Passengers on the Brighton Main Line may face cancellations and delays today and tomorrow, because of the high temperatures.
The maximum in Croydon is forecast to be 31C today and slightly hotter tomorrow, and inland towns in West Sussex are likely to be almost as warm.
Network Rail has imposed speed restrictions because the internal temperature of the rails could be 20C hotter than the air.
Rails in Britain are pre-stressed to a rail temperature of 27C, which usually works well in our climate, but the force of trains weighing several hundred tonnes is made more extreme when temperatures are very high. One way of reducing that force is to run at lower speeds.
Network Rail said: ‘With temperatures set to soar as forecast by the Met Office, speed restrictions have to be imposed across large parts of the network to ensure everyone’s safety.
‘We’re sorry but this means we won’t be able to run as many trains as normal and journeys will take longer. Trains that are running will also be much busier. If you are able to work from home then that may be your best option.’
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