Nexus, the public body which owns and manages the Tyne and Wear Metro, and Northumbria Police have issued a joint statement in light of the major incident on April 30 where a group of youths threw the trolley at a moving train from the footbridge at Monkseaton Metro station.
It comes at a time when there are more anti-social incidents being reported on Metro trains and at stations.
Martin Kearney, Chief Operating Officer at Nexus, said: “There was a serious incident on Saturday where a shopping trolley was thrown from a footbridge and landed on the roof of a passing Metro train.
“This was completely unacceptable and it was fortunate that nobody was seriously injured or even killed.
"It was a dangerous act and lives were undoubtedly put at risk as the trolley could have gone through a window or caused a derailment.
“We are working closely with Northumbria Police to pinpoint the offenders so that they can be brought before the courts.
“The incident was more evidence of a problem with anti-social behaviour that goes wider than just Metro.
"It is affecting communities, and some of that offending is in areas where we run our services.
“We are doing all we can to deter disorder on Metro, which is fundamentally a safe transport system for people to use.
“Nexus expects to spend £1.5m on a dedicated security team to deter troublemakers, and we have invested £4m in new and improved CCTV across the network.
"We have stepped up visits to local schools to highlight the dangers of misbehaving on the railways and to encourage kids not to get involved in crime and disorder.
"Every year we see in the region of 16,000 young people across hundreds of local schools.
“We will never accept any level of anti-social behaviour on Metro and we continue to work closely with partners to prevent and eradicate this behaviour.
“Anyone who causes trouble on the Tyne and Wear Metro faces prosecution, heavy fines, and even a ban from the network.
"If anyone has information about the incident which occurred at the weekend I urge them to contact Northumbria Police.”
Supt Sam Rennison, from Northumbria Police, said: “We are investigating a report from Saturday evening of a shopping trolley being thrown onto the Metro service at Monkseaton.
“I want to be very clear that this sort of behaviour is totally unacceptable and extremely dangerous.
“We have a number of enquiries under way to identify those responsible, and we would urge anyone with information to come forward.
“We will continue to work closely with our partners, including operator Nexus, to tackle pockets of disorder when they occur and prevent incidents from happening.
“This includes increasing our presence around transport hubs, while building on our existing dedicated operations to tackle anti-social behaviour.
“As we continue to see passenger numbers increase, we are committed to playing our part in helping ensure people can have a trouble-free journey.”
Anyone who has any information in relation to the incident should contact Northumbria Police, online through their website or by calling 101 quoting reference NP-20220501-1120.
Information can also be shared anonymously, with independent charity Crimestoppers on 0800 555 111.