Rails are pre-stressed to help them resist the effects of high
temperatures. In Britain,
our rails have a stress-free temperature of 27 degrees -
halfway between the coldest and hottest we expect our rails to
get in the UK.
We also tension our overhead line equipment to cope with
heat. When the air temperature reaches 30 degrees Celsius,
the temperature on the rail can be up to 20 degrees higher.
One of our hottest ever recorded rail temperatures was
62 degrees.
If we stressed our rails for exceptionally hot weather,
they wouldn't be safe for the winter and we'd have broken
rails because it's too cold.
That's why other countries choose different temperature
ranges depending on their climate.