Transport for Wales and Network Rail have urged passengers to only travel if absolutely necessary as a red extreme heat warning comes into force across parts of South Wales.
The Met Office has issued the warning from 9am on Wednesday 24 June until 9pm on Thursday 25 June, with temperatures forecast to reach as high as 38°C.
In a joint statement, Transport for Wales and Network Rail warned that the extreme temperatures are likely to cause significant disruption to rail services, with delays and cancellations possible across the network.
Passengers travelling into, through or out of the red warning area are being advised to reconsider their journeys, while those travelling elsewhere are urged to check before setting off.
Extreme heat can affect railway infrastructure, including tracks, overhead power lines and trains. As a result, speed restrictions may need to be introduced, meaning some services could take longer than usual.
Transport for Wales said passengers should check their journey using its app, website or live travel map before travelling and allow extra time for their journeys.
Travellers are also being advised to carry plenty of water and stay hydrated. Anyone feeling unwell during their journey should seek assistance from station or onboard staff.
The warning comes as South Wales is expected to see increased demand from people travelling to coastal destinations during the hot weather.
Additional pressure is also expected on the rail network in Cardiff, where thousands of music fans are set to attend The Cure’s sold out concert at Blackweir Fields on Wednesday evening. Queue management systems will be in place at key stations to help manage passenger numbers.
To provide greater flexibility, Transport for Wales has confirmed that tickets dated Wednesday 24 June and Thursday 25 June can be used on Friday 26 June if passengers decide not to travel on their original date.
Customers who no longer wish to travel can also apply for a full refund from their point of purchase, provided the claim is made before 11.59pm on the day before the ticket’s date.
Passengers may also travel earlier than their scheduled departure time on both days.
Transport for Wales and Network Rail are continuing to monitor conditions and are urging customers to keep up to date with the latest travel information before making their journeys.
