A woman was racially abused on a train as it approached Lancaster station, say British Transport Police.
The incident happened on board the 11:43am Virgin trains service from London Euston to Glasgow Central, on Friday October 6.
Police say that as the train was approaching Lancaster railway station at around 3pm, a woman made racist comments towards another female passenger.
A man challenged the offender and she then swore at him.
Officers would now like to speak to the woman shown in the CCTV images as she may have information which could help the investigation.
If you recognise her or have any other information about the incident, please call 0800 40 50 40 or text 61016 quoting reference number 190 of 09/11/2017.