Police were called to a train at Market Harborough station on Saturday, after an on-train fight between rival football fans.
Shortly before 8pm on Saturday, officers from British Transport Police and Leicestershire Police had to intervene at Market Harborough to break up the brawl.
The fight was between West Ham fans - whose side had won at Leicester - and Luton fans, on their way back from a draw at Notts County,
Both sets of fans had been celebrating; West Ham at avoiding relegation and Luton at promotion.
But a fight broke out, during which a bottle was thrown which struck a man on the head. The victim was taken to hospital where he received treatment.
An investigation is now underway to trace those responsible for throwing the bottle.
Witnesses are asked to contact BTP by sending a text to 61016 or by calling 0800 405040, quoting reference 594 of 05/05/2018.