A masked gang has been captured on video terrorising passengers onboard a train in Adelaide's northern suburbs.
The gang pulled the emergency brake to stop the carriage before unleashing a vandalism attack while concerned passengers watched on nervously.
The team were brazen and chillingly calm.
With a bandana covering his face, one of the gang sprays graffiti on the side of the train during peak hour at Elizabeth South station, with two masked mates looking on.
It's clear that passengers are rattled, but there is little they can do, although one woman can be seen banging on the window.
The graffiti attack went on for several minutes before the doors could close.
"It's not acceptable behaviour and we do absolutely feel for our passengers, but once the brake has been activated there is a checklist the driver has to go through before the train can move again," Transport Department spokesman Paul Kermode said.
Commuters in the area are increasingly worried for their safety, with one man saying he felt "insecure" on the train.
Police have not yet identified the three suspects.
They are currently reviewing CCTV footage from the station and are appealing for witnesses to come forward.
The vandalised train is being cleaned, with the Transport Department fearful of copycat attacks.
Anyone with information is encouraged to call Crime Stoppers on 1800 333 000 or report anonymously online.