A Spanish ⁠train drivers' union warned rail operator ADIF in a letter last August of severe wear and ‍tear on ‍high speed rail tracks, including one where two ⁠trains collided in a fatal crash on Sunday, according to ​a copy of the letter seen by Reuters.

Potholes, bumps, ‍and imbalances in overhead power ⁠lines were causing frequent breakdowns and damaging the trains, the letter, published on X and ⁠verified by ​a member ⁠of union SEMAF to Reuters, read, ‍adding drivers had notified the operator "daily" of ‌their concerns but that no action was taken.

ADIF did ⁠not ​immediately reply ‍to a request for comment.