The train guard challenged a woman who was travelling on a used train ticket.
The woman became aggressive to the member of staff, verballyÂ abusing her and then pushing her on the cheek.
Officers believe the woman shown in this image may be able to help them investigate.
If you know who she is then contact British Transport Police by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 644 of 17/10/2018. Or ring Crimestoppers anonymously on 0800 555 111.
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A spokesman for BTP said: 'Violence and verbalÂ abuse against members of staff who are simply doing their job will never be tolerated. We are working hard to investigate this incident and to ensure the person responsible is brought before the courts.'