British Transport Police also release image of man they wish to talk to
The incident happened on board the westbound train on 20 August.
British Transport Police say that during the journey, a man sat next to a woman, touched her and himself and exposed himself.
Officers believe the man shown in this image has information which could help their investigation.
If you know him contact BTP by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 653 of 20/08/2018.
You can also ring Crimestoppers anonymously on 0800 555 111.
BTP say tackling all forms of unwanted sexual behaviour on public transport is a priority and they have worked hard in recent years to send a clear message to victims that they will be taken seriously.
September 13, 2018