With the Railway Order granted and tendering under way for €7.9bn of MetroLink contracts, the next decade of Dublin tunnelling will depend on continuous, high-precision monitoring of the ground above the bore.
MetroLink represents the most ambitious urban tunnelling programme in Irish history. Following the Railway Order granted by An Coimisiún Pleanála in October 2025, Transport Infrastructure Ireland opened bidding in February 2026 for civil works packages worth €7.9bn.
The southern section alone, from Charlemont to Northwood, comprises €4.56bn of bored railway tunnels, tunnel portals, evacuation shafts and station boxes excavated up to 35 metres below street level.
Twin tunnel boring machines launched from Northwood will advance through glacial tills and underlying alluvial soils beneath Dublin's densest urban fabric, passing under the Liffey, Trinity College, and decades of heritage building stock.
For the project engineers, the success metric is not only on time delivery. It is also the elimination of unacceptable surface settlement and structural damage to thousands of properties along a corridor where every millimetre matters.
Where RTK GNSS fits in the monitoring stack
Tunnel settlement monitoring is a multi-instrument discipline. Automated total stations, precise levelling, MEMS tilt sensors, and InSAR satellite interferometry each cover different aspects of the volume loss problem.
Real Time Kinematic GNSS complements these methods by providing absolute three dimensional co-ordinates across wide monitoring networks, particularly for surface points outside the immediate building damage assessment zone where total station line of sight becomes impractical.
Typical RTK applications on a tunnel project of this scale include pre construction baseline surveys of monitoring monuments along the full alignment, periodic check measurements on the wider control network that anchors automated instruments, settlement monitoring of approach embankments and cut and cover station boxes, and as built verification of surface infrastructure once each TBM drive is complete.
Open NTRIP for multi-contractor environments
MetroLink will be delivered by international consortia, with the September 2025 memorandum of understanding between Alstom, FCC, John Laing, Meridiam and RATP Dev signalling the scale of the supply chain. On a project with multiple specialist surveying contractors, each running different receiver hardware, the open NTRIP standard becomes essential.
RTKdata.com delivers corrections from a network of more than 20,000 reference stations across 140 countries via the standard NTRIP protocol, compatible with receivers from Trimble, Leica, Topcon, Septentrio, Emlid and any other manufacturer on site.
This open approach matters when monitoring data feeds into a shared common data environment under the Irish BIM mandate. Coordinates captured by one contractor must be directly comparable with those captured by another, in the same reference frame, without proprietary conversion losses.
Subscription access for project teams
RTKdata operates on a subscription model starting at $40 per month, with volume licensing for monitoring teams running multiple rovers across an active corridor. A 30 day free trial allows engineering practices to evaluate network performance on representative sites before tendering: rtkdata.com/try-rtk-corrections-free-for-30-days.
As the MetroLink TBMs begin their advance later this decade, the engineering profession in Ireland will be tested on its ability to detect, quantify, and respond to ground movement in real time. Accessible, accurate, open standard positioning is part of how that gets done.