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The EIS has not recommended total enclosure for the Tsing Yi viaduct facing Cheung On Estate as the proposed 1.4m high barrier incorporating acoustically absorbent materials should be able to reduce the AR operating noise at Cheung On Estate to be within the legal criteria, i.e. 60 dB(A)Leq (30 min) under the Noise Control Ordinance.
In addition, MTRC has also reviewed the design of the turnback siding which had originally planned to be located at the viaduct opposite the West Cheung On Estate. It has now decided to move the alignment of this particular side trick (120m in total) away from the residential blocks(from A to B in the location map attached) and construct it in tunnel. This will further reduce the noise impacts on the West Cheung On Estate.
Apart from the above noise prevention measures, a number of other measures will be adopted for other parts of the western end of Tsing Yi Station. These will eventually include a cover over the upper railway tracks between Tsing Yi Station and Tsing King Road and an extended height barrier of 3.8m on the southern side of the viaduct nearest to St. Paul's village. In short, the noise impacts in respect of the AR design and construction have been and will continue to be closely monitored.
(b)
The Mass Transit Railway Corporation does not have a cost estimate nor an assessment of the effect of a total enclosure for the AR viaduct facing Cheung On Estate as there has been no need to utilise this measure in accordance with the EIS recommendation. It is also impossible to give a standard rate as each AR section is different. The long tunnel at one end and the Tsing Yi Station at the other would present significant ventilation problems if the design of total enclosure were to be adopted. Very approximately, the cost for the particular AR section involved would probably exceed HK$200 million.
It is impossible either to give a direct dollar per meter price for the design of a semi-enclosure, but the recommended 1.4m high absorptive barrier will be the most cost-effective solution for the Tsing Yi viaduct facing Cheung On Estate. According to the EIS, with this barrier in place, the AR operating noise at Cheung On Estate would be able to meet the legal requirement under the Noise Control Ordinance.