[Source: Reuters]

Greek Prime Minister Kyriakos Mitsotakis called it an unspeakable tragedy but questions are being asked whether the fatal collision of passenger and freight trains on Tuesday night could have been prevented.

Nearly 24 hours after the two trains collided in central Greece, killing at least 36 people and injuring dozens, survivors and relatives of victims were still in the dark on who was responsible for Greece’s deadliest train crash in living memory.

Carriages travelling in opposite directions on the same track smashed into one another some 220 miles north of the capital Athens, at speeds some media reports put at up to 160 km (100 miles) an hour, reducing the passenger train into a mangled mass of steel.

There have been widespread media reports electronic signal software was not working, meaning signalling was done manually. Labour unions complain of chronic staff shortages.

OSE, the country’s state-owned operator for rail infrastructure, did not respond to calls requesting comment nor did it issue a statement. The transport minister, who earlier Wednesday burst into tears while visiting the disaster site, tendered his resignation.

Within hours, Greek police had arrested the station master at a provincial train station, accusing him of death through negligence. The 59-year-old denied the charges, attributing the accident to possible technical failure.