A man in a penguin costume and his father were punched and kicked by a group of thugs after they asked if he was a Tottenham fan.
Before he used the toilet, he was asked by one of the men if he supported Tottenham, police said.
The victim’s father, a 56-year-old man, approached them and tried to pull the victim away, at which point they were both attacked by the group.
The men punched and kicked the father and son, with the disorder spilling out on to the platform at Chelmsford station.
As another member of the public tried to intervene he was also assaulted. He sustained a black eye.
That father and son were left with multiple cuts and bruises to their faces and bodies.
The incident happened between 11.50pm and 12.25am on December 21.
Officers have released CCTV images of people they would like to speak to as they may have information which could help the investigation.
If you recognise them, or have any other information which could help, please call BTP on 0800 40 50 40 or text 61016, reference number 228 of January 9 2018.