The train surfing stunt went viral after someone filmed it and posted the dramatic footage online.
The three boys hopped on the back of the train at the Silverstream station in Upper Hutt.
"We waited in the bush until the train stopped and jumped on. We stopped at each station when the train stopped, had a rest and jumped back on," he said. The younger two boys got off before the 16-year-old, who stayed on the train for about 6km to Lower Hutt.
"I'd done it two times before that by myself but that's the longest I've ever done it," he said.
"I was tripping out because people on Facebook were recording it. I rang the other two and said 'We're on the news bro'. It was pretty mean."
But now he says his train-surfing days are over. "It's a free ride at least but I wouldn't want to go back to court. I was an idiot because I could have died."
As well as meeting a woman who lost limbs in a train accident, the teen has also apologised to KiwiRail.