A mass scrap broke out on a train between Lincoln to Sheffield before spilling out onto the Gainsborough Lea Road station platform.
British Transport Police are appealing for information and witnesses to the brawl, which is believed to have involved some 20 people.
Two large groups began fighting on the Northern service at around 9.50pm on Saturday, January 27.
Staff were said to be quickly on hand to intervene and separate the two groups.
A British Transport Police spokesperson said: “Officers would like to speak to anyone who saw the incident, or thinks they may have information which could help.
“They are asked to please contact BTP by calling 0800 40 50 40 or texting 61016, with reference 682 of January 27.
“Alternatively, contact Crimestoppers anonymously on 0800 555 111.”