Railway line transformed as Metro upgrade replaces Victorian-era signalling

Mark Mansfield

One of the last railway lines in Wales to rely on a Victorian signalling system has been transformed as part of the South Wales Metro project.

The Treherbert line in the Rhondda Fawr has undergone a major upgrade, replacing a traditional token exchange system dating back to the 19th century with modern digital signalling controlled from Transport for Wales’ operations centre at Taff’s Well.

Until 2023, train drivers were required to collect a physical token before entering single-track sections of the railway and hand it back at the other end.

The Treherbert line was closed for nine months while engineers carried out the work, which included installing overhead power lines, upgrading track, extending platforms and improving station accessibility.

The route is now served by new Class 756 trains, introduced in 2025. The trains can operate using overhead electric wires, battery power or diesel, depending on the section of railway.

Transport for Wales said the line’s transformation reflects the wider modernisation of the South Wales Metro network, which aims to provide more frequent services across the Valleys and Cardiff.

Other improvements include new passenger information screens and the introduction of contactless pay-as-you-go ticketing across much of the south-east Wales rail network.

More than 4.5 million journeys have been made using the contactless system since it was introduced, according to Transport for Wales.

Marie Daly, chief operating officer at Transport for Wales, said: “We’ve been on a journey of transformation with rail in Wales and have replaced some of the oldest railway infrastructure with some of the most modern in Europe.

“Through this investment, we’ve also been able to remove older trains from the network and introduce brand-new fleets, alongside electrification and upgraded infrastructure.”

The Treherbert upgrade comes as Transport for Wales prepares to introduce its first fully electric tram-trains between Pontypridd and Cardiff Bay later this summer.

The vehicles will form part of the next phase of the South Wales Metro, which is intended to provide more frequent services on key routes serving the Valleys and the capital.