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Factsheets, Plans and Map, Review Report

Fact Sheet - Airport Railway Extended Overrun Tunnel and North Hong Kong Island Line

Why we need to extend the Airport Railway Overrun Tunnel

- For safety reasons, an overrun tunnel of sufficient length is required at all terminal stations to ensure trains failing to stop at the design position, as a result of human error or defective equipment, would not collide with the tunnel end.

- The existing 84-metre overrun tunnel for the Airport Railway is acceptable for the current service level

- But, to enhance capacity, the existing overrun tunnel has to be extended by 40 metres as a matter of urgency.

- The MTRCL forecasts that the current overrun tunnel will only remain acceptable until 2006.

Why we need the Extended Portion of the Airport Railway Overrun Tunnel

- MTRCL needs a further extended portion of 460 metres to allow the Airport Railway and Tung Chung Line to operate at full design capacity.

- Both railways are forecast to reach full design capacity by 2014, but provision for the project must be made in CRIII.

- The full overrun tunnel will also allow for extensions into eastern Hong Kong Island as part of a proposed North Hong Kong Island Line.

Are there alternative alignments?

- No. The extended overrun tunnel has to link up with the existing overrun tunnel (to the west) and the proposed North Hong Kong Island Line (to the east). There is no reasonable alternative.

- The adopted alignment is already tucked as close to the existing shoreline as possible.

Why we need North Hong Kong Island Line (NIL)

- The NIL is a strategic rail link that will meet the long-term demand for mass transit services on Hong Kong Island beyond 2016. To ensure future construction is not jeopardized, there is a need to protect the alignment within the scope of CRIII work.

Are alternative alignments available?

- The NIL alignment is dictated by the Airport Railway Extended Overrun Tunnel to the west, the water channel of the Hong Kong Convention and Exhibition Centre (HKCEC) (the foundations of which were specifically designed for this purpose) and the existing Fortress Hill station to the east.

- The NIL alignment is already as close as possible to the existing shoreline. Any shift of the alignment inland would affect the foundations of the HKCEC.


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