National Rail advises passengers to “only travel if absolutely necessary” on selected rail journeys in London during the current heatwave, according to reporting that lists affected services. The guidance is issued for travel on Wednesday or Thursday, reflecting concerns about how extreme temperatures could affect train performance and safety. The Evening Standard publishes a full list of the train services covered by the warnings, and other outlets repeat the same framing while directing readers to that list. The advice applies to passengers considering travel on the specified days and is intended to reduce demand and mitigate disruption risk in high-heat conditions. In practical terms, the public messaging emphasises avoiding non-essential trips and checking updates before travelling. While the reports focus on the “do not travel” warnings and the scope of affected services, they do not provide broader operational details beyond the overall National Rail instruction for the heatwave period.