The woman was on the platform at the station on Friday (December 5) at around 10pm when a man approached her and carried out the sexual assault.
As she moved away from him, he spat on her before boarding a train and leaving the station.
Over a month later, the British Transport Police have released an image of a man who officers would like to speak to, as they believe he may have information which could help their investigation.
Anyone who recognises him or who ha information is asked to contact British Transport Police by texting 61016 or by calling 0800 40 50 40, quoting reference 791 of 5 December.
You can also contact Crimestoppers anonymously on 0800 555 111.
