The death of at least 15 people following the derailment of one of Lisbon’s iconic funiculars on Wednesday threatens to upend knife-edge local elections scheduled for Oct. 12.

Current polling has incumbent center-right Mayor and ex-European Commissioner Carlos Moedas narrowly ahead of Socialist Party candidate Alexandra Leitão. But the odds could change in the aftermath of the disaster, which is raising questions about the funding and maintenance of the Portuguese capital’s public transit system.

In the immediate aftermath of Wednesday’s crash, employees belonging to Carris — Lisbon’s public transit authority — said they had repeatedly raised concerns about the safety of the city’s aged transport infrastructure, as well as the decision to subcontract maintenance of the funiculars to a private company in a bid to cut costs.

“There were successive complaints from workers regarding the level of tension in the funiculars’ support cables,” said Manuel Leal, head of the union representing the capital’s public transit workers. “There needs to be a thorough investigation into this disaster.”

Employees also linked the crash to wider budget cuts. Moedas was criticized by opposition politicians last year after it emerged that his administration had redirected millions of euros in public cash from Carris to finance the Web Summit technology conference. Municipal authorities later insisted that the public transit authority’s budget had not been altered because EU cash had been used to make up for redirected funds.

The crash took place in the late afternoon, when one of the cables that tows tram cars up the steep Glória hill snapped. The vehicle, which was carrying several dozen passengers, sped down the incline before smashing into a building at the bottom.

Authorities on Thursday said that nearly all the victims “have foreign last names” and are presumed to be tourists. In addition to the fatalities, the crash left 23 passengers seriously injured, five of whom are in critical condition. Following the disaster, Portugal’s government declared Thursday to be a day of national mourning, with two additional days of official mourning to be observed in the capital.

The Glória Funicular, in operation since 1885, was originally built to carry residents from the low-lying Rossio Square to Bairro Alto neighborhood, but as Lisbon has turned into a tourist mecca, foreign visitors have become its primary customers. It’s common to see long lines of influencers waiting to snap photos on its railway cars, which have been recognized as national monuments since 2002.

City authorities have provisionally suspended service on the capital’s five funicular lines while technicians review the infrastructure.