British Transport Police are investigating reports of an alleged homophobic abuse aimed at a member of rail staff on a train between Sleaford and Heckington.
The incident happened at 6.10pm on Thursday, October 14, when a train conductor asked a male passenger to see his ticket.
The man refused to show the conductor his ticket, and as he was leaving the train, he made homophobic slurs towards the conductor, according to British Transport Police.
Officers believe the man in the picture may have information which could help with their investigation.
If you recognise him or have any information about the incident, contact BTP by texting 61016 or calling 0800 405040, quoting incident number 512 of October 14.