The international TGV rail link between Geneva and France is interrupted until Sunday due to rail tracks that have been deformed by the hot weather close to the Swiss city.
Five TGVs planned for Saturday have been cancelled.
The problem was reported on Friday evening, blocking two high-speed trains and affecting some 150 passengers in Geneva.
Swiss Federal Railways (SBB/CFF) saidexternal link tracks at La Plaine in canton Geneva had buckled due to recent hot weather.
The track is currently being repaired but disruptions are expected until Sunday, it said. Passengers should contact SBB/CFF for the latest updates.
Users who already have train tickets for Saturday are asked to contact SBB/CFF to find a solution. For regional traffic, alternative buses are providing rail connections to Bellegarde in France. Two TGVs nonetheless were able to leave via the Swiss city of Lausanne on Saturday morning.
The end of June saw an intense heatwave in Europe which beat the previous record for the month set in 1999. France, Switzerland, Austria, Germany, the Czech Republic and Spain all registered new national highs for June, with the southern French town of Gallargues-le-Montueux recording 45.9 Celsius (114.6 Fahrenheit). The hot weather continued last week in Switzerland with temperatures in the 30s.
During the heatwave at the end of June, disruptions were reported between Geneva and La Plaine which had led to delays and train cancellations.