Last month Europe endured a heatwave that registered some of the hottest days ever recorded. But the oppressive heat isn’t over yet. In the UK, temperatures reached 100.6 degrees, which is the hottest ever recorded in July (the previous record was 98 degrees). Travel is even being disrupted with Network Rail reporting several heat-related incidents along the railway and potential downpours set to inconvenience travelers even more.

The Rail Delivery Group, which represents train operators and Network Rail, said that 20 of 26 train companies had been affected by cancellations and speed restrictions, particularly in London and the southeast of the country. “We believe there could be roll-on impacts tomorrow,” said Robert Nisbet, director of nations and regions at the group, “because many of the trains will be in the wrong places, many of the rail staff will be in the wrong place, and it will take time to re-set, to stabilize the timetable again. We could see disruption up until the weekend.”

Passenger Vivienne Tsui was forced to wait in unbearable heat before her evacuation from a train, due to a power shortage. “It’s been unbearable,” she told the BBC, “like a sauna. I had to get out of my seat because I felt like I couldn’t breathe.”

The heat has caused Great Western to cancel trains to London, Cardiff, and Swansea, and delays and cancellations are expected for trips on the Gatwick Express, Great Northern, Couthern, and Thameslink rail networks. Other railways are even advising people against traveling at all.

Since the UK is not used to such high temperatures, some people are in danger of heat exhaustion, with the NHS encouraging plenty of hydration.