Repair works are taking place on the Severn Tunnel, a key route between Wales and England.
Essential works are underway on Severn Tunnel, with engineers expected to be remaining on site throughout Sunday, August 25.
A limited replacement bus service is running in place, with passengers encouraged to travel by train via Gloucester.
Network Rail bosses have asked passengers to “check their journeys before they travel”.
The repairs are essential maintenance to the overhead conductor rail that powers the electric trains.
There are limited buses between Bristol Parkway and the Severn Tunnel junction today, and a full replacement bus service will be put on between Bristol Parkway and Newport on Sunday.
This is not the first time this summer that the route has been closed, as track repairs were carried out on the side in South Wales between July 3 and 18.
Teams will be compacting the ballast – or stones – on the track inside the tunnel using a special tamping machine.
This is as well as the essential maintenance to the overhead conductor rail that powers electric trains.
This work will help keep trains running safely and smoothly.
The project is follow-up work to a much larger track upgrade inside the tunnel in July.
It’s the final step that will keep the new ballast supporting the track for years to come.
Network Rail Wales has thanked passengers for their patience during this period of closure.
Network Rail Wales and Borders route director Nick Millington said: “I would like to pay tribute to the dedication and skill of the Network Rail teams and our contractors, who worked 24/7 in challenging conditions to safely deliver the largest track replacement in the tunnel for many years.
“We are committed to providing lower-carbon and reliable rail transport between South Wales and England – and this major track renewal on such a busy route is a significant part of that.”
Train services along the route are due to resume on Monday.
