum Noise Impact on Receivers located
in high rise residential towers located at the minimum setback of 10 m
outside the Railway Reserve
|
FORMULA/COMMENT |
NEAR TRACK dB(A) |
FAR TRACK dB(A) |
AIRBORNE SOURCE LEVEL |
AT 100 kph AND 25 m SETBACK |
69 |
69 |
DISTANCE CORRECTION |
10Log(d/25); d = 54 m FAR TRACK, d = 57 m NEAR TRACK |
-3.6 |
-3.3 |
SPEED CORRECTION |
30Log(76/100) |
-3.6 |
-3.6 |
CORRECTION FROM LAmax to LAeq30 |
6 TRAINS PER HOUR PER DIRECTION |
-13 |
-13 |
FAÇADE CORRECTION |
--- |
3 |
3 |
WAYSIDE NOISE LEVEL FROM EACH TRAIN (LAeq30) |
--- |
51.8 |
52.1 |
3.5.62 As the SGA will have an Area Sensitivity Rating B, the night time maximum allowable noise limit (LAeq30) is 55 dB(A). Therefore, assuming a maximum speed of 76 kph along the track adjacent to the SGA, no additional mitigation beyond that already specified will be required to satisfy the NCO requirement.
3.5.63 As a worst case scenario, if development was carried out (contrary to the minimum setback and maximum building height proposed by the Planning Department) so that residential towers were to be placed at the boundary of the railway reserve, the minimum setback between source and receiver would be reduced by 10m. Compliance with the night time maximum allowable noise limit (LAeq30) of 55 dB(A) could then be achieved by one of two measures:
1. Further reduction of maximum speed on the track adjacent to the SGA to 71 kph with no additional mitigation beyond that already specified; or
2. No restriction on train speed (up to 90 kph) but additional edge wall barriers, up to full enclosure, placed atop the parapet between the train tracks and the noise sensitive receiver, with sufficient height to block line-of-sight between the under walkway plenum gap (near track only) and the receiver.
3.5.64
Similar to the situation described above, an area
south of the railway track has recently been zoned CDA and is included in the latest OZP. The location
of the nearest block is the same distance from the railway reserve as quoted above (10m
from the railway reserve, 52m from the centre line of the track) and the
maximum height of the blocks will be similar to that quoted for the SGA (140m
including the podium). The noise levels for the worst care scenario will be
similar to those calculated for the SGA, although this location has the advantage of being at-grade ballast which will provide additional noise alternation attenuation through ballast absorption.
Similar mitigation measures are recommended as for the SGA i.e. a reduction in
train speed in this section of the alignment, to achieve the nighttime NCO criteria of 55 dB(A).
Cumulative
Impacts
3.5.65 The significance of cumulative noise impacts from Spur Line and East Rail train operations were evaluated. The same principles were assumed in the rail noise calculation, as for the Spur Line noise assessment. As night-time has the strictest noise criteria, night-time noise levels were calculated for
(i) spur Line with and without mitigation;
(ii) existing East Rail noises levels; and
(iii) for the reduced noise levels expected for East Rail as a result of Spur Line mitigation.
3.5.66 The number of trains operated on the Spur Line during nighttime hours is 6 per direction per hour (as used in calculation of the Spur Line noise levels earlier). For the cumulative noise level calculation, an additional 6 trains per direction per hour travelling on East Rail from Sheung Shui to Lo Wu were included. As described previously, the start of the Spur Line is taken to be the start of the ballasted section incorporating the two turnouts for the up and down tracks. South of the downtrack turnout (CH 30160), a total of 12 East Rail trains will be travelling per direction per hour on ballasted track. These trains are unskirted and have a noise source term of 86.3dB(A)).
