The theft of copper cables caused major disruptions to high-speed train services between Madrid and Andalusia, with thousands of people being stuck on trains overnight.
As per multiple outlets, the Spanish authorities began an investigation into the theft which Transport Minister Óscar Puente called a "serious act of sabotage."
However, by Monday morning, Puente said train services were "fully restored" and running again.
"Operations are now fully restored after a very difficult night for commuters... and staff, who had to respond under extremely complex circumstances," the transport minister said.
How copper cables were stolen and their role in train safety
As per the local media, the locations where the copper cables were stolen were situated in areas that could be reached through forest paths.
These cables played an important role in helping the system track the location of trains.
This disruption happened just a week after Spain and Portugal faced a blackout which caused trains to stop.
The authorities, including the civil guard and police, are investigating the incident to determine what happened and to find the individuals responsible for the theft.
The value of copper has significantly increased in recent years, which has led to a rise in the theft of copper cables from train and telecommunications networks.
People are stealing these cables because the high price of copper makes it a valuable commodity to sell.