Balfour Beatty, Alun Griffiths and Siemens Mobility have secured the first projects, including control systems, track work, stations and the new fleet maintenance depot in Taff’s Well.

Giffiths’ package is for stations and civils works as well as site preparation for a £50m tram-train depot and integrated control centre in Taff’s Well, north of Cardiff.

Balfour Beatty’s ECI packages cover permanent way and traction power. Most of the Core Valley Lines will receive 25kV overhead electrification equipment.

Siemens Mobility will deliver signalling works.

The firms will now work with TfW on final designs and establish supply chains with local Welsh businesses.

Transport for Wales is transforming the transport sector across the Wales and Borders network with a £5bn investment programme.

James Price, chief executive of TfW, said: “We will work closely with Balfour Beatty, Alun Griffiths and Siemens as they help us develop our vision of a high quality, safe, integrated, affordable and accessible transport network of which the people of South Wales are proud.”

Mick Rayner, managing director of Balfour Beatty Rail, said: “This marks a significant milestone in the delivery of Transport for Wales’ investment programme and the South Wales Metro project, which on completion will significantly improve transport links in South Wales.

Shaun Thompson, rail director at Griffiths, said: “As a Welsh company that self delivers, it enables us to recruit and train new local employees, enhancing the economy in Wales. Being involved right from the start on these ECI contracts, allows our people to add value by innovating, promoting health and safety and reducing risk.”