A teenager was threatened at knifepoint to hand over his wallet at Aber railway station.
British Transport Police said the robbery happened on Thursday, October 20, between 12.35pm and 12.56pm at the station on Nantgarw Road.
The 19-year-old victim arrived at the station via train and was walking down the station ramp towards Nantgarw Road when he became aware of a man who started to walk towards him from the bottom of the ramp.
The man bumped into the victim and threatened him with a knife and demanded he hand over his property.
The robber stole the victim’s wallet and the victim then ran towards Nantgarw Road.
Police have described the robber as white, around 6ft tall, of medium build, and aged in his 20s, with a brown beard. He was wearing a navy tracksuit and trainers.
Det Insp Jaci Thomas, of British Transport Police, said: “This robbery left the victim suffering from shock.
“It happened in broad daylight in a public place and it is likely that there were people around who may have seen or heard something, or saw the offender in the station around the time of the offence.
“I would like to speak to anyone who has any information about the incident.”
Anyone with information can call 0800 40 50 40 or text 61016 quoting reference 369 24/10/16. Information can also be passed to Crimestoppers anonymously on 0800 555 111.