Tempi Crash Report Suggests Hazardous Cargo Sparked Deadly Blaze

The Greek newspaper Kathimerini on Wednesday unveiled new details from a draft report by the National Organization for the Investigation of Aviation and Railway Accidents and Transport Safety (EODASAAM) on the Tempi train disaster.

The February 2023 collision, which claimed 57 lives, remains one of Greece’s deadliest rail tragedies.

Two years later, its impact

According to the preliminary findings, there is no evidence to support theories of a hidden freight car or a massive tank of hazardous material aboard the commercial train.

However, experts believe the final report will confirm that the third freight car contained between 3.5 and 4 tons of a volatile substance, most likely aromatic hydrocarbons. It is this cargo that is suspected to have ignited upon impact, fueling the inferno that followed.

Aromatic hydrocarbons are organic compounds composed of carbon and hydrogen, characterized by stable ring structures, such as benzene, toluene, and xylene. They are highly flammable and commonly found in fuels, solvents, and industrial chemicals.

Investigators have also sought to clarify the causes of the explosion. One key finding dismisses speculation that silicone oils leaking from transformers in the first two freight cars could have triggered the blast. The report notes that these transformers suffered only minor cracks, making it improbable that they played any role in the intense fire.

Yet, the exact nature of the explosive substance remains a mystery. Authorities have enlisted scientific teams from the University of Pisa, the University of Ghent, and the Swedish Institute to conduct further analysis. While they have yet to reach a definitive conclusion, all three institutions agree that computational fluid dynamics (CFD) provides the best framework for reconstructing the fire’s development.

Their final conclusions will depend on an accurate assessment of environmental conditions at the time of the crash, including wind speed, humidity, and temperature.
The draft report reconstructs the events of that night with striking precision. It details how, within six milliseconds of the collision between the two locomotives, an electric arc caused a short circuit. Three milliseconds later, an explosion erupted at ground level, possibly sparked by the braking system.

The blast sent a fireball shooting upwards, expanding to a diameter of 42 meters and burning with ferocious intensity for about two seconds. Shortly after, a secondary fire ignited at an unspecified location away from the main blaze.

This fire quickly doubled in size, a development that suggests a large quantity of fuel was involved. The third phase of the fire saw two separate blazes take hold—one near the freight train’s locomotives, where silicone oils may have been heated, and another in the wreckage of the passenger train’s dining car. The latter burned fiercely for nearly two hours.

A particularly haunting detail emerges from the University of Ghent’s analysis of the flames. The fire in car B2 of the passenger train began at 11:35 p.m. from its lower section and rapidly spread through its entire length. With no firefighting intervention, the blaze fed on seat fabrics, curtains, and other flammable materials until the carriage was completely consumed.

The draft report also breaks down the collision into three distinct phases.

The first and most violent impact involved the first four cars of both trains—the two locomotives from the freight train and the locomotive and first-class carriage of the passenger train.

The sheer force of the head-on crash flung the carriages into a nearby highway wall, obliterating the first-class section. Investigators reveal that an emergency brake was activated just one second before impact, while the passenger train’s automatic braking system engaged due to a sudden loss of pressure caused by the collision.

The second impact proved equally catastrophic. The dining car of the passenger train collided with a freight car carrying steel plates, crushing the dining car into a twisted mass resembling the Greek letter “final sigma” (ς). In the third phase of the crash, the remaining cars continued to collide with diminishing force until they finally came to a stop.