How to formulate the railway alignment and decide between above-ground and underground scheme options?

When planning the railway alignment, we will carefully study details of the surrounding areas, such as the environment, topography, geology, population distribution, etc. We will also analyse the cost and benefits, constructability, potential impacts on nearby ecology and communities, land development requirements, implications on future railway extensions, operation and maintenance, etc., of different alignment options.

As for the above-ground or underground scheme options, both have their relative pros and cons, for example:

Scheme option / Factors in determining the scheme



Engineering considerations on understanding of geological conditions

Vary in different situations

Engineering considerations on construction techniques

Vary in different situations

Predictability of construction time

Relatively higher

Relatively lower

Impact on use and development of above-ground lands

Relatively more

Relatively less

Impact on environment, including surrounding ecology, especially for ecologically important sites

Relatively long-term

Relatively short-term

When formulating railway alignment, we will conduct studies on underground and above-ground scheme options and listen to the views from different stakeholders. After preliminary assessment and consideration of various factors, the underground scheme is considered as a sustainable option for the Northern Link and could actively respond to the opinions of stakeholders. We are now conducting further technical studies and design works based on the underground scheme option. The actual alignment and station locations of the Northern Link will be announced later.