The 28-year-old man was in his cab, when he was approached by a man in his 50s, who attacked him.
It happened as the 5.11pm Milngavie to Motherwell service had just stopped at Bearsden station on Sunday July 27.
The driver was taken to the Western Infirmary and released following treatment.
The suspect had short gray hair, glasses, and was wearing a blue t-shirt and grey trousers.
Detective Constable Jim Duncan, the BTP officer in charge of the inquiry, said: "Members of rail staff should be able to carry out their duties without encountering such despicable behaviour.
"I am appealing for anyone who was on the train or at the station and can help the man responsible to contact BTP."
Anyone with information is asked to contact British Transport Police on 0800 555 111.