British Transport Police (BTP) need help in tracking down individuals who attacked a woman in an Ealing Broadway station waiting room.
Officers have released CCTV images of four people they would like to speak to who may have information about the assault, which happened at 4.20pm on November 30.
PC Stacie Gross said: “The victim, a 45-year-old woman from Hayes, suffers from a pain in her ankle.
“We know several people at the station saw the incident, and I would appeal to anyone with information to come forward."
She added: “All passengers have the right to feel safe on the rail network and we will do everything we can to find the people responsible for this disgraceful attack.”
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference TSUB/B5 of 11/02/15.
Information can also be passed anonymously to Crimestoppers on 0800 555 111.