Greek rail workers have gone on strike in response to a tragic rail collision that killed nearly 60 people late Tuesday.

The head-on collision between a passenger train and a freight carrier on Greece's busiest route between Athens and Thessaloniki has triggered a time of national mourning in the country.

The death toll rose to 57 and more than 50 individuals are still hospitalized, the majority of whom were in the central Greek city of Larissa. Several are in critical condition.

But, as the tragedy's aftermath settles, Greek citizens are demanding answers.

In a statement, the rail workers' union said, "Pain has turned into anger for the dozens of dead and wounded colleagues and fellow citizens." 

The railway employees' strike began at 6 am and was scheduled to extend all day. The Athenian subway and national rail services have been interrupted.

Around 2,000 protesters gathered in the northern Greek city of Thessaloniki on Thursday as authorities admitted failures over a deadly train crash on Tuesday, police said as quoted by AFP. 

The protest saw stone-throwing and the use of Molotov cocktails but "calm has now returned," said a police spokesman in Greece's second city.

Left-wing organizations staged two different rallies in central Athens, one of which resulted in skirmishes between stone-throwing youths and riot police. Protests also took place in Thessaloniki and Larissa.

Following the incident, Transportation Minister Kostas Karamanlis resigned, and officials began a judicial investigation to investigate how two trains drove in opposite directions on the same track for more than ten minutes without anyone sounding the alarm.

On Thursday, the Larissa station manager was charged with seven charges of manslaughter and causing serious bodily damage via negligence. His identity has not been revealed.

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