A number of new electric trains are moving into service in south Wales.
The trains will begin on the valley lines before being moved across to the Vale of Glamorgan and Rhymney lines in late 2025.
These electric 'tri-mode' trains, the first of their kind in the UK, can use diesel or battery on sections of track without overhead wires.
They entered passenger service on November 18 on the Merthyr and Aberdare lines, followed by the Treherbert line.
This marks a significant step in the South Wales Metro project.
14 trains are expected to be in service by spring 2025.
Ken Skates, cabinet secretary for transport and north Wales, said: "This is great news and a truly historic moment as we see the introduction of the first brand new electric trains on the South Wales Metro.
"These state-of-the-art electric trains with greater capacity will make passengers' journeys more comfortable and with the addition of the latest technology allowing for Wi-Fi and up-to-the-minute travel information screens, are sure to encourage more people to use the train for their travel needs."
Built by manufacturer Stadler, the new Class 756 Fast Light Intercity and Regional Trains (FLIRTs) will be powered by newly installed overhead electrified wires.
James Price, Transport for Wales CEO, said: "This is a huge moment for TfW and Wales, as we’re the first in the UK to be introducing this modern ‘tri-mode’ train into passenger service.
"We’ve been modernising and electrifying the railway line and we are now extremely proud to be able to introduce the first of our brand-new trains that will be powered by electricity."
Over the last two years, Transport for Wales has introduced 65 brand-new trains and seven premier class MK4 trains to the Wales and Borders network as part of an £800 million investment.
By late 2025, the trains will move to the Rhymney and Vale of Glamorgan lines as the new tram-trains enter passenger service.
They will then travel from Coryton and Caerphilly to Penarth, and from Rhymney to Barry Island and Bridgend.
The electrification of the Merthyr, Aberdare, and Treherbert lines has been crucial for the trains' introduction.
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