08 May 2025

Transport for Wales (TfW) is continuing to deliver the transformation of the Cardiff Bay line, with the development of a new two-platform station in northern Butetown and the redevelopment of Cardiff Bay station.

As part of the South Wales Metro, the Bay line will also be electrified to enable enhanced service frequency and to introduce brand-new electric trains.

The Cardiff Bay line will close from Saturday 10 May to Sunday 25 May so teams can carry out engineering work for the delivery of the transformation. During this time, no services will run between Cardiff Queen Street and Cardiff Bay. The half hourly service between Pontypridd and Cardiff Bay will also not run during this time.

Dan Tipper, Chief Infrastructure Officer at TfW, said: “The Bay Line transformation will see the biggest upgrade to public transport in the Butetown and Cardiff Bay area for a generation and is an important part of the South Wales Metro.

“This round of engineering works will be an important step in the project’s delivery, seeing us make headway on the development of a brand-new station in Butetown and the redevelopment of Cardiff Bay station.

“Teams will also be busy installing the new wires for the overhead line equipment during the line closure so that we can run the brand-new tram-trains.

“I’d like to thank our customers and neighbours living near the railway for their patience as we carry out these works. Please check before you travel during this time.”

While teams carry out the engineering work, new track will be installed on the Cardiff Bay line running into the new platform 2 at Cardiff Bay station. This will replace the existing platform 1 that is currently used for services travelling from Cardiff Queen Street to Cardiff Bay, until the Bay line transformation project is complete. Teams will also carry out sheet piling work at the new Butetown station during the line closure.

From 26 May onwards, customers will no longer be able to access Cardiff Bay station from Bute Street onto Cardiff Bay platform 1. Customers will be diverted onto the new platform 2 from the Lloyd George Avenue side of the station.

Teams will also be carrying out piling works and installing the new wires for the overhead line equipment to run the new electrically powered tram-trains which will be introduced on the line. With electrified lines being installed on the Core Valley Lines in South Wales, including on the Bay line later this year, TfW would like to highlight to the public the dangers of trespassing on the railway. Trespassing on the railway is reckless, illegal and dangerous, and those caught could face a £1,000 fine.

With electrification work ongoing over the coming months, TfW is urging the public to obey trespassing rules and to stay clear of any electrical lines.

During the line closure, customers can use their ticket on Cardiff Bus services at no extra cost. A few early morning and late night replacement buses will run between Cardiff Queen Street and Cardiff Bay. On Saturday 18 May, some replacement buses will run between Radyr and Cardiff Bay. TfW is advising all customers to check before they travel.

The Bay line transformation project, part of the wider Core Valley Lines transformation for the Metro, has been part-funded by the European Regional Development Fund through the Welsh Government.