Argentina train crash: Full investigation promised
Argentina's authorities have promised a full investigation into the train crash in Buenos Aires that killed 50 people on Wednesday.
Hundreds more were injured when the packed commuter train smashed into the buffers as it came into a station.
The government says it will join the victims as a plaintiff in a legal action against the private company that runs the line.
The auditor-general said the accident followed years of safety failings.
He has said the concession to run the line should be taken away from the company, Trenes de Buenos Aires (TBA).
The company has blamed government price controls, saying that keeping fares down has made it impossible to fund improvements to the line and rolling stock.
Transport companies receive government subsidies in order to keep ticket prices low.
TBA has promised full cooperation with the investigation and expressed its deepest condolences to the victims.
Since privatisation in the 1990s, public transport has been subisided by the government to keep ticket prices low.
The driver of the train is in intensive care and has not yet explained why he could not bring it to a halt as it came into the Once station during the morning rush hour.
The aging front carriages crumpled like concertinas in the collision, leaving the dead and wounded trapped in the twisted wreckage.
Ten of the 50 dead were from other South American countries - five Paraguayans, two Bolivians two Peruvians and a Chilean.
Planning Minister Julio de Vido confirmed that the government would be joining the legal action against train operator TBA.
"The president has instructed the planning ministry to present ourselves as a plaintiff in court in order to defend the public interest," he said.
"This is basically to be with the victims, whether they are the injured or relatives of the dead, which will present themselves as plaintiffs."
Amid allegations of corrupt relationships between senior officials and TBA, Mr de Vido insisted there would be no cover-up.
"We want it to be clear that neither the former President [Nestor] Kirchner nor the current president have shown that there are mechanisms of protection for anyone in situations like this," he said.
The judge who has been appointed to lead the investigation has a wealth of evidence to examine, including CCTV footage of the moment of impact.
Auditor-general Leandro Despouy said safety failings on the line had been revealed in a 2008 report, but had not been addressed.
"The conditions are in place for the state to proceed to rescind the concession," he said.
The same line - Sarmiento - was the scene of another accident in September 2011, when 11 people died as a train hit a bus crossing the tracks and then collided with another train.
Wednesday's accident was Argentina's worst train crash since February 1970, when a train smashed into another at full speed in suburban Buenos Aires, killing 200 people.
Correction 27 February: Adding line to make it clear that transport companies receive government subsidies to keep prices low.