Rail travel and extreme heat

Extremely hot weather takes a toll on rail infrastructure—which is why we’re always thinking ahead to give you a safe, pleasant journey.

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Preparing for extreme heat

When temperatures spike, rail infrastructure can suffer. Embankment fires are more frequent, track begins to buckle, catenaries can be pulled down, and air conditioning and electronic systems can malfunction. But with the right planning, we can avoid many of these risks.

Curious? Watch our video below [in French] and read on to learn how we work to keep our passengers safe and comfortable during heatwaves.

Les pannes, l’été, c’est une fatalité ?

  • 1.5 M

    bottles of water were distributed to passengers in summer 2020

  • 100% of TGV and INTERCITÉS, 96% of TERs and 63% of Transilien trains are air conditioned

Your safety and comfort are our priority

Extreme heat can affect your comfort and even your health, so we keep you informed and take special steps to make travel easier when temperatures soar.

If the temperature rises above 35°C, Météo France sends SNCF a weather alert, and we relay it to you across a variety of media. We also encourage passengers to take special care of themselves and others while travelling with us.

  • Stay hydrated: drink plenty of water throughout your travels. Depending on the length of your journey, plan to bring one or more bottles of water with you. If there’s an incident on your line, we may launch our Distib’eau plan, which calls for distributing the non-alcoholic beverages in the café bar to the passengers who need them most, especially if your train is without air conditioning for over an hour.
  • Stay informed: SNCF station employees and your train manager can recommend the best course of action.
  • Stay alert: be aware of the people around you in the station and aboard your train, especially children, seniors and others at high risk. If anyone feels unwell, please alert your train manager or the nearest SNCF station employee.

Priority stations

When a weather alert is in effect, priority stations have the technical, human and logistics resources they need to service a train within ten minutes. This includes providing support for passengers, alerting information volunteers and activating our local civil defence partners. SNCF currently has around 30 priority stations.

Hot topic: How heatwaves affect trains and railway infrastructure

We monitor our rail network closely year-round, but in summer, we work even harder. Night and day, SNCF employees keep watch over our tracks to identify areas where hot weather could cause problems.

Aboard our trains, it’s natural for electrical and electronic components to heat up, but extreme summer temperatures can make them even hotter. And that can cause malfunctions or breakdowns—especially if the train’s air conditioning system can’t cope.

Extreme heat and sudden, sharp temperature swings can also be hard on railway infrastructures such as track, catenaries and signalling systems, and hot weather increases the risk of embankment fires, especially during droughts.


Railway tracks are 95% steel: high temperatures make them lengthen and expand, and if the change becomes too pronounced, trains have to slow down.

View the video below [in French] to learn more about how extreme heat affects track—and what we’re doing to keep you safe when you travel with us.

Power supply cables

To work properly, the overhead cables that supply power to our trains must remain straight and horizontal. Systems of pulleys and counterweights usually keep them taut, but when temperatures spike, the counterweights drop and the cables can lengthen and droop.

View the video below [in French] to learn more about how extreme heat affects catenaries—and what we’re doing to keep you safe when you travel with us.

Pourquoi ralentit-on les trains lorsqu'il fait très chaud ?

Signalling systems

Heatwaves can cause the electrical and electronic components in our signalling systems to fail, so we’ve installed air conditioning in areas where the most sensitive equipment is housed.

Embankment fires

The areas around our tracks are more likely to catch fire when temperatures are high, especially during droughts.

65 °

is the highest temperature our electronics can take

Maintaining our rolling stock and infrastructure

We’re constantly thinking ahead to prevent heat-related incidents, and we participate in France’s nationwide Plan Canicule (heatwave plan), which has gone into effect every summer since 2003. Special measures include:

  • carrying out targeted pre-summer maintenance on all trainsets between April and June. This includes checks on all air conditioning systems.
  • organizing “heat patrols” by SNCF employees to monitor infrastructure conditions, including track temperature and catenary tension systems. The timing and frequency of these patrols are based in part on data from Météo France, the French national weather service.
  • inspecting areas around tracks and removing brush to limit the risk of fire in hot, dry weather.

Depending on the reports from our patrols, we may take the precautionary step of reducing train speeds.

Air conditioning hotline

Since 2008, our Charentes Périgord Technicentre has operated a technical support hotline staffed by some 60 air conditioning specialists, including a six-member emergency-response team. Thanks to their expertise, most AC problems aboard our trains can now be solved remotely.

Information hotline

For more information on heatwaves and their impacts, call Canicule Info Service at 0 800 066 666 (no charge within France). From outside France, dial +33 8 00 06 66 66.