An incident of racial abuse on a train is being probed by transport police.
Officers said a man got on the 7.55pm Helensburgh Central to Edinburgh service on Sunday October 2 and started to use his phone.
He went on to make comments about a nearby passenger which other people on the train perceived to be racist.
There was then an exchange of words between another male passenger and the man, who left the service at Carntyne station at 8.52pm.
The man, who boarded the train in Helensburgh, is described as white, aged between 55 and 65, with receding grey hair. He was wearing a green jacket, blue jeans and a grey checked shirt.
British Transport Police (BTP) officers are appealing for anyone with information to come forward.
Investigating officer Pc Mark Harrington said: “We would like to find out a bit more about what happened on the service as we know there was some kind of altercation between passengers following a phone call made by this man.
“We know other passengers were watching the incident and so may have crucial information.”
BTP can be contacted on 0800 40 50 40.