It happened at Portsmouth Harbour last Monday evening.
Two people have been arrested after a fight broke out at Portsmouth Harbour station last week.
One person was left with a fractured eye socket, broken nose and cheekbones after the brawl on the Monday night.
The 18 and 17 year olds, both from Portsmouth, were arrested on suspicion of GBH and ABH and have been bailed.
Detective Constable Phil Bibbings, the investigating officer, said: "Around 9.20pm, heated words were exchanged at the front of the station between a group of youths and two brothers who were returning from a birthday party with their mother.
"Upon reaching platform 1, a fight broke out between the two groups, leaving the brothers, age 21 and 26, injured.
"One of the men suffered a fractured eye socket, broken nose and cheekbones, and the other received cuts and bruising to the face."
"We have identified three men, who we believe to be from the local area, that we would like to speak to about the incident as we believe they hold key information. I would urge anyone who recognises the men, or knows their whereabouts, to get in touch."
Anyone with information should contact British Transport Police on Freefone 0800 40 50 40 quoting B7/LSA of 07/08/12 or the independent charity Crimestoppers, anonymously on 0800 555 111.