What the recordings reveal about the moments before impact
Conversations between the train control center at Atocha, in Madrid, and the drivers of the two trains involved in Wednesday's accident in Toledo province have emerged and offer clues about what happened. The audio, circulated by Spanish media, captures technical exchanges in the minutes before an AVE operated by the state company Renfe and an Iryo train collided from behind shortly before 09:00 local time, 08:00 GMT. The crash left at least 68 people dead and dozens injured.[S1][S2][S3][S4][S5][S6][S7][S8]
Prime Minister Pedro Sánchez ordered a thorough investigation, while Transport Minister Óscar Puente described what happened as an incident that occurred in an inexplicable manner. The exchanges between Atocha and the drivers suggest the AVE was cleared to proceed at full speed even though the Iryo convoy was having trouble restarting and remained stopped on the same track. The inquiries have only just begun and are expected to establish conclusions about the events.[S1]
A computer failure and two trains stopped south of Madrid
The accident happened on Wednesday morning after a computer fault disrupted normal train movements across a zone roughly 140 kilometers south of Madrid. Both passenger services were running the Madrid to Seville route. The Iryo train was a few kilometers ahead of the AVE when the widespread failure brought both to a halt. In the recordings, operators at Atocha can be heard taking charge of the situation and discussing what steps to take.[S1]
They were trying to work out how to get the trains past the area around Urda, in Toledo, where the LZB navigation system had failed. LZB is a continuous signaling and control system that monitors a train's speed and position in real time and can brake automatically if the driver exceeds safety limits. On the call to the driver of AVE train 2080, the controller dictated the instructions to follow, telling the driver to disconnect and reconnect the LZB and resume running under the BSL regulation system at normal speed. When the driver asked to confirm normal speed, the Atocha operator said yes.[S1]
BSL, the Bloqueo de Señalización Lateral, is a backup system in which safe separation between trains is managed through signals placed alongside the track. Meanwhile, in the communication between Atocha and Iryo train 6076, which was stopped about 30 kilometers ahead of the AVE near Urda, the driver told the control center operator that a transmission fault had prevented her from restarting. At 08:41 the Atocha operator instructed her to disconnect and reconnect the LZB system and resume under BSL at normal speed, and she acknowledged the instruction. The directions given to both drivers were similar.[S1]
Five minutes between the last exchange and the collision
In a later communication, however, the same driver warned that she had been unable to move forward. The Atocha controller simply told her to proceed as soon as she could. The time was 08:48, and the gap between the two trains was about 30 kilometers, a very short stretch if the AVE reaches the speed of up to 200 km/h authorized for that area. Five minutes later the AVE struck the Iryo from behind.[S1]
The communications imply that AVE train 2080 was authorized to advance even though Iryo train 6076 had not been able to fully resume running and was still having problems reconnecting to the LZB navigation system. That is why Spanish authorities find it hard to believe such instructions were issued instead of a different protocol for these contingencies. Puente said the decision to restart circulation without the safety system having been restored belonged to the control center, whose operators chose to resume movement in circumstances he called inexplicable.[S1]
Under the protocols, when the LZB system that manages high speeds fails, trains should proceed at a safety speed of no more than 40 km/h, which lets the driver keep a possible obstacle in view and have enough time to avoid it. That is not what happened.[S1]
