Too hot for train travel? Heatwaves and the UK rail network
5th August 2019
Adverse weather plays havoc with the UK rail network. Flooding and high winds have proven major issues over the past few years, and in 2018, the ‘Beast From the East’ caused havoc across all transport systems, especially rail. But it’s by no means only winter weather that causes such disruption, as the recent heatwave has proven. It wasn’t just any heatwave either – Thursday 25th July went down as as the hottest day on record in the UK, with a temperature of 38.7C. And it brought problems across the rail network with it. Baking temperatures, delays, cancellations and even evacuations caused huge issues.
In 2015, National Rail produced Network Rail’s Second Climate Change Adaptation Report, which considers the impacts of higher temperatures, and other adverse conditions caused by climate change – as well as actions to combat them. The Department for Transport’s High Level Output Specification for 2019 to 2024 also contains the requirement to “manage the resilience of the network to severe weather, taking account of the impacts of climate change”.
There are a multitude of problems that extreme heat causes to rail travellers; here are 3 of the biggest.
Unbearable on-board temperatures
This July, passengers were faced with temperatures as high as 40C in carriages, coupled with delays, making conditions incredibly uncomfortable. In some cases, faulty air-conditioning systems led to train staff distributing water to passengers and even evacuating.
Old stock is one of the main issues; on average, UK carriages are over 20 years old – consequently, their air conditioning units often aren’t fit for purpose. Newer carriages have far better-performing heat-management systems; some even harness energy from braking to run them. For the first time, the Department for Transport has stated that the rail industry must bring in requirements on the fitting and maintenance of heating, ventilation and air-conditioning systems.
Sagging of overhead lines
High temperatures often cause overhead powerlines to expand and sag. Trains must then travel more slowly to avoid damaging the cables, and damaged cables often cause delays.
Modern overhead lines are far less affected, due to their auto-tension systems, which adjust to suit different temperatures. But much of the UK network is serviced by older lines, which are fixed-tension and more susceptible to sagging.
Buckling of tracks
A big issue in warm weather is the ‘buckling’ of railtracks. Tracks can reach 20°C hotter than the air, and the heat causes the steel to expand and curve. Once air temperature is over 30C, the risk of buckling increases dramatically.
There are ways to reduce the chance of buckling – sections of rail that are painted white are up to 10C cooler and tracks laid on reinforced concrete slabs are also less susceptible. Remote monitoring systems can give warning of track temperatures, allowing buckling to be avoided in many cases.
There’s no doubt that the performance of our network in hot conditions must be improved, particularly as temperatures are on the up. Due to climate change, periods of such high temperatures will become more commonplace, and maximum temperatures are predicted to increase. It’s more vital than ever that our railways can function in hot weather.
Our network needs to be modernised – as does our approach. We are already making great progress, so we simply need to build upon it. As warmer weather becomes more frequent, the performance and comfort of trains under such conditions becomes more important, especially when it comes to retaining current customers and attracting new ones. In order to mitigate the effects of global warming and climate change, we need to encourage more people to make the switch to rail, given that trains are a relatively low-carbon mode of transport. When it comes to climate change, trains that perform well in heat are both a necessity and part of the solution.