British Transport Police are urging a man who was threatened and abused on a train from Mount Florida station to get in touch.
The incident - described as an alleged hate crime - happened on Wednesday on the 8.35am Mount Florida to Glasgow Central service.
A man on board the service is saifd to have hurled homophobic abuse at the victim, then threatened violence when the train reached Glasgow Central.
The man police want to speak to is described by witnesses as slim, 5ft 8ins, with short dark hair and wore a grey jacket. He was travelling with a woman.
Investigating officer PC Caroline Irving said: “We will not tolerate any kind of hate crime on the rail network and we take every report of this kind of behaviour seriously.
“I am keen to speak to anyone who may have been travelling on the service at the stated time who may be able to provide some information about the incident.
“I would like to speak to the victim of this incident and reassure him that we will do everything we can to investigate.”
Anyone with any information should contact British Transport Police on 0800 40 50 40 or text 61016 citing reference 371 of 12/05.