Editing Gotthard Base Tunnel (section)

== 2023 freight train derailment ==
On 10 August 2023, a freight train heading north derailed inside the tunnel, damaging around 8km of tracks, 20,000 concrete sleepers, and a lane change gate that separates the tunnel's two tubes.<ref name=":4">{{Cite web |title=Bahnverkehr im Gotthard-Basistunnel unterbrochen |url=https://news.sbb.ch/medien/artikel/124073/bahnverkehr-im-gotthard-basistunnel-unterbrochen |access-date=11 August 2023 |website=SBB News |language=de}}</ref><ref>{{Cite web |date=10 August 2023 |title=Entgleisung im Gotthard - SBB: «Es ist das eingetreten, was wir nie gehofft haben» |url=https://www.srf.ch/news/schweiz/entgleisung-im-gotthard-sbb-es-ist-das-eingetreten-was-wir-nie-gehofft-haben |access-date=11 August 2023 |website=Schweizer Radio und Fernsehen (SRF) |language=de}}</ref> Both tubes were closed to traffic. Trains scheduled to use the tunnel were cancelled or redirected to the "panorama route" which added about one to two hours to journeys. Since the alternate route was unable to accommodate bi-level equipment, passenger capacity was reduced by around two-thirds.  

Experts from the [[Swiss Transportation Safety Investigation Board]] (STSB) were dispatched to the site to preserve and document evidence of the crash. Investigators found fragments of a wheel and signs of derailment several kilometers before the crash site. At the Faido station, they discovered a pile of derailed wagons. The STSB's mission is to determine the causes of accidents to ensure or improve safety, rather than to assign guilt or responsibility.<ref name=":2">{{Cite news |date=13 August 2023 |title=Le déraillement d'un train au Gothard a été provoqué par le bris d'une roue - Le Temps |language=fr |url=https://www.letemps.ch/suisse/le-deraillement-au-gothard-provoque-par-le-bris-d-une-roue |access-date=17 August 2023 |issn=1423-3967}}</ref>
The STSB believes that the derailment was likely caused by a broken wheel tread inside the tunnel. All fragments of the wheel were found, consisting of several large pieces.<ref name=":2" /> The cause of the breakage has not yet been determined. External influence or fatigue fracture are possible explanations. The wheel fragments will be subjected to metallurgical analysis to determine the cause.
Despite the broken wheel, the wagon was dragged by the train for several kilometers. At the switching point of the multi-functional station, where trains can switch between the two tubes of the tunnel, the wagon derailed, pulling more than 20 following wagons off the tracks.<ref name=":2" />

The tunnel's repair work was extensive. Originally expected to be completed by the end of 2023, it was announced in November 2023 that the repairs would not be finished before September 2024, with the tunnel operating at reduced capacity until then.<ref>{{cite news |title=Tagesschau |url=https://www.tagesschau.de/ausland/europa/gotthard-tunnel-126.html |access-date=10 November 2023 |date=2 November 2023 |language=de}}</ref> This was due to repairs requiring a complete replacement of seven kilometers of rails, including 20,000 sleeper blocks and their concrete foundations, a damaged lane-change gate, two high-speed switches and many other safety and operationally relevant parts.<ref>{{cite web |title=Gotthard-Basistunnel: Schäden gravierend, Normalbetrieb voraussichtlich ab September 2024 |url=https://news.sbb.ch/medien/artikel/124073/gotthard-basistunnel-schaeden-gravierend-normalbetrieb-voraussichtlich-ab-september-2024 |access-date=10 November 2023 |website=SBB News |language=de}}</ref> Freight trains were allowed to use the east tunnel from 23 August due to a temporary maintenance gate replacing the damaged one whilst passenger services remained rerouted.<ref>{{Cite web |date=11 August 2023 |title=Derailment closes Switzerland's Gotthard Base Tunnel |url=https://www.trains.com/trn/news-reviews/news-wire/derailment-closes-switzerlands-gotthard-base-tunnel/ |access-date=11 August 2023 |website=Trains |language=en-US}}</ref><ref name=":4" />

Freight capacity in the tunnel was gradually increased on weekdays, while passenger services saw expansion on weekends. In case of emergency, passengers would be evacuated through the other tunnel tube.<ref>{{cite web |title=Gotthard-Basistunnel: Schäden gravierend, Normalbetrieb voraussichtlich ab September 2024 |url=https://news.sbb.ch/medien/artikel/124073/gotthard-basistunnel-schaeden-gravierend-normalbetrieb-voraussichtlich-ab-september-2024 |access-date=10 November 2023 |website=SBB News |language=de}}</ref> Following the reopening of the undamaged northern third of the western tube, additional freight and passenger services were scheduled to use the tunnel, with a full reopening and a return to normal service commencing on 2nd September 2024.<ref>{{Cite web |last=Bovenizer |first=Noah |date=2024-09-02 |title=Gotthard Base Tunnel fully reopens 13 months after derailment |url=https://www.railway-technology.com/news/gotthard-base-tunnel-fully-reopens-derailment/ |access-date=2024-09-04 |website=Railway Technology |language=en-US}}</ref>