The headteacher of the school where 16-year-old Ajmol Alom attended has sent several pictures of the "star pupil" to ITV London.
Chris Dunne, headteacher at Langdon Park School, said he had a "very bright academic future ahead of him".
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The victim ran along the platform with his friend when the attacker pulled out a knife and chased them both.
Spray cans were found near the bodies on tracks near a south London station.
Some 81% of passengers are satisfied with their journey, down three percentage points from spring 2017.