The train derailments that occurred on Friday in Lüscherz (BE) and Büren zum Hof (BE) are probably due to strong gusts of wind, according to the SESE. This type of accident is not unheard of in Switzerland. This has happened three other times since 1996.
An Appenzell train was overturned by strong winds near Wasserauen (AI) on January 19, 2007, Christoph Kupper of the Swiss Security Investigation Service (SESE) explained on Saturday in an interview published on the online portal of 20 minutes as well as on SRF radio. There were no passengers, only the driver had suffered a shock and bruises.
“We then installed an anemometer there, a device which precisely makes it possible to measure the speed or the pressure of the wind. When there is too much wind, the trains no longer circulate there”, continued the specialist. Thus, on Friday, the Railinfo service announced that the connection between Appenzell and Wasserauen was suspended between Weissbad and Wasserauen due to high winds.
Mr Kupper, whose team has regularly investigated train accidents in recent years, said another derailment due to strong winds took place in 1996 in the Bernese Oberland, hitting a railway vehicle de Wengernalp and injuring four tourists, and in 2018 in the Bernese Simmental, on the line between Montreux and Oberland. Eight people were injured there, most of them slightly.
Wind attack angle
The normal gap between the rails is 1.4 meters. On the sections where the two trains derailed on Friday, the difference is only one meter. “This difference may well have an influence,” said Mr. Kupper.
If having narrower rails can play a role, the specialist speaks above all of the angle of attack of the wind: “What is decisive is the exact way in which the wind hits the train”. While the wagons certainly weigh tons, they also offer a large attack surface. Also, strong gusts of wind are difficult to predict as they can be very different from place to place.
The course of the two accidents on Friday, which left fifteen injured, will be examined by the SESE. First, driving and weather data will be analyzed, explained Christoph Kupper. The two lines concerned were still closed on Saturday. Replacement buses are running.
The specialist added that already today, railway companies must carry out a risk assessment in the event of a storm. In such situations, an increase in risk is a “realistic scenario”.
“We recently discussed this issue with the Federal Office of Transport, which is the supervisory authority. We are in the process of laying out the basics.” New requirements for a driving ban in the event of strong gusts of wind are “to be examined”.
This article has been published automatically. Source: ats