FIRST ON 7: Shocking video shows the new risks taken by Sydney teenagers involved in a type of train surfing called 'coupler riding'.

The dangerous stunt - where 'riders' hang on between the carriages and its coupler - can have a fatal conclusion.

Footage obtained by 7News shows commuters boarding a train when one passenger jumps off, and decides to risk his life by riding on the outside.





Authorities are warning that the behaviour is incredibly reckless, dangerous, and stupid.



"It's a one-way ticket to death, paralysis, or amputation," Transport Minister Andrew Constance said.

"We are going to clamp down. We're going to get these results and stop this kind of moronic behaviour across the network."



The trend has claimed lives in Melbourne where a young carpenter was electrocuted when he hit overhead wires.



The dangers to those surfing the trains are obvious, but they also place drivers at risk.

In an accident they are often the first to attend and some struggle to recover from what they see.

"It's also incredibly reckless in that it dramatically affects other people's lives," Rail, Tram and Bus Union spokesperson Bob Newham told 7News.

"If they do fall off - someone has to go and clean that up. Those people can be scarred for life from the effects of that."



Penalties for trespassing on secure areas can include, fines of up to $5,500, jail time or worse.