A normal day at the New Delhi railway station: a multitude of poor Indians, a few conspicuously wealthy travellers among them, push and shove to catch their trains.

Some distance from the hurly burly, in a room next to the police post, sit four scruffy boys, dazed by hunger and anxiety. They don't realise it yet but on this particular morning, the gods are smiling down on them. They have just been snatched from a probable life of cruelty, exploitation, drug addiction and abuse.

As they wandered the railway platforms, they were perhaps minutes away from being lured with the offer of a meal or a "hotel job", and forced to work as bonded labourers in sweatshops - or, if anecdotal evidence is to be believed, catamites. But Mohammed Abarar, a volunteer with Sathi (Society for Assistance to Children in Difficult Situation [ sic]), was scouring the platforms at which trains from the poverty-stricken states of Bihar and Uttar Pradesh arrive and glimpsed the boys among the throng.

"I can tell when a boy is travelling alone," says Abarar. "He looks unkempt, lost, abandoned, hungry and listless. I show them my ID first, tell them they can check it with a policeman, and ask them if they have run away from home."

The four boys had indeed run away from home - theirs dotted about the vastness of rural India.

Omair, 11, says he ran away from a madrassa to which his parents had sent him because the maulana beat him with a stick and he had to read the Koran for 10 hours a day. Poor Muslim families often send their sons to madrassas, partly to learn about their faith but also because it means the family will have one less mouth to feed.

Mumtaz, 13, says he wanted to buy a mobile phone and when a friend told him the only way to earn the money to do so was by working in New Delhi, he jumped on a train without telling his parents, planning to work for a month, buy a phone for 1,200 rupees (HK$140) and return home.

Ubesh, 10, says he was lured onto a train by a stranger who told him he would get the boy a good job in the Indian capital so that he could help his impoverished parents. The stranger gave Ubesh the number of a contact in New Delhi but when the boy tried calling, the number was dead.

Karan, 13, says he ran away to earn money to buy medicine for his father and elder brother, who are being treated for tuberculosis in a hospital in Varanasi, and to feed his seven-year-old brother. Their mother died many years ago. He has come more prepared than the others, with a T-shirt and a pair of trousers in a plastic bag and a little money in his pocket.

Abarar and five colleagues attempt to calm the boys. Every few minutes, Mumtaz's face contorts as he tries to hold back tears. Omair has a fixed look and Ubesh looks confused. Only Karan, the eldest, seems to have his wits about him.

Soon, Abarar will take the boys to the Sathi shelter, in Daryaganj, where the process of reuniting them with their parents will begin. Across India, tens of thousands of young boys - girls rarely run away - are not so lucky.

YOUNG BOYS RUN AWAY from home for all sorts of reasons: an alcoholic father; a vicious stepmother; fear of a scolding by a parent or teacher; because there is not enough food for the whole family and they want a job so that they can pull their weight. The decision is usually impulsive, says Pramod Kulkarni, founder of Sathi, and has dire consequences.

More than 65,000 children go missing in India every year, according to the National Crime Records Bureau, and only about 40 per cent of them are ever found. A few runaways have lived through years of captivity before finding freedom and telling their tale to the media but, in many cases, the only evidence a child ever existed is the passport-size photograph their parents gave to the police in the hope that it would help in their search.

Runaway children use India's vast railway network, fares on which are among the cheapest in the world, to get to the cities.

Kulkarni says that each day, about 25 children arrive at New Delhi railway station alone. The charity Railway Children estimates that a child arrives alone on a railway platform somewhere in India every five minutes.

India's railway stations are gigantic, chaotic and daunting. When they realise their dreams of a good job are not going to be fulfilled and they have nowhere to turn, runaways survive by begging, sweeping the platforms, selling discarded plastic bottles or stealing.

The station becomes home. Life on the platform, as American novelist Paul Theroux wrote in his Great Railway Bazaar, is a microcosm of India, because rural passengers turn the platforms into a village. For newly arrived runaways, an entire ecosystem is already in place: water is available for washing - taps are provided for the many passengers who have to wait for trains that could be delayed for days; children can often get away with resting inside coaches for a while; food vendors will throw them scraps, or families, waiting for delayed trains and cooking meals on oil stoves, will take pity and let them share their rice and dal; and the stations are well lit and equipped with toilets.

Child traffickers prowl the platforms, hoping to recruit runaways as labour for local embroidery sweatshops, roadside eateries or illegal factories. Abarar and his team - along with other charities such as Railway Children and the Salaam Baalak Trust - try to get to the children before the traffickers do. It's often a question of hours or a few days.

Those children who are not lured away nor helped by a friendly NGO can end up staying on railway platforms for months, falling prey to criminal gangs and being introduced to drugs or glue sniffing.

"A child on the platform never grows up - he just ages," says Kulkarni. "The longer the child stays on the platform, the higher the risk of abuse. Addiction, petty theft and odd jobs become part of daily survival."

That kind of life changes a child, and their former selves become ever-more distant.

"Usually, when a child has been on the platform for several weeks, it becomes difficult to revive the family bond," says Kulkarni.

