A man has come forward following a British Transport Police re-appeal regarding an assault on board a train at Milton Keynes in November.
CCTV footage of the incident was released on Monday, March 16.
A 29-year-old man, from Milton Keynes, made contact with BTP the following day and will be interviewed by officers in due course.
PC Alex Trivino, investigating, said: “I would like to thank the members of the public who came forward with information.
“I would also like to thank local media for publicising this appeal.”