Network Rail will invest more than £25m in the North Wales Coast railway during a major programme of work scheduled for January 2027.
The four-week closure will run from Saturday 9 January to Saturday 6 February, allowing engineers to renew infrastructure between Chester and Holyhead. The work is intended to improve reliability, capacity and safety on a route where some assets are more than 50 years old.
Planned closures and upgrades
For the first three weeks, the railway will be closed between Chester and Holyhead, including the Conwy Valley line and the route between Llandudno Junction and Llandudno. During the fourth week, the closure will be limited to the section between Llandudno Junction and Holyhead.
Network Rail said it had reduced the closure between Chester and Llandudno Junction from four weeks to three. Rail replacement services will operate, with detailed arrangements expected to be published in autumn 2026.
The programme includes track renewal through the Grade I-listed Conwy Tubular Railway Bridge, where the track dates from 1978, as well as track and drainage improvements in Bodorgan Tunnel. The tunnel infrastructure dates from 1972 and the work is intended to reduce flood risk.
Further track and ground improvements are planned at Penmaenbach, where sections were last renewed in 1986. Work will also take place on track and points at Holyhead and Llandudno, platforms at Llandudno Junction, and four level crossings east of Bangor.
Network Rail will carry out around £1.4m of vegetation management at nine locations. Two new fully accessible footbridges at Prestatyn and Abergele will support the closure of four high-risk level crossings.
Work to support higher service levels
The work will be delivered using 22 engineering trains and on-track machines. Network Rail expects to install more than 3,000 concrete sleepers and 9,000 tonnes of ballast, while approximately 9,800 tonnes of spoil will be removed for recycling and reuse on future railway projects.
The investment follows the introduction of a new North Wales timetable in May 2026, which increased Transport for Wales services by 50%—the largest timetable improvement in North Wales for a generation, according to Network Rail.
Network Rail said the closure would also allow additional maintenance to be completed alongside the main renewals, reflecting the increased number of trains now using the route.
Emma Osborn, passenger strategy director for Network Rail’s Wales and Borders route, said the programme would bring together years of complex work in one intensive intervention rather than requiring a prolonged series of weekend closures.
“The long-term benefits for passengers and freight customers will far outweigh this temporary disruption, with a safer, more reliable railway that is better equipped to support the increased number of services now running across North Wales,” she said.
Colin Lea, planning and performance director at Transport for Wales, said the track maintenance, tunnel drainage and accessible footbridges would help provide a more reliable service and improved stations.
Avanti West Coast operations director Chris Liptrot said services on the operator’s North Wales route would change during the works. He advised passengers to check the Avanti West Coast and National Rail Enquiries websites once the timetable had been confirmed.