Four technical failures occurred before a deadly train crash in Spain that killed 69 people and injured about 50 others, according to an investigation by rail infrastructure operator Adif.

The failures involved problems with the LZB safety system, the train control centre, communication systems and electrical disturbances. These issues occurred before a Renfe train struck a stationary Iryo train near Urda, south of Toledo.

Spain’s Transport Minister, Óscar Puente, said the LZB system stopped working 170 times over the past year. However, he described this number as normal and said it matched the European average.

The investigation also raised concerns about decisions following the incident. A train controller reportedly allowed the stalled Renfe train to restart at speeds of up to 160 kilometres per hour, even though the Iryo train remained stationary. The Renfe train later reached speeds of up to 200 kilometres per hour.

The four technical failures have raised questions about railway safety and the circumstances surrounding the collision.

Following the tragedy, Prime Minister Pedro Sánchez declared three days of national mourning. Opposition politicians also criticised government spending on railway infrastructure.

Former Adif president Isabel Pardo de Vera said officials had planned an upgrade to the railway line but never carried it out. She also questioned maintenance, construction and railway operations.

Authorities are separately investigating Pardo de Vera over allegations involving public contracts. She denies any wrongdoing.

Investigators continue to examine the events leading up to the crash and the four failures identified in Adif’s report.