Video equipment will be installed on suburban passenger trains as a matter of urgency.
Transport Minister Pam Beggs today said she had ordered Westrail to bring forward its original schedule for installing the equipment after an incident on a train last Tuesday in which a gang of youths assaulted passengers.
"That type of anti-social behaviour is totally unacceptable and will not be tolerated," Mrs Beggs said.
"People who wish to annoy other passengers should know that the train driver is in radio contact with patrol officers and can alert them to any incident.
"The video equipment will continuously monitor each car and immediately record incidents on tape which may be used as evidence in the event of prosecution.
"It also will provide Transperth and Westrail with a highly recognisable list of trouble-makers."
Mrs Beggs said the cameras would not be visible to passengers so trouble-makers would not know whether they were being filmed or not.
"But they can be warned that each day from now, the risk of being filmed will increase," she said.
"All 86 cars will have video cameras installed."
The equipment and installation will cost about $300,000.