British Transport Police (BTP) officers said the group is believed to have information that could help their investigation into the “serious incident” on a Metropolitan line train on March 16.
According to police, at around 6.40pm that evening, two Asian men were headbutted, called racial slurs and verbally abused as the train travelled between Wembley Park to Northwood Hills.
A group of Liverpool football club fans is believed to have been involved in the incident, described by police as a racially aggravated assault.
CCTV images of nine men police would like to talk to have now been released.
Earlier that afternoon, Liverpool lost to Newcastle by two goals to one at Wembley stadium in the Carabao Cup final.
Anyone who recognises these men or has any other information is asked to contact British Transport Police by texting 61016 or by calling 0800 40 50 40, quoting reference 2500031833.
Alternatively, you can call Crimestoppers anonymously on 0800 555 111.
