British Transport Police is appealing for help from the public after a young girl was subjected to a frightening encounter at Swinton railway station in Rotherham.
The incident occurred at around 6am on Saturday, January 17.
Police said the young girl was waiting for a train when a man tried to engage her in conversation, before asking inappropriate questions.
He then began touching himself inappropriately over his clothing.
He is described as Asian, aged in his 30s, around 5ft 8ins tall and of slim build.
He had several metal teeth. He was wearing a black coat, trousers and beanie hat and was carrying a black rucksack.
Anyone with information is asked to contact police on 0800 405040.