Why does the state of the Spanish railway network and its maintenance raise questions?

Following the collision of two high-speed trains in Urda on the Madrid-Seville line, Spanish media raises concerns about the outdated signaling system. Despite Spain investing over 55 billion euros in rail infrastructure from 1990 to 2018, much of the funding was allocated to new high-speed tracks rather than maintenance. This incident has sparked discussions about the state of railway maintenance in Spain.