BTP officers are appealing for further information following a fight on a train between Preston and Blackburn stations.
The incident happened at 8pm on Saturday, July 27.
It is believed to have involved fans from Burnley and Blackburn Football Clubs.
A large of number of men, suspected to have been involved in the fight, were ejected from the service at Blackburn.
The train was the 7.21pm Blackpool North to York service
Officers would like to speak to anyone who witnessed the incident.
Witnesses can contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference number 547 of 27/07/19.