Fiveteen centimeters from death. One arm, a girl hangs off the back of a train at speeds up to 115 kilometres an hour, even posing for photos. She's joined by four boys, all showing no regard for their lives. Across the network, they repeat their actions and get caught in the act. What's your reason for trying certain? We might find something. I'll give you a hint. It's in Melbourne. What's in Melbourne? Your house. You live in New York. And there anything but a polygetic. It's completely our decision. And if we want to risk our lives doing that, then that's what we're going to do. Members of the group call sky high idiots hide behind masks and don't what their identities reveal. If you're proud of what you do, why do you hide behind the face mask. So don't have to pay it fine. Metro has slammed these actions as dangerous and risky but they're also deadly. In four years, three train surfers, Joshua Green, Jordan Porter and James Wilkinson, have But in the past year, only 10 train service have been penalised, but many more are defying public condemnation. And while the fine is $389 for adults, it's only $78 for those under 18. Police are now considering using the latest CCTV technology to monitor events on trains in real time. Members of the group say they're not phased by the police attention, the penalties, or even the threat of a crackdown. Instead, they insist they'll continue to post more videos in an act that's thumping their noses with authorities. Parents aren't really too thrilled about it, but it's not going to stop us. Is anything going to stop you? Not really, unless it's death. This group is now under police investigation. Jonathan Kursley, 9 News.