Investigators suspect a 2022 switch to cheaper, uncertified cables may have led to the fatal tram derailment in Lisbon.
Shocking New Findings
In 2020, Carris, the operator of Lisbon’s trams, purchased a 32mm steel-core cable certified for passenger transport, costing €7,783. This cable met European standards, offering high resistance to compression, elongation, and long-term durability under repeated bending. However, in March 2022, Carris opted for a 43% cheaper fiber-core cable without certification, which, despite similar theoretical strength, degraded faster under bending—exactly the conditions faced by Lisbon’s trams. This change, made just before the current Carris president took office, was reportedly driven by cost-saving measures, according to the Portuguese newspaper “Pagina Um,” which obtained the purchase invoices.
Unsuitable Cables for Passenger Transport
The difference between steel and fiber-core cables was critical to safety: while fiber-core cables were more flexible and affordable, they were not designed for passenger transport and lost strength more quickly at stress points. According to the Portuguese newspaper, the use of the fiber-core cable led to the September 2025 tram derailment, which resulted in 16 deaths and injuries to over 20 people. Investigators had previously determined that the cable snapped, causing the tram to derail and collide with a building. Carris refused to release documents related to the purchases, citing ongoing investigations by authorities, and attempts to contact the cable supplier have so far been unsuccessful, journalists reported.
Investigations and Aftermath
Following the disaster, Lisbon’s authorities declared a national day of mourning. The city appointed an expert panel, including Carris representatives and other institutions, to develop a new safety system for the Gloria tram. Meanwhile, Portuguese media reported earlier incidents involving the tram that did not result in injuries, with Carris repeatedly assuring that inspections were conducted as scheduled. Incidents reportedly occurred as early as May 2025. The tram has remained closed since the September 3 disaster pending an investigation and necessary repairs.
