British Transport Police have released a CCTV image following a report of a sexual assault on a train between Digby and Sowton and Exmouth railway station.
The incident happened between 5.45pm and 6.10pm on Friday 27 December.
A man is reported to have boarded a train at Digby and Sowton station before standing behind a woman and touching her inappropriately.
Officers would like to speak to the man in the image who may have information that could help their investigation.
Anyone who knows him is asked to contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference 1900113099.
Alternatively, call Crimestoppers anonymously on 0800 555 111.