Wednesday 18 Mar 2026
Major rail upgrade plans submitted to help unlock new railway stations
Region & Route: Wales & Western: Wales & Borders
SWML at Bishton
Passengers are closer to benefitting from improved rail services, better connectivity and new stations as Network Rail submits a full business case for major railway upgrades between Cardiff Central and Severn Tunnel Junction.
This March, Network Rail Wales and Borders formally submitted the full business case for the South Wales Relief Line Upgrade (SWRLU) - a key infrastructure project designed to increase the speed and performance of relief lines and unlock the capacity needed for future passenger services.
The upgrades will play a vital role in supporting plans for new stations across the region, improving performance and unlocking better rail access for communities along the South Wales Main Line.
The proposals, submitted to the UK Government Department for Transport, include infrastructure improvements across 27 miles of track, with refurbishment and renewal works, as well as increasing speeds on the Up and Down relief lines from 40mph to up to 100mph, where feasible.
Subject to full business case approval, this work will allow for future increased line speeds on the relief lines that run alongside the main lines between Cardiff Central and Severn Tunnel Junction.
While these lines are currently used primarily by freight services, the improvements would enable them to accommodate passenger services, without adding time to journeys, creating additional capacity and improved reliability and performance across this vital section of railway.
The work will also allow freight trains to run faster, improving overall network efficiency.
This infrastructure work is a critical step in enabling the proposed development of up to six new stations in South East Wales - including Cardiff East, Newport West, Somerton, Llanwern, Magor & Undy, as well as Cardiff Parkway - which aim to improve local connectivity and make it easier for communities to access rail travel.