A man suffered "significant head injuries" when he was attacked at Johnstone Railway Station.
The victim was hit from behind and cracked his head on a pavement during the senseless assault, which happened on Friday night around 7.15pm.
British Transport Police have launched hunt to trace the violent attacker and appealed for witnesses to come forward.
A Britsih Transport Police spokesman said: "The victim was struck on the back of his head which caused him to fall and bang his head on the pavement. The victim is currently in hospital being treated for significant head injuries.
"Officers are appealing for anyone who witnessed the incident, to come forward to assist the investigation.
"The suspect is described as a white male with short dark hair, around 5ft 6inches tall, wearing a Fila jumper with white writing, red cuffs and white stripes down the arms, and white tracksuit bottoms. The suspect also had a black bag.
"Anyone with information can contact BTP by texting 61016 or calling 0800 40 50 40 quoting reference 473 of 26/02/21.
"Alternatively they can call Crimestoppers anonymously on 0800 555 111."