Many Indians assume that runaways have fled violence or unhappiness but, while some have, Sathi's research shows that 90 per cent of the children found on railway platforms fled on an impulse, after a trivial incident - a teacher slapping them or a father's anger over poor exam results. They are usually more than happy to go back home once they realise they have made a mistake but many have neither the courage nor the means to return.

IT'S 1PM AND BEFORE they can be reunited with their parents, the lucky quartet in New Delhi enjoy a respite at the Sathi shelter, where the rooms are bare of furniture but there is a television, a laptop, DVDs, books, crayons and board games. And food.

The first thing the boys receive is a meal of spiced chickpeas and puris (fried Indian bread). They visibly relax as their anxiety recedes. They see other runaway children in the shelter who seem cheerful, and that reassures them.

They are given a day or two to relax, eat and sleep. The staff earn their trust by chatting with them and soon the children are ready to talk in a little more depth about their homes and what made them run away.

Those unfamiliar with the poverty of India might struggle to understand why some boys take flight over what appear to be petty issues but it must be understood that they have probably had little education; they do not possess the knowledge or intellectual tools with which to process information, weigh up pros and cons and make sensible decisions. When their father hits them, for example, there is often no one to turn to; their mother is probably exhausted from poverty herself and may well be on the receiving end of beatings, too.

"Some of their fears - a scolding or a father's anger - may seem like small fears to us, but they are big fears for them," explains Kamlesh Pandey, a programme officer at Sathi.

"It's not that the parents don't care about their child," says Kulkarni. "In the 17 years since I set up Sathi, I have come across only 2 per cent of parents who don't care. The others are concerned about their child but handle them wrongly."

That is why Sathi, which means "friend" in Hindi, offers counselling to parents who come to pick up their children. Once Sathi has contacted the police in the child's home village, officers visit the parents. Then the police and Sathi arrange the parents' visit to the shelter. The time between discovery and reunion is typically four to six days.

Once the reunion is over, Pandey and the team of counsellors, Manju Singh and Manisha Sahu, offer the mother and father some basic parenting tips.

"I tell them they cannot be angry with their children for smoking or drinking if they themselves smoke and drink," says Singh. "I try to make them consider other options. If a child like Omair hates the madrassa but they want him to be educated, then try the local government school. And don't, I tell them, compare your child's exam results with those of brighter children."

If they say they have no idea why their child ran away, she tells parents the reason is likely to be a lack of communication, playing Chinese whispers with them to demonstrate how easy it is for misunderstandings to arise.

"If a neighbour accuses their child of something, I tell them they must make it clear that they will support their child," says Sahu. "So many are scared of what the neighbours will say."

When contacted, 90 per cent of the parents come to fetch their child. Of the 10 per cent who don't, half are probably too sick or otherwise unable to travel and the other half refuse because their son is a serial runaway or a drug addict and they want to be rid of him.

"Where the child does not want to return and where we feel the home atmosphere is abusive or violent, we send them to government homes," says Kulkarni.

IT'S 3PM AND SMILES mix with tears at the shelter as parents and sons are reunited. The quartet watch as boys rescued earlier hug their parents. Mumtaz starts crying again. Abarar tousles his hair, telling him his turn will come.

One of the boys being reunited is 10-year-old Shibu, who helps his father make sweetmeats that are sold in a Hindu temple in Shahjahanpur, in Uttar Pradesh.

"That day, Shibu touched the sweetmeats without having bathed," says his mother, Mayadevi, a slight, thin woman in a purple sari. "His father was furious and slapped him twice. Now we have learnt that Shibu ran away in anger but we thought he had gone to the fields to relieve himself. Only hours later did we realise he wasn't there."

Shibu's father, Sunderlal, keeps hugging and kissing his son. An uncle, a younger man, has accompanied the parents on the 350km train journey to the capital, the farthest any of them have ever travelled. After the tears, Shibu grins.

"I won't do it again. I just want to go home quickly," he says.

It's one more happy ending in the Sathi office. But, as Pandey muses, it could so easily have been different. He is haunted by one of his early cases, that of a boy called Rajnish, who ran away from Bihar's Darbhanga district, and had been living at New Delhi railway station for six months. Since he had no precise address, Pandey made the train journey to Rajnish's home village with the boy. When they arrived at the local station, Rajnish said the walk to his village was 2km through fields and forests. It turned out to be a 10km walk, and it was dark.

At around midnight, they reached the boy's home. The house was filled with relatives. In fact, the whole village was awake.

"They were readying for Rajnish's funeral at dawn," says Pandey. "A local pandit [priest] had told the family that he had 'seen' in his mind the boy was dead so the parents were told to perform the funeral rites without a body."

The next day, 500 villagers turned out to worship Pandey "like a god".

Rajnish was lucky. In his six months on the railway platform, he had not stopped thinking of his family and had managed to avoid drugs.

LATER IN THE WEEK, Omair, Ubesh, Mumtaz and Karan are preparing to go home. Photographs are duly taken, fathers and sons unsmiling in all of them. But that's because the hugs and smiles materialised earlier, off camera.