3.5.67 Between the turnout for the down track and the turnout for the up track (the stretch of track between CH 30160 and 30660), the combination of trains will change. Along this section of track, there are 3 tracks. Of the 12 trains per direction per hour travelling on the track (i.e. 24 trains in total), 12 trains will be travelling on the western most track (6 going to Lo Wu and 6 going onto the up track of Spur Line (skirted)), 6 trains will be on the middle tack (coming from Lo Wu) and 6 (skirted) trains will be Spur Line trains, coming towards Sheung Shui station on the down track of the Spur Line. Spur Line trains will be skirted and have a corresponding noise source term on ballasted track of 80.6dB(A).
3.5.68 At CH 30660, where the turnout for the up track for the Spur Line starts, the combination of trains changes to 6 Spur Line skirted trains on viaduct and 6 unskirted East Rail trains on ballast.
3.5.69
These criteria were used in modeling
the noise levels at selected worst case NSRs, which would be impacted to the
greatest extent by East Rail, Spur Line or a combination of both. The calculated noise levels for Spur
Line train operation (with and without proposed mitigation) and East Rail noise
levels (without Spur Line i.e. existing conditions, and with the mitigation
proposed for Spur Line) are shown in the table below.
Table 3.178
Summary of Cumulative Impact
Results
Reduction in East Rail Noise
Levels due to Spur Line and
Relative Impact of East Rail and
Spur Line on Cumulative Noise Levels
(Night-time Noise Levels)
RNSR ID |
Existing East Rail |
Mitigated East Rail |
Mitigated Spur Line |
Difference between Cumulative Noise (East Rail & Spur Line,
both mitigated) and Mitigated East Rail |
Difference between Mitigated East Rail and Existing East Rail |
1 |
70 |
67 |
35 |
0.0 |
-3 |
2,1 |
66 |
64 |
38 |
0.0 |
-2 |
2,2 |
68 |
66 |
38 |
0.0 |
-2 |
2,3 |
68 |
66 |
38 |
0.0 |
-2 |
3,1 |
59 |
55 |
38 |
0.1 |
-4 |
Table 3.187 (Cont’d)
Summary of Cumulative Impact
Results
Reduction in East Rail Noise
Levels due to Spur Line and
Relative Impact of East Rail and
Spur Line on Cumulative Noise Levels
(Night-time Noise Levels)
RNSR ID |
Existing East Rail |
Mitigated East Rail |
Mitigated Spur Line |
Difference between Cumulative Noise (East Rail & Spur Line,
both mitigated) and Mitigated East Rail |
Difference between Mitigated East Rail and Existing East Rail |
3,2 |
65 |
63 |
37 |
0.0 |
-2 |
3,3 |
66 |
64 |
Negligible |
0.0 |
-2 |
4 |
59 |
57 |
Negligible |
0.0 |
-2 |
5 |
66 |
60 |
41 |
0.1 |
-6 |
6,1 |
70 |
61 |
49 |
0.3 |
-10 |
6,2 |
71 |
58 |
46 |
0.3 |
-13 |
6,3 |
63 |
51 |
Negligible |
0.0 |
-11 |
7,1 |
67 |
58 |
49 |
0.5 |
-9 |
7,2 |
67 |
58 |
49 |
0.6 |
-10 |
8 |
64 |
61 |
48 |
0.3 |
-3 |
9,1 |
65 |
61 |
51 |
0.4 |
-4 |
9,2 |
66 |
62 |
52 |
0.3 |
-4 |
10,1 |
64 |
62 |
49 |
0.2 |
-3 |
10,2 |
64 |
62 |
49 |
0.2 |
-3 |
11 |
64 |
62 |
48 |
0.2 |
-2 |
12,1 |
64 |
62 |
47 |
0.2 |
-2 |
12,2 |
62 |
60 |
46 |
0.2 |
-3 |
13,1 |
66 |
64 |
47 |
0.1 |
-3 |
13,2 |
66 |
63 |
49 |
0.2 |
-3 |
14,1 |
62 |
60 |
47 |
0.2 |
-3 |
14,2 |
60 |
57 |
45 |
0.3 |
-3 |
15,1 |
53 |
51 |
41 |
0.5 |
-3 |
15,2 |
57 |
54 |
40 |
0.2 |
-3 |
Notes: (1) All values are LAeq
(30 minutes)
(2) Existing East
Rail is in the absence of Spur Line
(3) Mitigated East
Rail is with Spur Line mitigation (enclosure and barrier) implemented
(4) Mitigated Spur
Line is with mitigation (enclosure and barrier) in place to meet NCO
requirements
(5) Cumulative Noise
is mitigated East Rail and mitigated Spur Line summed. In subtracting mitigated East Rail, the
relative contribution of Spur Line to the Cumulative Noise Level is shown.
