MetroLink Dublin is a proposed metro line that will run from north county Dublin through the Airport to south of the City Centre. It will be 19.5 km long, mostly underground with 16 stations. Estimated cost is €9.5 Billion. Construction could commence in late 2025 and be operational in 2033. Planning submission will be lodged this September. Single tunnels 9.6 metre diameters between stations will be bored using a Tunnel Boring Machine (TBM). The tunnel will be lined with precast concrete segments, have two tracks laid side by side for trains travelling in opposite directions. The tunnels will be deep underground in rock to minimise settlement. Full height platform screen doors to prevent passengers falling onto tracks. 3D Cutaway of underground station & tunnel to show construction methods and design. The station box will be 125 metres long by 25 metres wide and 24 metres deep.
The trains will not have drivers and will be fully automated. The journey time from the airport to the city centre will be 20 minutes.

MetroLink will have the capacity to carry up to 20,000 passengers per hour in each direction with trains every 90 seconds.

The Station box is constructed using secant pile walls down to bed rock level that generally varies between 5 and 15 metres below ground level. The overlying deposits are generally boulder clay with thin layers of sand and gravel. The rock is limestone and mudstone. The tunnels will be in rock to avoid ground loss and settlement. After the walls are constructed the earth inside and rock below will be excavated and carted off site by trucks.

One of the first jobs is to demolish houses and divert underground services, paths and roads at the location of Stations.

Shown is a timeline with main stages for the design and construction.

Tunnelling will start south of the Airport and head north under the Airport. The Tunnel Boring Machine will be relaunched at Northwood and tunnel to Charlemont.
The tunnel boring machine also known as a TBM is used to excavate and place the concrete precast curved tunnel wall segments that form the tunnel wall. The tunnel boring machine pushes itself forward by jacking off the placed wall segments as the head rotates and digs the tunnel.
The tunnel precast concrete segments are delivered by road and lifted into the underground station and carted through the tunnel under construction to the back of the tunnel boring machine. The rock excavated and by the TBM is transported out of the tunnels on conveyor belts.


Footage showing the Copenhagen Metro from the Airport to the city centre.