Human error was the final link in the chain of errors and omissions that led to the tragic train disaster in Tempe late Tuesday night.

The 59-year-old stationmaster of Larissa was arrested as the major suspect, and he was also named as the responsible party by three Hellenic Railways Organization (OSE) and Hellenic Train officials who testified.

He was arrested by police officers of the Larissa Traffic Department, which is responsible for the preliminary investigation. A case was lodged against him for the offenses of manslaughter by negligence and causing bodily injury by negligence.

He appeared before the city prosecutor and officers of the Hellenic Police (ELAS) to provide explanations.

He allegedly claimed that during his shift he gave an order to change the tracks on the railway network so that the two trains would not move on the same line but that the system apparently did not respond.

This version of events is supported by a photograph from the stationmaster’s logbook that shows he instructed the fatal Inter City 62 train to continue its journey to Neos Poros, apparently not knowing that the freight train was moving on the same piece of track right toward it.

A colleague reportedly said in an interview with the media that before the fatal accident another train had come to a standstill at Tempe. And that in order to move the stalled train to the nearest station there were changes to the tracks but the network was not later restored to its previous state.

Tellingly, the arrested man had only been appointed to the position of stationmaster a few months ago after a short training program. He had previously worked at posts in the organization.

Rescuers resumed a search on Thursday for survivors of Greece’s deadliest train crash, combing through the buckled and crushed remains of carriages that derailed and then caught fire in a disaster that killed at least 46 people.

The high-speed passenger train with more than 350 people on board crashed head-on with a freight train near the city of Larissa late on Tuesday, and hopes of finding anyone still alive in the wreckage more than 34 hours later appeared slim.

“It will be very difficult to find survivors, due to the temperatures that developed in the carriages,” 40-year old rescuer Constantinos Imamidis told Reuters.

“This is the hardest thing, instead of saving lives we have to dig out bodies.”

Many of the victims were thought to be university students returning home after a long holiday weekend, and officials said the death toll was expected to rise further. Scores were injured.

As Greece sought to process a tragedy that its prime minister blamed on human error, railway workers nationwide walked off the job on Thursday, saying successive governments had ignored repeated demands to improve safety standards.

The station master of Larissa train station was arrested on Wednesday as authorities probed the circumstances that led to the passenger train, en route to the northern city of Thessaloniki, colliding with another train carrying shipping containers coming in the opposite direction on the same track.

Greece sold railway operator TRAINOSE under its international bailout program in 2017 to Italy’s Ferrovie dello Stato Italiane, expecting hundreds of millions of euros to be invested in rail infrastructure in the coming years.

The Italian operation has responsibility for passenger and freight, and the Greek state-controled OSE for infrastructure.