Major underground tunnelling works connecting Terminal 2 and the future Terminal 5 at Changi Airport have been completed, Changi Airport Group announced on Dec 31, sharing more details about the large-scale engineering project.
The completed works involve three tunnels, each stretching 1.7km, built beneath one of the airport’s runways. Two of the tunnels are meant for passengers, while the third is designed for baggage transport. The passenger tunnels will be served by automated people movers, similar to the Skytrains currently operating at Changi Airport. According to the senior vice president of Changi East Construction, Dr Wen Dazhi, “(The) tunnels enable Changi Airport to operate as a single integrated airport.”
Boring works for the tunnels began in January 2022 and were completed by December that year. The full project later received certification in October 2024. One standout feature is the baggage tunnel, which has an excavated diameter of 12.3 metres. Dr Wen said it was “the biggest bored tunnel in Singapore at the time of construction.”
Challenges
One of the main challenges during construction was keeping surface disturbance to a minimum, especially since tunnelling was carried out beneath a live taxiway. Dr Wen explained that this was necessary to ensure airport operations were not affected while works were ongoing.
Although the main tunnelling works have been completed, additional construction is still underway to connect the tunnels to both terminals. At Terminal 2, a basement is currently being excavated to build a baggage handling system interchange. A station and depot will also be constructed to support the trains travelling between Terminal 2 and Terminal 5.
Changi Airport Group had earlier announced a separate people mover service between the two terminals, linked by a 2.5km underground route that began construction in 2024. When operational, five trains will serve this route, with two running at any one time. Each train can carry up to 96 passengers along with their baggage, and the journey will take about four minutes one way.
The baggage handling tunnel will be able to process up to 3,000 bags per hour. For now, a conveyor belt system has been installed inside the tunnel to transport excavated soil from Terminal 2 to Terminal 5. Dr Wen said this method avoids the need for trucks, which “could lead to congestion at the airport,” adding that the conveyor belt has eliminated this issue.
Terminal 5 Updates
Terminal 5, which broke ground in May, is scheduled for completion in the mid-2030s. In its first phase, it will be able to handle about 50 million passengers annually, increasing Changi Airport’s total capacity. The terminal will also feature a ground transportation centre integrating train, bus and taxi services, as well as a new MRT interchange connecting the Thomson-East Coast Line and the Cross Island Line.
