BERN - Rail jour­neys across the Swiss Alps will take longer for the next few months after a major derail­ment has left the record-break­ing 35-mile (57-kilometer) Got­thard Base Tunnel partially out of action. The world’s longest tunnel was closed last week when a freight train jumped the tracks, derailing 16 carriages and damaging about five miles of rail lines, Swiss national rail operator SBB said in a state­ment. SBB said the tunnel will reopen partially on August 23, with one of the two lines through the mountains unaf­fected by the incident. But the reduced capacity will mean re-routing passenger trains via a scenic railway that takes up to two hours longer until early 2024. “Until further notice, pas­senger trains will be diverted via the panorama route,” the SBB statement said. “The jour­ney time is extended by 60 minutes in national traffic and between 60 and 120 minutes in international traffic.” The company said it was examin­ing whether passengers could be safely transported with only one track in operation but for the time being it would be closed to non-freight traffic until further notice. Opened in 2016 after 17 years of construc­tion, the Gotthard Base Tunnel has become a vital railway link between northern and southern Europe, as well as a destination for rail enthusiasts wanting to traverse the world’s longest and – at almost 1.5 miles below the surface - deepest tunnel. The structure runs between Erstfeld on the northern side and Bodio in the south, connecting rail traffic between the Swiss city of Zurich and Milan in Italy.