Warning to rail passengers as the UK braces itself for fifth heatwave with temperatures of 35C expected

Britain is bracing for yet another scorching spell, with temperatures forecast to rocket to 36c this Thursday.

As the heatwave returns, Doncaster rail passengers should expect slower trains and disruption across the network.

David Martin, Managing Director at rail precision tooling and maintenance equipment supplier Heamar, says Britain's rail network comes under significant strain during prolonged hot weather.

He reveals the six main reasons why trains are slowed down during a heatwave, and why those delays are often keeping passengers far safer than they realise.

1. Train tracks can literally buckle in extreme heat

"Most people don't realise that railway tracks can become far hotter than the air temperature. On a warm summer's day, the steel rails themselves can easily exceed 50°C.

"Like any metal, steel expands as it heats up. If that expansion becomes too great, the rails can begin to move sideways and buckle. Even a slight distortion in the track can create a serious safety risk for trains travelling at speed.

"That's why operators introduce temporary speed restrictions during periods of extreme heat. Slower trains place less force on the rails, reducing the likelihood of a buckle developing while allowing services to continue operating safely."

2. Overhead power lines begin to sag

"For electric trains, it's not just the rails that are affected. The overhead wires that supply electricity also expand as temperatures rise. As they stretch, they naturally begin to sag lower than normal.

"If trains continued travelling at full speed, the pantograph on the roof, which collects power from the overhead line, could place greater strain on the wires, increasing the risk of damage or even bringing the line down altogether. Reducing train speeds helps maintain smoother contact and lowers the risk of widespread disruption."

3. Critical signalling equipment can overheat

"The railway depends on thousands of pieces of electronic equipment to keep trains moving safely, including signals, sensors, and trackside control systems.

"During a heatwave, the cabinets housing this equipment can become extremely hot, placing additional stress on sensitive electronics. If a signalling system overheats or develops a fault, trains may need to slow down or stop completely until engineers can confirm it's safe.

"Passengers might only notice another delay, but these systems are designed to prioritise safety above everything else."

4. The ground beneath the tracks can shift

"It's easy to focus on the rails themselves, but the ground underneath them also changes during prolonged periods of hot, dry weather.

"Certain types of soil, particularly clay, shrink as moisture evaporates. That movement can affect the stability and alignment of the track above.

"Even very small shifts have to be inspected carefully, which is why trains may be slowed while engineers assess the infrastructure and ensure everything remains safe."

5. Many speed restrictions are introduced before anything goes wrong

"One of the biggest misconceptions is that delays only happen after something has failed. In reality, many heat-related speed restrictions are entirely preventative.

“Engineers constantly monitor rail temperatures and weather conditions, and if the risk of track movement becomes too high, trains are slowed before damage has the chance to occur.

"Although that can be frustrating for passengers, these precautionary measures often prevent a short delay from turning into hours of disruption."

6. Engineers carry out far more inspections during a heatwave

"Extreme weather means railway engineers are carrying out many more inspections than usual.

"If monitoring equipment detects unusually high temperatures or signs that infrastructure is under additional stress, teams may need access to inspect rails, overhead lines or signalling equipment before trains can continue at normal speeds.

"Those checks can sometimes add a few minutes to a journey, but they're a crucial part of preventing larger failures and keeping the railway running safely throughout periods of extreme heat."

For more visit: https://www.heamar.co.uk/torque-tools/torque-wrenches.html