South Wales electrification

Work to electrify the South Wales Mainline – an important rail route linking major towns and cities – is well underway.

We are electrifying the line between London and Cardiff – a major part of our Railway Upgrade Plan. This will result in the introduction of bi-mode trains – trains that can run on electric and diesel – providing extra seats and faster services for thousands of passengers and a quieter and greener environment for lineside neighbours. The South Wales Mainline runs from the Severn Tunnel in Monmouthshire, through Newport, Cardiff, Bridgend, Port Talbot, Neath and Swansea.


Severn Tunnel upgrade

We’ve carried out significant work on the Severn Tunnel to prepare it for when the South Wales Mainline is electrified.

Image 1: Contractors working on the demolition of the western half of Splott Road bridge

Image 2: Crane in place ready for the demolition of Splott Road bridge

Image 3: Digger next to the railway track on the site of the demolished bridge

Newport station

To electrify the South Wales Mainline, we have been carrying out essential work on the platforms at Newport station since 2016, and this is expected to continue throughout 2018. Passengers are reminded that platforms will remain open during our work.

Ongoing station work includes:

  • preparing the platforms and canopies for posts and overhead electric wires (OLE)
  • removal of the redundant footbridge over the platforms
  • 75% of the canopy reductions and 90% of OLE foundations have been completed. The remaining canopy reductions and OLD foundations will be completed throughout 2018.


  • upcoming work to the Newport Tunnels, west of the station, in 2018
  • Tunnel Terrace footbridge reopened on 28 February 2018
  • Hawse Lane and Green Lane road bridges are due to reopen in early 2018
  • piling and post installation for OLE will continue through Newport and along the South Wales Mainline throughout 2018.


We have now completed our work to the bridges in Monmouthshire which required reconstruction. Our piling work and post installation work will continue through Monmouthshire in 2018.

The new Tunnel Terrace footbridge
Tunnel Terrace footbridge was reopened in February 2018