MBTA Transit Police have arrested a Boston man for an April incident on the Green Line.
Fifty-year-old Ronald Foster of Boston is charged with open and gross lewdness.
A female passenger told police that a man exposed himself and masturbated on the train at Haymarket on April 11.
MBTA released photos of the suspect on April 28. Foster was arrested Sunday.
He is expected to be arraigned Monday in Boston Municipal Court.
