Anojan Gnaneswaran was found injured at Strawberry Hill station just after 11.50pm on January 8.
The 21-year-old was pronounced dead at the scene shortly after.
Two men, aged 19, and a 18-year-old man, have now been arrested in connection with the investigation.
Previously, two men, aged 19 and 20, and a 15-year-old boy were also arrested in connection with the incident.
They have all been released under investigation.
A 16-year-old boy was also arrested but has been released on police bail.
Senior investigating officer, Detective Inspector Paul Attwell said: “We have now arrested three people in connection with the death of Mr Gnaneswaran. I would like to take this opportunity to thank the members of the public who have come forward with information to support this investigation.
“We continue to appeal for anyone with that hasn’t been in touch already to reach out as soon as possible, via this link , or by texting 61016 or calling 0800 405040 quoting reference 630 of 08/01/24.
“In particular, I am urging for those who live in the vicinity of the train station who might have seen or heard something, or captured something on their CCTV, dash-cam, doorbell footage between 11pm on 8 January and 12.15am on 9 January to get in touch.
“Alternatively, you can call Crimestoppers anonymously on 0800 555 111.”
A short time later, a 16-year-old boy was also found injured after a stabbing in Alexander Close, Twickenham.
This is the same 16-year-old who was arrested.
Officers and London Ambulance Service crews attended and found a boy with a slash in his leg.
His condition was assessed as not life-threatening.
Police are treating the two incidents as related.
A spokesperson for British Transport Police said: “Two men aged 19 and one man aged 18 have been arrested in connection with an investigation into the death of a 21-year-old man at Strawberry Hill railway station.
“The 21-year-old victim can now be named as Anojan Gnaneswaran, from Twickenham. “His family have asked for privacy at this time.
“Previous updates: A 19-year-old man, 20-year-old man, and a 15-year-old boy have all been released under investigation. A 16-year-old boy has been released on police bail.”