About Four North
FourNorth Existing Corridor Study Area
The Northern Line between Dublin Connolly and Malahide forms the FourNorth study area. The assessment process to date has identified the section between Dublin Connolly and Clongriffin as the area where the proposed changes can deliver the greatest operational benefit.
Why FourNorth matters
The Northern Line between Dublin Connolly and Malahide is a critical link in Ireland's transport network and a key part of the Dublin-Belfast corridor. It serves as the main rail route for passengers and freight between the island's two largest cities and connects communities across North Dublin, Meath, Louth, Down and Antrim.
Today, DART, Commuter, Intercity and Freight services all share the same two-track railway. This creates a capacity bottleneck that can limit flexibility, particularly when managing different services and responding to disruptions at peak times. Without intervention, pressure on the line will continue to grow, affecting the reliability of rail services across the network.
FourNorth aims to address this capacity constraint by providing additional rail tracks on the most constrained section of the Northern Line. Increasing rail capacity will create space to separate faster and stopping services, improving how the railway operates. In doing so, FourNorth aims to:
- Unlock space for faster and more frequent train services
- Improve journey times and service reliability for passengers
- Provide greater flexibility to manage delays, conflicts and maintenance works while keeping trains running
- Support current rail project and future rail investment identified in the All-Island Strategic Rail Review
- Strengthen local, regional, national and cross-border connectivity now and into the future
- Enable modern, electrified, high-capacity rail on a more resilient rail network.
Assessment completed to date indicates the main interventions are required between Dublin Connolly and Clongriffin, where additional tracks can deliver the greatest operational benefits.
