Iarnród Éireann has commenced the FourNorth programme, a transformative upgrade to the existing two-track railway between Dublin Connolly and Malahide.
The line is the busiest rail corridor in the country, with northside DART, Northern Commuter, Belfast Enterprise and rail freight services all sharing the existing two tracks. FourNorth will allow more capacity, more services and more reliability by proposing the provision of additional tracks alongside the existing two-track railway between Dublin Connolly and Malahide stations.
Today, this constrained layout limits capacity, particularly during peak periods, with even small disruptions rippling across the network.
FourNorth aims to address these challenges by removing critical bottlenecks and unlocking additional capacity for rail movements. This will allow trains to flow more smoothly through the corridor, improving timetable performance and making better use of the existing network, and making space for the future: increasing capacity, improving frequency and enhancing reliability to create a more resilient rail corridor that supports local, regional and national travel for decades to come.
Funded by the Department of Transport and the Connecting Europe Facility Transport programme, Iarnród Éireann will today publish initial details of the project aims and priorities, as the programme progresses through early option development.
Why FourNorth matters
The Connolly to Malahide section of railway is the main gateway for North Dublin commuters travelling into the city centre and a key link between the island of Ireland’s two largest cities.
FourNorth will seek to address the challenge of a critical bottleneck on this section by delivering three core improvements:
- Capacity – Increased capacity, creating space for more trains and more passengers.
- Frequency – Faster, more predictable journeys including at peak hours.
- Reliability – Fewer delays, wait times and disruptions including less maintenance closures through greater operational flexibility.
Together, these upgrades will enable more frequent train services, better connections and a stronger, more dependable rail network.
Key benefits for passengers and the network
FourNorth will deliver wide-ranging benefits, including:
- More train services and increased capacity to accommodate higher passenger volumes.
- More frequent operations through reducing conflicts between different services on the existing twin-track railway, and smoother service flows.
- Enhanced reliability, with fewer delays and more consistent performance.
- Stronger connections, supporting faster journeys between North Dublin, Meath, Louth and Belfast.
- A better day-to-day journey experience, with improved comfort and more punctual, frequent and dependable services for all passengers.
Beyond these immediate gains, FourNorth will play a strategic role in Ireland’s transport future. The project supports sustainable travel by encouraging a shift from car to rail, strengthens integration with other major public transport investments, and enables transport-oriented development by improving access to jobs and education.
Strategic alignment
FourNorth aligns with Ireland’s climate, connectivity and sustainable growth objectives, as well as European transport priorities. By tackling a major capacity constraint on the Dublin-Belfast corridor, the project supports faster, more reliable cross-border travel, strengthens the Greater Dublin Area public transport network, and contributes to national decarbonisation targets.
It also creates the conditions for future expansion with alignment to the All-Island Strategic Rail Review (AISRR) – including potential heavy-rail connectivity to Dublin Airport and, over the longer term, the proposed cross-Dublin tunnel connecting the Northern Line with Heuston Station as well as a future railway broadly aligned with the M1 corridor, as identified in the All-Island Strategic Rail Review.
At a European level, FourNorth also improves performance on a core TEN-T corridor, helping deliver the high-capacity, resilient rail infrastructure required for a modern, interconnected transport system.
Together, these policy drivers support a higher-quality rail network with the capacity and reliability commuters need for the future.
Funding and engagement
FourNorth is jointly funded by the Department of Transport and the Connecting Europe Facility Transport programme. The project is currently in early option development, and future specific funding streams will be confirmed through the Preliminary Business Case, with information shared publicly as this work progresses.
Iarnród Éireann plans to begin public engagement in late 2026, giving communities, passengers, businesses and local authorities the opportunity to help shape the emerging design.
Consultation will take place at key stages and will include online resources, mailed information, public events and hosted sessions – designed to provide clear project updates and meaningful opportunities for feedback for all stakeholders.
Where the project is now – and what happens next
FourNorth is currently in the early design and option development stage. Multiple options have been assessed to identify an Emerging Preferred Option that best balances engineering, operational, environmental and community considerations. The Emerging Preferred Option will be presented via consultation later in the year.
Iarnród Éireann Chief Executive Mary Considine said “FourNorth is about more than new tracks. It is about building a resilient, high-capacity rail corridor that supports everyday journeys, strengthens regional connections and helps deliver a sustainable transport future for Ireland – making space today for the needs of tomorrow. We look forward to developing and confirming the preferred option throughout the remainder of this year, and to the input of our customers, the communities we serve and all stakeholders.”
Minister for Transport Darragh O’Brien said:
I welcome the progress being made on design on the FourNorth project. This Government is already making investments in the Northern Line to help ease rail congestion. Passing loops and turnback facilities are to be delivered at Mosney, Skerries, Malahide and Clongriffin in the next few years, supported by funding from the EU and the Shared Island Fund. These investments will improve journey times and reliability for Enterprise and DART passengers, including those who will benefit from the new battery-electric DART+ fleet operating as far north as Drogheda from the middle of next year under DART+ Coastal North.
The rail line between Dublin Connolly and Malahide is one of the busiest on the island, and track capacity is a major constraint on frequency and capacity upgrades. The Four North project will not only unlock future growth and support additional DART, Commuter and Enterprise services, but will also enhance reliability and enable speed improvements for the services already operating today.
Minister of State with responsibility for International and Road Transport, Logistics, Rail and Ports, Seán Canney said:
FourNorth represents a long-term and transformative investment in rail capacity, in line with our 2050 vision set out in the All-Island Strategic Rail Review. Improvement of public transport services, and especially rail infrastructure, is key in improving people’s lives and unlocking economic growth, which is why I am very glad to see this critical project advancing through the design stages. I encourage the public and interested stakeholders to engage with the consultation process, as their feedback will be an important part of the design process.