Travellers on the railways have been warned to only make essential journeys amid heatwave disruption in mid Wales. 

Transport for Wales warned of possible travel disruption over the coming days due to the forecast high temperatures, and has recommended checking on changes to service in case of heat-related issues that could slow the rail system.

And the rail operator has warned it will cancel some services heading beyond Shrewsbury into Birmingham on Monday and Tuesday - a route covered by the Met Office's red "danger to life" warning.

But it also said it was seeking to provide additional capacity on the Heart of Wales line in advance of the Royal Welsh Show, which begins on Monday.

Temporary speed restrictions look set to be in place across the rail network to “reduce the risk posed by overheating rails leading to longer journey times”. This could lead to short-notice changes to services.

Transport for Wales is also warning that “extreme temperatures could also lead to other infrastructure and fleet challenges such as track faults and overheating engines” which could lead to delays or cancellations

Customers are also being encouraged to stay hydrated by taking a bottle of water and free water refill points are being made available at Llandudno, Machynlleth and Cardiff Central stations.

These warnings come after the Met office issued a rare amber warning for heat, with temperatures in Wales set to reach into the mid-30s.

Colin Lea, Transport for Wales’ Planning and Performance Director, said: “We continue to see very high demand for our rail services, particularly during periods of good weather. All available carriages are in service and where possible, we’re providing supplementary road transport.

“It’s now more important than ever to plan ahead using information our new website, our recently updated app or our social media channels. Passengers should consider whether they want to travel on trains that are likely to be full and standing, and use our Capacity Checker – an online tool that allows customers to see which trains are likely to have the most space available.”

Dan Booth, seasons delivery manager, at Network Rail Wales and Borders, added: “We do everything we can to limit disruption for passengers during hot weather, but safety is our number one priority.

“Speed restrictions are likely to be in place across many parts of Wales and Borders, as slower trains reduce the risk of damage to the tracks when they expand during extreme temperatures.

“We advise passengers to carry a bottle of water and please check journeys before travelling for any delays or disruption.”