By Franz Kruger
BBC News, Johannesburg
Thabo Thedise knows his hobby is dangerous.
Train surfing involves different and often very dangerous moves
"Yes, I can fall, but I can phone my mom, she can take me to the doctor," he says.
The tall 19-year-old is one of Johannesburg's "train surfers": mostly young men who perform daring stunts on the city's commuter trains.
The most dangerous is train surfing proper, standing on top and dodging bridges and high-power cables.
Then there's a trick that involves swinging out of a door as the train travels through a tunnel and running along the sides.
The mildest, and most common, move involves jumping off the train as it begins moving, and jumping back on board again.
If he dies, so be it, Thabo says, to boisterous laughter from the crowd that surrounds him at central Johannesburg's Park Station. His mother is a member of a burial society who will pay for the funeral.
"They will cry and they will bury me. I will be a born again. You know anytime you are going to be born again. I might be a white boy."
The group disperses, laughing. "I have to go and attend to some chicks," Thabo says with a swagger.
Johannesburg's commuter trains have seen an upsurge in train surfing, partly because of the long-running security guard strike that has only just been settled.
Lebohang Motsamai, a strapping young man with hair braided tightly, describes another move, known as "gravul" from the gravel on the tracks: "I get under the train, when it is in motion, and kick the stones, kin, kin, I play with my legs."
Surrounded by a clutch of admirers, he says he plays these games to impress girls. "Because when I do this, they are going to love me. They are going to say, eish, this boy is clever."
The easiest manouvre is jumping on and off a moving train
Some miles away, Desmond Motsemme, 15, is lying in hospital. His arms are tied to the rails of his bed because he's become aggressive in his disorientation.
It's visiting time, and his doting grandmother and mother are there every day, talking softly and feeding him yoghurt.
After weeks in hospital, slowly mending, he can still hardly speak. He fell while swinging out of a train, trying to retrieve his cap that had flown off. The result: severe concussion, and most of his scalp ripped off.
His grandmother, Ruth Motsemme, says the injuries were terrible to see.
"I couldn't look at him, really, like that. The skin of the head was just off, from here to here, he was terribly swelling, and bleeding badly.
"It was upsetting me to look at him like that. I couldn't believe that boy would survive, it's a miracle that boy is alive."
Mrs Motsemme says she spoke to him about the dangers of playing these games just days before the accident, but nothing seems to help: "I said to him, please my boy, that is the train, it is steel, it is going to kill you."
Metrorail, the company that runs the commuter trains, says it is deeply concerned about the phenomenon.
The company keeps records of the accidents, injuries and suicides on its system, which transports over 500,000 people a day in the greater Johannesburg area.
Although the company won't release the figures, press reports about accidents have become a regular phenomenon.
Metrorail's manager of educational projects, Dolly Gaelesiwe, is charged with visiting schools to talk to the kids about how dangerous the trains are.
But she also finds it very difficult to get through to them: "You know, whenever I go to schools I say guys, I'm an aunt, granny, mother - to me every child is my child. I don't like what you are doing. Why are you doing it? It worries me a lot because you see these kids getting hurt every day. This is a national crisis, it is a real national crisis."
One person who thinks she has an idea of what fuels train surfing is Nonhlanhla Gasa, a social worker with the counselling and support group Childline.
She says that risk-taking is normal adolescent behaviour, but that it has a particular edge for kids from depressed communities.
"Nowadays there is a lot of things happening at home, domestic violence in communities, children's rights are violated left, right and centre.
"So children want to prove themselves, they want to attract attention in so many dangerous ways, from the people. It can be peer pressure, they want to see who is stronger than who."
Life is cheap, she says, and when the teenagers shrug off the possibility of death, it's not just bravado.
"For them life really doesn't matter. Most of the kids see dying as a way of resting from all these problems, from all these issues that life is throwing at them that they cannot take."
Now that the security guard strike is over, the incidents may become less frequent.
But the teenagers' delight in risk-taking is unlikely to disappear, and nor are the too-often disastrous consequences.