3 graphics that explain how the train accident in Spain happened

Spain began three days of mourning this Thursday after the second high-speed train collision recorded this year.

Two trains collided on Wednesday morning near the town of Urda, south of Madrid, leaving at least 74 dead and many injured, in Spain’s worst train accident in more than a decade.

The President of the Spanish Government, Pedro Sánchez, promised a rapid response to address the causes of the deadly accident.

These are the 3 graphs that explain what happened:

1. Chronology of the accident: when it occurred

The accident occurred on Wednesday at 08:54 local time on a straight stretch of road about 140 kilometers south of Madrid.

Both trains had left Madrid’s Atocha station: the Iryo train left at 7:54 and the Renfe train six minutes later.

At 08:33, the security system that monitors the speed of trains fails, causing trains in the area to stop. The AVE stops near Mora; the Iryo, about 25 km further south.

According to reports, the AVE train is authorized to continue “at normal speed” and resumes its march at 08:43. Shortly after, it rear-ends the Iryo, which was stopped.

The Iryo train was carrying 147 people (146 adults and one baby). There were 397 passengers traveling on the Renfe one.

2. What was the possible cause of the accident

At around 8:30 in the morning, an automatic signaling system known as LZB suffered a failure.

This system’s function is to monitor the speed and movement of trains to help avoid collisions, maintaining safe distances between them.

The breakdown forced six trains to stop on a 69-kilometre stretch of track, including the two that were involved in the collision.

With the automatic system down, circulation began to depend on verbal instructions from the Atocha control center, which operates 24 hours a day. From the office, the Renfe train is authorized to resume its journey despite the failure in the signaling.

Transport Minister Óscar Puente called the decision “inexplicable,” pointing out that a red signal should have kept the train stopped, given that the Iryo service was still on the same track.

In another accident on the same high-speed line on January 18 of this year, 46 people died and nearly 300 were injured.

Reuters reported that the CEO of the company that owns Iryo, Fabrizio Favara, had warned the Spanish Senate three weeks ago about problems in the network’s signaling system.

Favara made these statements before a commission investigating two previous accidents on the same line.

3. How the trains turned out

The force of the impact caused two cars of the Iryo train to fall down an embankment, leaving them partially reduced to a mass of twisted remains.

With a death toll still provisional, the accident constitutes the deadliest railway disaster in Spain since the derailment that occurred in 2013 near Santiago de Compostela, in the northwest of the country, which claimed the lives of 80 people.

While an investigation is underway to determine the cause of the accident, questions have been raised about the maintenance of rail infrastructure and passenger safety.

Train services remain suspended between Madrid and Andalusia.

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