National Rail issues heatwave disruption warning (Image: I-Wei Huang)Passengers are urged to check before they travel, allow extra time for journeys and carry water, with refill points available at Network Rail managed and some larger stations. Anyone feeling unwell is advised not to board a train and to seek assistance from station staff or use help points on platforms. READ MORE: Street party is why neighbourhood is 'such a special place'Customers delayed by the conditions may be entitled to compensation for disrupted journeys. Meanwhile, the UK Health Security Agency has issued an amber heat-health alert for the south east, which will remain in place between Tuesday and Thursday. Fire chiefs said people should report any signs of fire immediately by calling 999 and asking for the fire and rescue service.