Police are appealing for witnesses after a man was pushed onto the tracks by a fellow passenger at Buchanan Street subway station in Glasgow.
The 23-year-old victim was then punched after climbing back onto the platform.
The suspect was a white male in his 40s or 50s, who was thought to have been chanting football songs before he left the subway on Saturday evening.
British Transport police said the incident was an "extremely dangerous and violent assault".
Police said the suspect had "deliberately shoulder barged" the victim after leaving a train at Buchanan Street at 20:25 on 9 December.
They believe he was at the Rangers v Ross County match earlier that day.
He was wearing a black jacket, white shirt, black trousers and black shoes and had receding black hair. He was in the company of a woman and three men.
The suspect left the station after punching the victim.
Det Con Finlay Bruce, from British Transport Police, said: "This was an extremely dangerous and violent assault which could have had ended in tragedy.
"The victim could have been struck by a train or been seriously injured, or even killed, by the high voltage electrical lines. It is essential we trace the person responsible.
"What we know so far is that the suspect is believed to have been chanting football songs before he left the subway at Buchanan Street. Because of this, I believe he may have been at the Glasgow Rangers v Ross County match earlier that afternoon.
"I am looking to hear from anyone who was at the station at around 8.30pm and saw what happened. Likewise, if you know someone who matches this description, then I would urge you to contact BTP as a matter of urgency."