British Transport Police are appealing for information after a man punched a ticket inspector in the face.
The attack happened at around 6.25pm on Monday, March 13, on a train between Balloch and Singer.
The men – believed to be teenagers – were asked to leave the train due to not having purchased tickets.
One of them then punched the inspector twice in the head.
Although it only caused minor injuries, the victim was left very shaken by the incident.
Were you on the train or did you see what happened?
The offenders were both aged around 16-years-old. One was around 5ft 5ins tall, with short dark hair. He was wearing a blue hooded top and blue jacket, black gloves, bright blue jogging bottoms and black and grey Nike Airmax trainers.
The second offender was around 5ft 7ins, with a shaved head. He was wearing a grey hooded top, dark jacket, dark tracksuit bottoms and dark trainers.
Investigating officer Det Con David Merchant said: “We’re investigating this incident fully and are determined to catch those responsible.
“It is disgraceful to think that someone can be attacked simply for doing their job – and so, if you know the men who did this, I urge you to get in touch.”
Anyone with information is asked to contact BTP on 0800 40 50 40 or text 61016, with reference 465 of 13 March.