Extreme temperatures this week caused disruptions on Swiss Rail’s network.
The heat caused disruptions in Zurich Oberland, Aargau and Geneva, according to 20 Minutes.
The stretch of track between Meyrin and La Plaine, in Geneva was closed between midday and around 3pm and some high-speed trains bound for France were cancelled on Wednesday. Similar interruptions occurred on the S-Bahn line between Pfäffikon and Wetzikon in Zurich Oberland and between Wildegg and Brugg in Aargau.
According to Swiss Rail, the rails store heat throughout the day rising in temperature as the day progresses. Rail temperatures can climb as high as 70 degrees celsius. The heat causes the rails to expand and in some cases buckle. In most cases the expansion is absorbed by the sleepers and gravel.
Most tracks remain usable when buckling occurs. Train speeds are reduced however.
The risk of buckling can be reduced by using concrete rather than wooden sleepers and by painting rails white – a study by ETH Zurich shows how this can reduce rail temperature by 7 degrees.