Mark Langman, Network Rail’s route managing director for Wales, said: “We are extremely pleased and excited by the UK Government’s announcement to electrify not only the route from Cardiff to Swansea but also the Valleys lines network.

“Wales relies on rail and this electrification announcement will be a real boost to the economy of South Wales. New and longer trains will deliver more seats and quicker journeys to London, improving the passenger experience and also driving economic growth. Whilst electrification of the Valley lines network will give the opportunity to explore further options to improve services and help unlock the economic potential of the region.

“This news is on top of the massive investment programme already underway in South Wales. The programme to date has delivered a modern signalling system between the Severn Tunnel and Newport as well as a new station building and platform at Newport. We will also soon be starting work on a major scheme in the Cardiff area to improve reliability and capacity.

“This is a strong vote of confidence in the railway, and in our ability to deliver sustainable economic growth through development of, and investment in, the network. It is also a vote of confidence in the success of rail over the last decade, with over one million more trains per year, half a billion more passengers, and record levels of safety, punctuality and satisfaction.

“This is an exciting time for the railway in South Wales and we are looking forward immensely to developing and delivering the electrification projects over the coming years.”