A freight train derailed in the Gotthard Base Tunnel on Thursday. The Swiss Federal Railways said the tunnel would remain closed until August 16 at the earliest.
Until then, train passengers between German-speaking Switzerland and Ticino will be diverted via the Gotthard panorama route, which takes about an hour longer.
Cancellations are also possible, the federal railways said. This could disrupt the traffic of people returning form their holidays and going to the Zurich Street Parade, which is taking place over the weekend.
The train derailed at a multifunction point in Faido, in canton Ticino. This multifunction station is one of two emergency stops of the tunnel.
Cantonal police announced that several wagons had derailed, some of which contained dangerous goods. However, these did not pose any danger and nobody was injured.
The federal railways said the causes of the derailment and the extent of the damage were still unknown. "The damage is considerable," spokeswoman Roberta Trevisan told Swiss public broadcaster, RSI.
As far as passenger transport was concerned, she recommended travellers find out more before driving through the separate Gotthard Road Tunnel.
Experts will now examine the damage and check for possible damage to the roadway. The Swiss Safety Investigation Centre is also looking into the matter.