At around 7.30pm on December 9, 2021, the victim was sat on her own opposite a group of four men on a train travelling between Meadowhall and Scunthorpe.
One of the men made a racially motivated comment about the victim.
Officers believe the man pictured may help their investigation.
If you recognise him, or have any information, contact BTP by texting 61016 or calling 0800 40 50 40 quoting reference 548 of 09/12/21.