Using solar reflective materials on trains to cool down carriages
Managing the temperatures of train interiors is an important issue, because UK temperature records are breaking records with increasing frequency. In July 2022, 40⁰C was topped for the first time.
Train interiors can become extremely hot, causing discomfort or serious health issues to those onboard—especially if the train is stranded and air conditioning systems are faulty.
There is an urgent need to increase climate change resilience on the railway, using existing technologies such as air conditioning. Unfortunately, full-sized air conditioning units are difficult to install on GB loading gauge. It is therefore worthwhile exploring alternative cooling solutions, such as solar reflective materials.
RSSB conducted a knowledge search on solar reflective materials to examine current options available and followed up with research project T1310 on their suitability for the GB railway.
Currently, solar reflective materials are infrequently used on the GB railway, so T1310 examined their suitability for use on GB rolling stock. It also explored whether trials and guidance on their use would be beneficial.
Informed by prior work carried out in the United States, RSSB considered a range of solar reflective materials and proposed moving to physical testing to determine the real-world implications.
The potential financial savings from installing solar reflective materials could be around £3k per carriage over 10 years, for electric multiple units and diesel multiple units (DMUs).
This is because, on vehicles without operational air conditioning units, solar reflective materials have the potential to reduce carriage temperatures by 7–10°C.
If all 589 DMU carriages from southern England train operating companies use solar reflective materials, an achievable estimated benefit value is £1,415,000.
This research also shows that further research about the use of solar reflective materials in rail would be useful. Other operational areas where solar reflective materials could be used include stations and maintenance sheds.