How the deadly train crash in Spain unfolded – explainer

Spain has begun three days of mourning to commemorate the 69 people who died in a high-speed rail collision. The trains – one from Spain's state-owned Renfe and the other from the private rail company Iryo – were heading from Madrid to to the southern region of Andalucía on the same line when they collided. The deadly crash came just 10 months after 46 people were killed when two trains collided on the same line. The disaster has raised fresh questions about safety on Spain's large, modern high-speed rail network. The Guardian's Laure Boulinier explains how it unfolded