Construction of the Tung Chung Line Extension in Hong Kong has reached another milestone with the completion of the tunnel breakthrough in its West section. The works were undertaken by Bouygues Travaux Publics and Dragages Hong Kong in a joint venture.

A tunnel boring machine (TBM) named ‘Xihe’ was deployed to construct the tunnels extending from the existing Tung Chung Station to the future Tung Chung West Station. The machine has now concluded “its mission” following the successful breakthrough of the two tunnels in both directions, and the project will move into the track-laying and electrical and mechanical installation phase, shared MTR Corporation.

The use of TBM Xihe, featuring a diameter of approximately 7.3 m and weighing about 1,000 t, to excavate the tunnels effectively minimised the impact on the surrounding community, said MTR. The machine also installed precast tunnel lining segments simultaneously during excavation, significantly enhancing construction efficiency and safety. The TBM was launched in early 2025 and completed the tunnel towards Tung Chung West Station in October the same year.

MTR further highlighted one of the project’s challenges: overcoming space constraints at the Tung Chung West Station site by executing its first-ever in-place TBM U-turn operation. This innovative approach reduced the need for large-scale lifting and ground transportation before commencing excavation of the tunnel back towards Tung Chung Station.

“MTR is committed to building a community railway using a community-friendly approach. [TBM] Xihe has overcome complex and variable geological conditions, boring through mountains and beneath the sea to establish the underground railway corridor for the Tung Chung West section,” explained Jeny Yeung, CEO of MTR Corporation. “This breakthrough fully demonstrates the professionalism and strong collaboration of the project team. It would not have been possible without the understanding and support of the local community.”

Ms Yeung added that the Tung Chung Line Extension project is expected to be completed in 2029, after which it will further enhance the transport network and connectivity in North Lantau.

According to MTR, major track diversion works at the Tung Chung East section are currently underway, with the Hong Kong-bound track expected to be diverted in the third quarter of this year, allowing trains to operate on the new track section. Subsequently, a section of the existing tracks will be removed to make way for the Tung Chung-bound track diversion works, including the remaining two critical turnout installations to be carried out later this year and next year.

All images: MTR Corporation