A flasher is being hunted by transport police after exposing himself to train passengers.
The pervert struck on a Northern service from Colne to Blackpool South at around 7pm on Thursday, May 10.
A public appeal was made this afternoon.
A 50-year-old woman got on the train at Preston, and the man 'then sat in front of her and exposed himself in front of other passengers,' British Transport Police said.
The woman got back off the train and informed station staff at Preston, but the flasher fled the station, the force added.
"Officers would like to speak with the man shown in the CCTV image as he may have information which could help the investigation," a statement said.
"If you recognise him, or have any information that could assist us with our enquiries, please call 0800 40 50 40 or text 61016 quoting log reference 595 of 10 May."