On 28 February 2023, a head-on collision occurred between two trains south of the Tempe Valley in Greece, about halfway between the Greek villages of Tempi and Evangelismos in the Thessaly region. The collision, follow-up derailment and fireball that ensued involving the InterCity 62 (IC62) passenger train operated by Hellenic Train and an intermodal freight train, killed 57, heavily injured 81 and lightly injured 99 people. The estimated number of people were 352 on the passenger train including 10 staff, and 2 staff on the freight train totalling 354 people on both trains. It is the most serious railway accident in Europe since 2013, when a train derailment in Santiago de Compostela killed 79 people.
Vigils, angry protests, and clashes with the police occurred throughout Greece following the crash. Beginning on 2 March 2023, railway workers of Hellenic Train and the Athens Metro went on strike to protest the dangerous conditions related to the crash. Following the crash, Transport Minister Kostas Karamanlis resigned, taking responsibility for the crash and for his failure to bring Greek railways to 21st-century standards. However, he was reelected after standing for office just two months after the incident.
The investigation has so far implicated 43 state officials – those directly responsible for the accident, such as the station master and Hellenic Train officials, but also those who failed to carry out the necessary upgrades to the system (European Train Control System and centralized traffic control). Accusations have also been made against officials from the Ministry of Infrastructure who manipulated the site of the accident with "landfilling" that followed the completion of the rescue operation. However, the trial is still a long way off (estimated at the end of 2025), with hundreds of petitions pending for the investigating judge to consider. The development of the investigation process has been closely followed by the Greek press, while private investigations by the relatives of the victims and through independent institutional bodies, such as the bar associations, collecting evidence to support the criminal accusations, are an unprecedented phenomenon for Greek society.
On Tuesday 28 February 2023, the InterCity (IC) 62 passenger train, consisting of an electric locomotive and 8 carriages, departed from Athens railway station at 19:30 EET with Thessaloniki railway station as its final destination. The train carried 431 passengers, most of them students in their 20s returning after the long weekend of Carnival celebrations and Clean Monday.
At 21:00, freight train number 63593 consisting of two electric wagons and 13 flatcars loaded with sheet steel and shipping containers – with a total weight of 618 t and a length of 259 m – departed from Thessaloniki, bound for the OSE freight station at the Thriasio plain.
Upon the arrival of the IC 62 at Palaiofarsalos station the service was interrupted for almost an hour after a fault in the electrification system forced it to wait for its repair. This fault was one of the causes of the accident as it forced the station master to make constant track changes.
The train departed from Palaiofarsalos station at 22:40 moving until its entrance to the Larissa railway station area, on the southbound track as only on this track the electrification had been restored. Just before the train entered Larissa station, the switchman returned the train to its correct, northbound track. The train disembarked 82 passengers and departed at 23:04, with a delay of 48 minutes.
In order for the train to reach the next station, Neoi Poroi, three points had to be set to straight ahead. The stationmaster successfully set the first point, but missed the next two. Specifically, the tracks remained in the diverted position as they had been placed to accommodate the movement of the previous suburban passenger train 2597, which was operating on the Larissa–Thessaloniki line. As a result, the passenger train left the correct line (north) and at about 23:06–23:07 entered the opposite line (south), where the freight train was already located. The stationmaster, believing he had made the necessary turnouts, gave the locomotive driver movement authority towards Neoi Poroi, while ordering him to ignore the color light signal (red) as it was out of order permanently. The driver of the passenger train realised that he was on the southbound track and requested a repeat of the instruction. The instruction was repeated and the course continued.
For 12 minutes and 18 kilometres the freight train, which was travelling at a speed of 90 km/h and the passenger train, which was travelling at a speed of approximately 150 km/h, were running on the same line until at 23:20, at the height of Evangelismos, both trains collided head on.
The head-on collision between the two locomotives caused them to derail and be diverted. The two locomotives of the freight train were thrown to the left and hit the wall of the adjacent A1 motorway, while the passenger locomotive and the first coach (A1) were deflected off the tracks and crashed to the ground, completely destroyed.
The other wagons continued to move, but activation of the brakes (manually by the driver of the freight train, automatically by the air brake of the passenger train) significantly reduced their speed. Immediately afterwards, the wagon restaurant (K) collides head-on with the front of the platform carrying the sheet metal. The wagon is deformed into an S-shape and lands on the wreckage of the locomotive and the first wagon, which together have been reduced to an amorphous mass. This is followed by the derailment of the third wagon in the line (B2), which hits the ground, bends and is cut into two pieces, with the rear end lifting up and hitting the fourth wagon (B3).
At the moment of collision, when the electrified carriages hit the traction current pylon along the track, two electric explosions are generated. The first one when the locomotive of the passenger train collides with the pylon of the descending line, the second and bigger one when the electric freight locomotive collides with the pylon of the ascending line.
Sparks appear to have ignited spilt liquid fuel and created the initial fireball. This fireball, which lasted for 2 seconds and was on its way to dissipation, was refuelled by a second fuel release, which renewed and fed the fireball for a further 4 seconds, doubling the size of the phenomenon (the first fireball was 40 m in diameter, the second 80 m). The fireball created a very large heat load for the structures and occupants within its radiating area.
After the fireball is extinguished, three pool type fires continue their destructive work. The first fire breaks out near the locomotives of the freight train, fueled by silicone oil spilt around, and burns at low intensity for an unknown amount of time. The second fire flares up underneath the dining car, consuming the last remaining fuel in the fireball, and fed by other fuels such as silicone oil from the engines, it continues to burn with great intensity for about an hour. This fire became so intense in the first 30 minutes that the first attempt to extinguish it at 00:02 (43 minutes after the fire started) by a single fire engine had little to no effect. The third fire broke out from an unknown source under carriage B2. Initially of low intensity, it burned the 16-metre-long car to the ground in 40 minutes.
The cause of the formation of the flash fire and the subsequent fires is still under investigation, as opinions differ.
According to the findings of the Hellenic Fire Service, Hellenic Train and the forensic experts who investigated the scene of the accident at the request of the prosecutor, fireball was caused by the second electric arc, which ignited the silicone oils in the transformers of the two locomotives, which leaked into the environment. Specifically, it is claimed that "the fire that broke out immediately after the collision of the trains, was caused by the electrical discharges generated by the cutting of the power cables of the electric locomotives with a nominal voltage of 25,000 volts, combined with the spraying of the cooling oil of the power transformers of the locomotives generated during the collision".