A stationmaster accused of causing Greece's deadliest train disaster was charged with negligent homicide and jailed pending trial Sunday, while Prime Minister Kyriakos Mitsotakis apologized for any responsibility Greece's government may bear for the tragedy. An examining magistrate and a prosecutor agreed that multiple counts of homicide as well as charges of causing bodily harm and endangering transportation safety should be brought against the railway employee. At least 57 people, many of them in their teens and 20s, were killed when a northbound passenger train and a southbound freight train collided late Tuesday north of the city of Larissa, in central Greece. Also Read: Bangladeshi killed in Greek train crash The 59-year-old stationmaster allegedly directed the two trains traveling in opposite directions onto the same track. He spent 7 1/2 hours Sunday testifying about the events leading up to the crash before he was charged and ordered held. “My client testified truthfully, without fearing if doing so would incriminate him,” Stephanos Pantzartzidis, the stationmaster's lawyer, told reporters. “The decision (to jail him) was expected, given the importance of the case." Pantzartzidis implied that others besides his client share blame, saying that judges should investigate whether more than one stationmaster should have been working in Larissa at the time of the collision. "For 20 minutes, he was in charge of (train) safety in all central Greece,” the lawyer said of his client. Also Read: Death toll from Greece train crash rises to 57 Greek media have reported that the automated signaling system in the area of the crash was not functioning, making the stationmaster’s mistake possible. Stationmasters along that part of Greece’s main trunk line communicate with each other and with train drivers via two-way radios, and the switches are operated manually. The prime minister promised a swift investigation of the collision and said the new Greek transportation minister would release a safety improvement plan. Once a new parliament is in place, a commission also will be named to investigate decades of mismanagement of the country’s railway system, Mitsotakis said. In an initial statement Wednesday, Mitsotakis had said the crash resulted from a “tragic human error.” Opposition parties pounced on the remark, accusing the prime minister of trying to cover up the state's role and making the inexperienced stationmaster a scapegoat. “I owe everyone, and especially the victims’ relatives, a big apology, both personal and on behalf of all who governed the country for many years," Mitsotakis wrote Sunday on Facebook. "In 2023, it is inconceivable that two trains move in different directions on the same track and no one notices. We cannot, we do not want to, and we must not hide behind the human error.” Greece's railways long suffered from chronic mismanagement, including lavish spending on projects that were eventually abandoned or significantly delayed, Greek media have reported in several exposes. With state railway company Hellenic Railways billions of euros in debt, maintenance work was put off, according to news reports. A retired railway union leader, Panayotis Paraskevopoulos, told Greek newspaper Kathimerini that the signaling system in the area monitored by the Larissa stationmaster malfunctioned six years ago and was never repaired. Police and prosecutors have not identified the stationmaster, in line with Greek law. However, Hellenic Railways, also known as OSE, revealed the stationmaster's name Saturday, in an announcement suspending the company inspector who appointed him. The stationmaster also has been suspended. Greek media have reported that the stationmaster, a former porter with the railway company, was transferred to a Ministry of Education desk job in 2011, when Greece's creditors demanded reductions in the number of public employees. The 59-year-old was transferred back to the railway company in mid-2022 and started a 5-month course to train as a stationmaster. Upon completing the course, he was assigned to Larissa on Jan. 23, according to his own Facebook post. However, he spent the next month month rotating among other stations before returning to Larissa in late February, days before the Feb. 28 collision, Greek media reported. On Sunday, railway unions organized a protest rally in central Athens attended by about 12,000 people according to authorities. Five people were arrested and seven police officers were injured when a group of more than 200 masked, black-clad individuals started throwing pieces of marble, rocks, bottles and firebombs at officers, who gave chase along a central avenue in the city while using tear gas and stun grenades. In Thessaloniki, about 3,000 people attended two protest rallies. Several of the crash victims were students at the city’s Aristotle University, Greece’s largest, with over 50,000 students.. The larger protest, organized by left-wing activists, marched to a government building. No incidents were reported at that event. In the other, staged by Communist Party members at the White Tower, the city's signature monument, there was a brief scuffle with police when the protesters tried to place a banner on the monument. “The Communist Party organized a symbolic protest today in front of the White Tower to denounce the crime in Tempe, because it is a premeditated crime, a crime committed by the company and the bourgeois state that supports these companies,” Giannis Delis, a communist lawmaker, told The Associated Press.