The tunnel boring machine (TBM) Xihe has entered a new phase of excavation on Hong Kong’s Tung Chung Line Extension (TUE), commencing construction of the down-track tunnel towards the existing Tung Chung Station. This follows the successful completion of its first drive on the up-track tunnel linking the future Tung Chung West Station to the launch shaft.
The milestone represents a key step in delivering the twin-bore railway tunnels that will connect new stations at Tung Chung West and Tung Chung East to the existing MTR network, significantly improving transport capacity for the expanding Tung Chung New Town.
Tung Chung Line Extension: Expanding Rail Connectivity
The Tung Chung Line Extension forms part of Hong Kong’s long-term railway development strategy to support population growth and new urban development on Lantau Island. The project includes the construction of two new stations and approximately 1.3km of new twin railway tunnels, integrated with the existing operational line.
Construction works commenced in 2023 and, once completed, the extension will enhance accessibility, reduce journey times and support major residential and commercial developments in the area. The line is currently programmed for commissioning later in the decade.
TBM Xihe: Designed for Complex Ground Conditions
Xihe is a slurry shield TBM manufactured by Herrenknecht and purpose-built for the geological and hydrogeological conditions encountered along the Tung Chung alignment. The machine has a diameter of approximately 7.3m, an overall length of around 100m, and a total weight of close to 1,000 tonnes.
Following completion of the up-track tunnel drive, the TBM was turned underground using a push-pull arrangement combined with a self-propelled modular transporter. This approach eliminated the need to dismantle the machine or lift it to the surface, reducing programme time, minimising environmental impact and avoiding disruption to the surrounding urban area.
After undergoing inspection, maintenance and system checks, Xihe was relaunched from the Tung Chung West shaft to begin excavation of the down-track tunnel towards the existing railway infrastructure.
Managing Urban and Operational Constraints
Tunnel construction for the Tung Chung Line Extension is being carried out in a constrained environment, close to operating railway assets, residential developments and community facilities. Stringent controls are in place to manage ground movement and settlement, with continuous monitoring to safeguard nearby structures and ensure the uninterrupted operation of the existing Tung Chung Line.
The project team is deploying advanced tunnelling techniques, real-time instrumentation and robust risk management procedures to address the challenges associated with soft ground conditions and proximity to live infrastructure.
A Key Step Towards Completion
Completion of the down-track tunnel will mark a major milestone in the delivery of the twin-bore alignment. Once operational, the Tung Chung Line Extension will play a vital role in supporting sustainable development in North Lantau and strengthening Hong Kong’s overall rail network resilience. 02/26.