(6) Subtracting
mitigated East Rail from Existing East Rail shows the reduction in noise levels
due to Spur Line mitigation
(7) Negligible
indicates that this facade has no angle of view towards Spur Line and therefore
does not contribute to the total noise level. These NSR facades were selected
for the assessment of cumulative noise impacts (see Section on Cumulative Noise
Impacts).
3.5.70Three main conclusions are drawn from the results of the cumulative impacts assessment.
1. The existing East Rail operation noise level is much higher than the noise level achieved for the Spur Line operation. For several of the NSRs, the difference between the mitigated Spur line noise level and the existing East Rail operational noise level is over 10dB(A)
2. Given the large difference between the noise levels for the Spur Line and existing East Rail trains, any additional mitigation proposed for the Spur Line would not produce a perceptible change in the cumulative noise level.
3. The mitigation measures that have been proposed for the Spur Line have a positive effect on reducing the noise level for the existing East Rail trains. For example, at NSR5, the noise level contributed by the existing East Rail operation is 66dB(A). This is reduced to 60dB(A) through the incorporation of the noise enclosure to cover the turnout north of Sheung Shui station, implemented as part of the Spur Line scheme.
3.5.71 In summary, the implementation of mitigation under the Spur Line scheme has a positive effect on reducing noise levels for the existing East Rail train operation and the maximum mitigation has been incorporated in the Spur Line design to minimize cumulative impacts.
Summary
3.5.72 Based on noise levels of East Rail refurbished trains, ultimate railway operation frequency, ballasted track for at grade section and LVT for viaduct section, unmitigated noise levels due to the railway operation of the Spur Line were predicted for each RNSR. For the at grade section, wheel /rail and A/C noise are the main components of potential airborne noise.
3.5.73 The daytime and nighttime noise assessment criteria were exceeded at many of these RNSRs due to their location close to the railway alignment, and the predominance of rural or semi-rural environment in the Study Area, which leads to an ASR associated with the most stringent noise criteria for railway noise.
3.5.74 To mitigate the potential railway operation noise to an acceptable level, the following mitigation measures are proposed.
•
For operation between 0600 and 0700 (beginning of
traffic peak)and
after 2300 when noise criteria are most stringent, six skirted trains
will be operated in each direction per hour. Consideration is being given to
the provision of additional mitigation measures at key locations, which would
allow for operation of unskirted East Rail trains during this hour.
• Full enclosure over points and crossings just north of the Sheung Shui Station is proposed to mitigate the airborne noise at the high rise RNSRs found near Sheung Shui Station.
• A 200 m long, 2 m tall sound absorptive noise barrier will be used for additional screening of airborne noise for RNSRs 11 and 12.
• FST will be installed for viaduct sections between Sheung Shui and Kwu Tung. LVT will be used on other viaduct sections.
• A standard viaduct design with a parapet extending to 1.2 m above the safety walkway will be adopted on all viaduct sections;
• The standard viaduct design, in which a safety walkway is installed on side and median walls, will be adopted on the at-grade ballasted embankment/cutting section west of Kwu Tung.
3.5.75 Following the implementation of the above mitigation measures the residual noise at RNSRs will meet both the daytime and nighttime noise assessment criteria.
