The 130-year-old Severn Tunnel, which links Gloucestershire and Monmouthshire, has closed for work on the electrification of the Great Western Railway line.

The work will prepare the railway for a fleet of brand new electric trains, which will result in more seats and faster, “more reliable” train journeys.

During the six-week closure Network Rail will install over eight miles of electrical equipment which will power a new fleet of electric trains.

Andy Thomas, route managing director for Network Rail Wales, said: “Wales is open to passengers and freight traffic during this essential upgrade, but we are urging people to plan their journey ahead.

“This iconic project marks a major milestone in the delivery of electric trains to Cardiff by 2019.

There are significant long-term benefits including faster, ‘greener’, more frequent trains, as well as a boost to the economic growth in South Wales thanks to better connectivity to and from London — a critical factor for attracting inward investment.”