Train services across Britain are facing disruption as soaring temperatures force Network Rail to impose speed restrictions across tracks for safety.South Western Railway (SWR) has issued a general alert to all passengers, warning that services across its entire network "may be revised" throughout Tuesday due to the hot weather. A number of afternoon and early evening services have already been cancelled.This is affecting key routes, including journeys between London Waterloo and Weymouth via Winchester, Southampton, and Bournemouth, as well as services connecting London Waterloo and Aldershot via Woking and Guildford.Furthermore, some services between Exeter St Davids, Salisbury, and London Waterloo are now terminating at Basingstoke.Compounding the travel chaos, services at London Waterloo are also being disrupted by a signalling failure. Earlier on Tuesday, a report of smoke between the station and Vauxhall also caused additional delays.National Rail Enquiries said Elizabeth line services between London Liverpool Street and Stratford are disrupted.LNER said two speed restrictions on its routes are causing delays.Temperatures across the UK continue to soar (Getty)Its services are limited to 20mph on what are usually 125mph lines at St Neots, Cambridgeshire, and Tollerton, North Yorkshire.The operator said there is also some alterations to services because it is running more Azuma rather than InterCity225 trains, as the former have better air conditioning.Great Northern said damage to overhead electric wires mean it cannot run services between Cambridge and Kings Lynn.Disruption was expected to continue until 4.30pm.Overhead electric lines can expand and sag in hot weather.This results in trains having to travel more slowly to avoid damaging the lines.Steel rails also expand as they get warmer, reaching as much as 20C hotter than the air temperature when in direct sunshine.Trains are forced to run slower to reduce the likelihood of buckled rails.Meanwhile, the East Anglian Daily Times reported that a section of the A143 road in Stanton, near Bury St Edmunds, has melted in the high temperatures.The highway authority is applying sand and granite dust to the site to prevent further damage.LNER said two speed restrictions on its routes are causing delays (Getty/iStock)The AA said the number of breakdowns it attended between Friday and Monday was up 15% on the same period last year, as “heatwave conditions put extra strain on vehicles”.The company received 34,124 callouts over the four days, compared with 29,602 during the same bank holiday period in 2025.Sunday and Monday had the biggest year-on-year increases with callouts up 21% on both days, while on Saturday and Friday there were rises of 17% and 5% respectively.Lee Morley, AA expert patrol, said: “Hot weather can be tough on vehicles, particularly if they are already carrying a fault, low on coolant or stuck in heavy traffic for long periods.“Overheating can escalate quickly, so drivers should not ignore warning lights, rising temperature gauges, steam, unusual smells or any change in how the vehicle feels.“If something does not seem right, it is better to stop somewhere safe and investigate rather than push on and risk causing more damage.”