The accident took place around 10.30am local time in the suburb of Palermo, when the seven-car passenger train collided with a maintenance train on the tracks of a railway bridge.

“The locomotive and first passenger car derailed,” the state-owned Trenes Argentinos (TA) railway company said in a statement.

Emergency authorities reported 30 people taken to hospitals after the crash, but city health officials updated that figure to 57 at the end of the day.

Two seriously injured victims suffered head trauma and were airlifted to hospitals by helicopter, emergency service official Alberto Crescenti said.

The majority of the other victims had been discharged by Friday evening, he added.

News photographs showed a train carriage ripped open at one end and tilted against the metal railings of the railway bridge. It was unclear if it was a carriage of the passenger or maintenance train.

The impact “was very strong,” a passenger in the last car told the TN news channel. “One person was thrown against the door, many people were thrown to the ground.”

“It is a miracle we are alive,” cried another passenger, as he leaned out of the window filming the accident scene, in images broadcast on several stations.

Transport minister Franco Mogetta said there were “multiple hypotheses” about what had happened, including whether something had gone wrong with the signalling system.

He mentioned complaints of “cable theft” amid a sharp rise in the pilfering of copper cables and those made of other metals, in a country where year-on-year inflation stands at almost 290% and 42% of the population lives in poverty.

The leader of the train drivers’ union, Omar Maturano, slammed the “de-financing” of Trenes Argentinos under budget-slashing President Javier Milei’s government.

“There are thefts of signalling cables. We have been asking for repairs for 10 days, but there are no spare parts for the signalling, or for the trains. We are told that there is no budget.”