Year 9 pupil Sam Connor handed over his mobile phone and school bag to other kids before they watched in horror as he was struck at 4pm on Monday at Chertsey station.
The platform had been packed with children and adults from the catholic Salesian school when the tragedy happened.
Police were then called and were forced to clear them away so that a specialised team could take Sam’s body away.
A pal of Sam’s reportedly said that he was being bullied and would sit on his own in the playground during breaks.
“Sam was being bullied at school but I don’t know how, lots of children are bullied but it must have been horrendous for him to resort to this”Family friend
A family friend told The Sun: “Sam was being bullied at school but I don’t know how, lots of children are bullied but it must have been horrendous for him to resort to this.”
It is believed that a hand-written suicide note was found nearby.
Sam was said to be “bright and popular” by pals and he was one of the “nicest and most charming” boys at a local breakdancing club.
A friend wrote on Facebook that he was “heartbroken”.
He said: “Cannot even think of an emotion to describe how I am right now apart from just heartbroken. No parent should ever have to bury their own child. The child should always bury the parents.
“The crying with happiness, the laughs, the dancing will never be the same without you. Rest in peace Sam you absolute legend.”
“Breaking isn’t going to be the same with you gone. Hope you’re still dancing out there in the skies.”
A boy said how Sam went onto the track.
He told the Daily Mail: “It’s horrible. I have friends who were there and saw the whole thing.
“(He) handed his bag and phone to his friends and then lay down on the track in front of the train.
“Some of the older pupils were really good – they held everyone back and made sure everyone else was safe.
“They said he was being bullied. It’s only four days until school breaks up and you’d have thought he’d be able to get help.”
A shop worker said how “children were running around crying and screaming”.
One passenger told how other pupils were calling out Sam’s name after he was hit.
He reportedly said: “I thought maybe one of the kids had dropped their phone as they were all looking down at the wheels of the carriage.
“We saw some of the girls starting to cry; we saw some of the boys leaning down, literally on their knees, calling down between the train and the tracks, calling ‘Sam, Sam’.”
A school spokesman reportedly said they had “no record” of Sam being bullied while headteacher said the school was “devastated”.
An educational psychologist and counsellors are at the school to support students who need help.