Core Valley Lines Transformation, Wales

A major scheme to improve and renew existing assets across South Wales to improve connectivity and make sustainable travel easier for 1.5 million people.

Working alongside Transport for Wales, Siemens, Alun Griffiths and Amey Infrastructure Wales, Balfour Beatty is part of the Craidd Alliance responsible for delivering the £378 million Core Valley Lines (CVL) Transformation programme.

Scope of works

Our team is responsible for improving, renewing and electrifying the existing rail assets across the South Wales. Through a multi-disciplinary approach, our scope of works includes:

  • Track – 26 major enhancements including re-doubling, line speed improvements, track lowers and the remodel of Queens Street Station
  • Electrification – powering the 25kVA overhead line to 172km of track
  • Construction – improvements to 52 stations within CVL
  • Signalling - including cable diversions, cable monitoring, relocation of signalling cases, reinstating and testing of signalling equipment
  • Civil engineering – hundreds of line side civil interventions including trough installation, under track crossings, retaining walls, drainage and culverts

volunteering hours


STEM ambassadors

World-first collaboration accreditation

The Craidd Alliance were the first rail Alliance to secure an international accreditation for collaboration in the world.

The IS044001 accreditation is the international standard for collaborative business relationship management systems and recognises the Alliance’s approach to sharing its resources, experience and skills to benefit its suppliers, customers and partners.

Balfour Beatty and its partners were also commended at the 2021 Institute for Collaborative Working Awards, winning the prestigious Industry Award for Collaboration.

Leaving a positive legacy

The CVL project team has worked on over 80 community projects across Wales, delivering 700 hours of volunteering. Other social value initiatives include providing 127 weeks of work experience to people in the local area.

11 members of the team joined as part of a rehabilitating offender’s programme, an example of how the project is embracing new initiatives to improve lives and drive employment opportunities in the local community. ​​​​​​

The project team boasts 18 Science, Technology, Engineering and Maths (STEM) ambassadors and has visited over 20 schools to deliver in person and online activities, resulting in over 1,500+ children and young people connecting with the project.