A victim of the deadly train collision at Tempi filed a criminal complaint against the Hellenic Railways Organization (OSE) at the Athens prosecutor's office on Friday, demanding the full investigation of the accident.
Filed through court lawyers, the complaint calls for investigating the criminal liability of every person in a position of responsibility at OSE, related companies, and every politician who acted in a supervisory role for OSE.
According to the complaint released to the media, the plaintiff is a woman.
It is expected that the criminal complaint will be tabled in the Greek Parliament, which is responsible to judge whether any politicians are criminally liable and if so, how.
Meanwhile, Greek police fired tear gas and protesters hurled firebombs on Thursday as more than 40,000 people took to the streets to slam the government and voice outrage at last month's train disaster that killed 57 people.
The protests were accompanied by a 24-hour strike -- the biggest yet since the disaster -- this time called by Greece's leading private as well as public sector unions.
Clashes erupted at Syntagma Square near parliament in Athens, where police fired tear gas and stun grenades at demonstrators hurling firebombs and rocks.
As protesters retreated, they smashed traffic lights and shop windows and set rubbish bins on fire, AFP reporters said.
A plainclothes police driver for a leftist MP was lightly hurt a demonstrator smashed his car window, said state television ERT.
Ten people were detained for questioning, police added.
The February 28 train crash exposed decades of safety failings in Greek railways and has put major pressure on the conservative government ahead of national elections.
Police said 25,000 people protested in Athens on Thursday, as well as around 8,500 in each of the country's next largest cities, Thessaloniki and Patras, where brief clashes also broke out, police said.
Thursday's industrial walkout shut down the civil service, flights and ferries.
'Things have to change'
Many protesters urged the government of Prime Minister Kyriakos Mitsotakis to resign over what is the country's deadliest rail accident.
"This crime will not be forgotten," demonstrators from the country's communist union PAME chanted as the crowd marched towards parliament and the offices of rail services company Hellenic Train in Athens.
Students shouted "murderers" and marchers threw flyers of Mitsotakis wearing a stationmaster's cap, captioned "it's everyone's fault but mine".
The rail disaster occurred shortly before midnight when a passenger train crashed head-on into a freight train in central Greece after both were mistakenly left running on the same track.
Most of the passengers were students returning from a holiday weekend.
"Things have to change in this country, we simply cannot mourn all these deaths," said Athens' protester Stavroula Hatzitheodorou, in reference to deadly wildfires that have gripped Greece in recent years as well as the train crash.
"We hope that things will change in these elections," Hatzitheodorou, who works in the private sector, told AFP.
A stationmaster and three other railway officials have been charged, but public anger has focused on long-running mismanagement of the network and the country has been rocked by a series of sometimes violent mass protests.
Last week, some 65,000 people took part in demonstrations around the country, including around 40,000 in Athens.
In addition to the 57 people who were killed, several victims remain in hospital, including one passenger who is fighting for his life.
The Italian state-owned company operating rail services in Greece, Hellenic Train, said those hurt in the accident and the families of the dead would each between 5,000 and 42,000 euros ($44,600) "to cover immediate needs."
"This is in no way an admission of responsibility" the company stressed late Wednesday.
The father of one passenger who died rejected the offer.
"We don't want their money... this was mass murder, I refuse to accept an apology from murderers," Pavlos Aslanidis told Alpha TV on Thursday.
"Had this been a serious country, everybody at the transport ministry would be in handcuffs," he said.
Greece's transport minister resigned after the crash and Mitsotakis has sought to soothe public anger by repeatedly apologising and vowing a transparent probe.
Rail traffic ground to a complete halt across the country after the accident, although acting Transport Minister Georgios Gerapetritis said this week that services would gradually resume from March 22.
Gerapetritis said a report by experts investigating the tragedy will be delivered in a month's time.
Investigators have separately opened a probe into possible railway funds mismanagement over the last 15 years.
Gerapetritis and former transport ministers will appear before a parliamentary committee next Monday to answer lawmakers' questions on the tragedy.
READ MORE: "Serious safety faults in rail network," says Greek watchdog.