On 29 August at around 7.30pm a woman was sexually assaulted by a man onboard the 7.12pm service from Liverpool.
As the train reached St Helens, the victim reported the incident to the train guard who contacted police.
The man is believed to have boarded the train at Liverpool Lime Street and left the service at Wigan.
Detectives have made extensive enquiries into the incident and believe the man in the CCTV image may have information which could help their investigation.
If you recognise the man, or you were on the train at the time and think you may have useful information, please text 61016 or call 0800 40 50 40 quoting reference number 2100064227. Alternatively you can call Crimestoppers anonymously on 0800 555 111.
More news from Blackpool