3.5.76 In the absence of a defined layout for Kwu Tung SGA, noise levels have been calculated at distances indicated by Planning Department. Mitigation may be required for those NSRs close to the railway reserve, in the form of reduced train speed or additional barriers/enclosures.
3.5.77 Cumulative impacts from Spur Line and the existing East Rail were evaluated to examine the relative impact from each rail operation. The existing East Rail operation has a significantly higher noise level than that arising from Spur line operation. Mitigation which has been incorporated into the Spur Line design minimizes the impact from Spur Line on cumulative noise levels, and also has a positive effect of reducing noise levels from the existing East Rail operation.
3.6 Conclusions
3.6.1
Potential noise impact due to
construction activities, railway operation and electrical/mechanical equipment
at Lok Ma Chau Station were predicted for the RNSRs identified. Short term
construction noise impact exceeding criteria by 1 to 57 dB(A) is expected at
approximately 1126 noise sensitive receivers after implementation
of all practicable mitigation measures. The maximum period of exeedance at any
one RNSR will be 1 month. Regular and ad-hoc monitoring and audit programme was
proposed for these affected receivers. Design noise limits were proposed for
the electrical and mechanical plant located at Lok Ma Chau Terminus to ensure
Noise Control Ordinance criteria are complied with during plant operation.
3.6.2 To mitigate railway noise impacts to an acceptable level, the following mitigation measures have been proposed.
• Full enclosure over a crossing just north of Sheung Shui Station.
• A 200 m long, 2 m tall noise barrier north of Tsung Pak Long.
• FST to be installed on viaduct sections between Sheung Shui and Kwu Tung.
• LVT to be installed on the western viaduct section i.e. west of the embankment section at Chau Tau, through to Lok Ma Chau Terminus.
•
Train service to be provided by six
skirted trains to operate in each direction per hour between 0600~0700, and during any one hour after
2300 when the noise criteria is the most stringent when the beginning of
the traffic peak hour coincides with the most stringent noise criteria for many
RNSRs. Consideration is being given to the provision of additional noise
mitigation in key areas to allow for operation of unskirted East Rail trains
during this hour.
• Standard viaduct design with a parapet extending to 1.2 m above the safety walkway to be installed at all viaduct sections.
• Standard viaduct design with a parapet extending to 1.2 m above the safety walkway on at-grade ballasted cutting/embankment section west of Kwu Tung.
• Within areas planned for residential or other noise sensitive uses in the Kwu Tung SGA, the railway will be designed to allow for additional noise mitigation if this is required in the future.
3.6.3 Consideration of future development along Spur Line, in particular Kwu Tung SGA, indicates that, for sensitive receivers close to the railway reserve, some mitigation may be required in the form of reduced train speed or additional barriers/enclosures.
3.6.4 Assessment of cumulative impacts indicates that the existing East Rail operation has a significantly higher noise level (more than 10 dB(A) higher) than that arising from Spur line operation. Mitigation on Spur Line reduces the noise to a level which results in its contribution to the cumulative noise level being insignificant. Mitigation for Spur Line will also reduce noise levels on existing East Rail operation.
