A £1,000 reward has been offered after thieves caused disruption on the Tyne and Wear Metro system by stealing cables.
Thousands of commuters faced delays getting to work on Monday after 80m-90m of cable was stolen at around 2am near the Stadium Station in the Felling area of Gateshead.
The reward has been offered by operators Nexus for information which leads to the arrest and conviction of whoever was responsible.
Pc Ryan Walker, of the Metro Unit, said the thieves put their own lives at risk.
He said: "People are in effect handling live wires which could leave them seriously burned and injured."
Chris Carson, Metro Services Director, said offering the reward was an "unprecedented step".
He said: "Metal theft is very rare on Metro because we have worked closely with police to crack down on criminals, and reduced the amount of metal cables we use as lines are modernised.
"But one attack like this is too many and we are determined to do all we can to help the police in its investigation."