By David Willey
BBC News, Rome
Italian rail travellers have faced unexpected delays in recent weeks because of an increase in the theft of copper wire along train tracks.
High copper prices have made wires on railways tempting to thieves
Hundreds of trains in Rome and Turin have been delayed for at least 30 minutes as signalling equipment and safety devices have become disabled.
Italy's railway operator says that some 250,000 commuters have been affected.
The price of copper has tripled in the past three years, making it an attractive commodity for thieves.
Usually operating at night, they have been tearing up miles of copper wire running along rail tracks.
The wire is used to carry information for automatic signalling and safety equipment.
Police say they have arrested 22 people in the past month alone on charges of stealing copper wire.
Many of the accused have been identified as Romanian immigrants.
Near Turin, police discovered a clandestine factory allegedly used for recycling the metal ready for export.
The copper is being sold mainly to China.
In Naples, police recently seized dozens of sea containers filled with stolen copper coils parked in the port area ready for shipment to China.
The copper thieves have also been stealing copper cables belonging to the Italian electricity company Enel and stored at building sites.