3.7
References
1 Technical Memorandum of Environmental Impact Assessment Process, 1997, Environmental Protection Department, Hong Kong Government
2 Environmental Impact Assessment Ordinance Cap. 499, 1997, Hong Kong Government
3
Hong
Kong Planning Standards and Guidelines, Planning Department, 1989, Hong Kong
Government
4 Hong Kong Town Planning Board, Town Planning Ordinance, Fanling / Sheung Shui - Outline Zoning Plan No. S/FSS/7
5 Hong Kong Town Planning Board, Town Planning Ordinance, Kwu Tung South - Outline Zoning Plan No. S/NE-KTS/4
6 Hong Kong Town Planning Board, Town Planning Ordinance, Kwu Tung North - Outline Zoning Plan No. S/NE-KTN/2
7 Hong Kong Town Planning Board, Town Planning Ordinance, San Tin - Outline Zoning Plan No. S/YL-ST/1
8 Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites, 2nd Edition, Environmental Protection Department, June 1997, Hong Kong Government
9 Noise survey conducted by KCRC (Mid Life Refurbished EMUs)
10 Nelson, P. M., "Transportation Noise Reference Book", Butterworths & Co. Ltd., 1987
11 Nelson, J. T., "Transit Cooperative Research Program Report 23 - Wheel/Rail Noise Control Manual", Transportation Research Board, National Research Council (1997) pp. 25-32
12 Saurenman, H. J., Nelson, J. T. and Wilson, G. P., "Handbook of Urban Rail Noise and Vibration Control", U.S. Department of Transportation, February 1982
13 Peters, S. " The Prediction of Railway Noise Profiles, " Journal of Sound Vibration, Vol. 32, No. 1 (1974) pp. 87-99
14 Crockett, A.R., Daroux, P.A. and Wilson G.P., "Concept Specification and Noise Evaluation of the Multi-Plenum Model for Train Noise Attenuation of the KCRC West Rail", Wilson, Ihrig & Associates prepared for ERM Hong Kong Ltd., December 1997
15 Marsden P. R., Pyke J. R. and Bullen R., " West Rail Initial and Final Assessment Report", Environmental Impact Assessment Contract TS900, ERM Hong Kong Ltd., prepared for Kowloon Canton Railway Corporation, January 1998
16 Beranek, L.L., Noise and Vibration Control, McGraw-Hill (1971)
17 American Society of Heating and Refrigeration Engineers, 1995 Applications Handbook
18 Maekawa, Z., Noise Reduction by Screens, Applied Acoustics (1) (1968)
19 Crockett, A.R. and Wilson G.P., "Concept Specification and Structure Radiated Noise Evaluation of the KCRC West Rail Viaduct", Wilson, Ihrig & Associates prepared for ERM Hong Kong Ltd., March 1998
20 Remington, P., "Wheel/Rail Rolling Noise, II : Validation of the Theory", J. Acoust. Soc. Am, 81(6), June 1987
21 Crockett, A. R. and Pyke, J. R., " Viaduct Design for Minimization of Direct and Structure Radiated Train Noise", presented at the International Workshop on Railway Noise (IWRN), November 1998
22 Noise Control on Construction and Open Sites, BS5228 : Part 1 : British Standards Institution, 1984
23 “A Guide to Measurement and Prediction of the Equivalent Continuous Sound Level”, UK Noise Advisory Council
24 Kurze, U.J. and G.S. Anderson, Sound Attenuation by Barriers, App. Acoustics (4), 1977
25 Allied Environmental Consultants Limited, "Noise Measurement Survey Report - Study of the Refurbished EMUs”, Issue 1, September 1998
26 Kowloon Canton Railway Corporation Preliminary Project Study Contract No. EA980020; Implementation Proposal to Government; Technical Report; Binnie-Meinhardt JV
[1] Annex 5, Table 1, Technical Memorandum of Environmental Impact Assessment Process, 1997, Environmental Protection Department, Hong Kong Government.
[2] Table 3, Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites, 2nd Edition, Environmental Protection Department, June 1997, Hong Kong Government.
[3] Table 3, Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites, 2nd Edition, Environmental Protection Department, June 1997, Hong Kong Government.
[4] Marsden P.R., Pyke J.R. and Bullen R. West Rail EIA Final Report (1998). ERM HK Ltd for KCRC.
[5] Leo L. Beranek, Noise and Vibration Control, pp 174-180, McGraw-Hill, 1988
[6] Marsden
P.R., Pyke J.R. and Bullen R. West Rail EIA Final Report (1998). ERM HK Ltd for
KCRC.
[7] KCRC East Rail Noise Control - New Fleet : Noise Measurement Survey Report by Allied Environmental Consultants Ltd, Issue 1, June 1998.