Greek prime minister says 'human error' is to blame for a train collision that left 43 dead

At least 43 people are dead, and 57 have been hospitalized after a passenger train and a freight train collided on Tuesday night (local time) near the city of Larissa in Greece, according to local authorities.

Rescuers are still maneuvering through twisted wreckage, searching for survivors on Wednesday morning.

By midday, with hope fading, investigators had begun turning to what caused this crash. The country's prime minister said in a televised address that "human error" was essentially to blame.

How did the trains collide?

According to the national rail operator, the passenger train was carrying roughly 350 people at the time of the collision, travelling at high speed from Athens to Thessaloniki, Greece's second-largest city.

Local Press reported that many of those passengers were students returning from Carnival, a three-day festival that precedes the religious season of Lent. According to Greece's public media agency, ERT, the freight train was likely carrying construction material, such as heavy steel plates.

Though the trains appeared to be travelling on a double-track line, both trains appeared to be moving on the same track, heading towards each other. The trains collided head-on, just before midnight local time, as the passenger train was exiting a tunnel under a highway in the municipality of Tempe.

Local media reports citing survivors suggest that the first two carriages of the passenger train were sent flying into the air, twisting backward and catching fire, leaving them entirely disintegrated by morning.

The remaining line of carriages buckled and slid off the tracks, sending dozens of dazed people escaping into the dark.

What is the death toll?

As of Wednesday morning, rescue workers were still sorting through the mass of metal, searching for signs of life.

More than 150 firefighters and paramedics are on the scene, said Greek Fire Service spokesperson Vassilis Varthakogiannis in a media briefing. The crews use cranes and construction equipment to help move some of the heaviest chunks of steel.

Most survivors of the crash were bused to Thessaloniki, where police took names to track the missing, Varthakogiannis said.

Greece's firefighting service said 57 people remained hospitalized late Wednesday, including six in intensive care, the Associated Press reported. More than 15 others were discharged after receiving initial treatment.

Greek authorities said at least 43 people had died. Still, the toll is expected to rise as more victims are identified, a task that's been complicated because temperatures exceeded 2,300 degrees Fahrenheit when fires broke out in the first three carriages.

Greece's prime minister has declared three days of national mourning.

What do we know about the cause?

In an address to the nation Wednesday, Prime Minister Kriakos Mitsotakis announced the formation of a cross-party committee of experts to investigate the causes of the collision.

Mitsotakis said the committee would explore "perennial delays" in critical railway projects but that "everything shows the drama is due, unfortunately, largely to tragic human error."