There'll be no trains on the Cardiff Bay line for the next two weeks due to major engineering works.
Transport for Wales (TFW) is redeveloping the Cardiff Bay station and creating a new two-platform station in the north of Butetown.
The line will eventually be electrified in order to introduce brand new trains as part of the South Wales Metro.
The closure, which runs until Sunday 25th May, means there'll be no services between Cardiff Queen Street and Cardiff Bay. The half-hourly services to and from Pontypridd are also affected.
Passengers are being urged to check before they travel.
TFW chief infrastructure officer Dan Tipper 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."
The engineering works will see track being installed on the line running into the new platform 2 at Cardiff Bay, temporarily replacing the existing platform 1 that is currently used for services to and from Queen Street.
Sheet piling work is also being carried out at the new Butetown station, while new wires will be installed for the overhead lines to run the new electric tram-trains which will run on the line.
During the line closure, passengers can use their ticket on Cardiff Bus services at no extra charge. Some replacement buses between Queen Street and the Bay will run during the early morning and late night, along with buses between Radyr and Cardiff Bay on Saturday 18th May.
When the line reopens on 26th May, passengers will only be able to access Cardiff Bay station onto platform 2 from Lloyd George Avenue, instead of platform 1 from Bute Street.
TFW is also urging the public to obey trespassing rules and stay clear of any electrical lines while electrification work takes place in the coming months. Anyone caught trespassing could face a £1,000 fine.

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