Undercover officers deployed across Metro trains
BBC/Jim ScottA "Trojan horse" operation which will see undercover police travel onboard Metro trains is under way.
Plain-clothed officers from Northumbria Police will patrol routine services at different times of the day across Tyne and Wear.
They will be told to respond to crime in areas where reports from passengers are common or act on intelligence to catch those who are wanted.
Northumbria's Police and Crime Commissioner (PCC) Susan Dungworth said it followed the "success" of a similar scheme which used decoy buses in South Tyneside and Sunderland.
Some customers have told the BBC they feel unsafe travelling on certain parts of the Metro, especially during the night.
But operator Nexus said the system remained "safe" and "incidents are few and far between".
BBC/Jim ScottProject Shield will see specially trained officers board trains at stations across the network, co-ordinating with colleagues in ticket halls and platforms.
"We're looking for habitual offenders, knife carriers, anything like that we can pick up and detect early on," said Sgt Louise Page, of the Northumbria Police Metro Unit.
"Anything we see we think is a potential danger or something that's troubling is something we will deal with."
This also includes spotting those involved in anti-social behaviour, county lines drug dealing or vulnerable people falling into crime.
BBC/Jim ScottIn some recent cases, Metro trains have been vandalised with windows forcibly removed by criminals or defaced.
However, Mandy Francis, from Nexus, said incidents "generally happened where we don't have police or staff in vicinity to assist".
She said the operation would send a "stark message" to criminals they would be caught and face severe consequences.
The operation, which has funding secured for the next year, has been developed by the Labour-elected PCC.
Dungworth added since Project Shield came into force, anti-social behaviour on public transport had reduced by 37 per cent.
