A woman was subjected to racial and sectarian abuse on board a train from Edinburgh.
The incident happened on Saturday on the 11.37pm ScotRail service between Waverley and Bathgate.
While at the Edinburgh station, a group of men got on the train and became anti-social and disruptive.
They were asked to quieten down by passengers, but ignored their requests.
One woman was targeted with racial abuse by one of the men, who used threatening words and sectarian slurs.
The man is described as white, aged in his 20s and with short hair.
British Transport Police (BTP) officers are looking to identify any witnesses who were on the service that evening.
Anyone with information can text BTP on 61016, call 0800 40 50 40, or ring Crimestoppers anonymously on 0800 555 111.