Four people were arraigned Tuesday in connection with the alleged brawl on a subway car on March 9 that left three people requiring medical treatment.
Michael Davis, of Quincy, and Patrick Joyce, of Dorchester, were charged with assault and battery and assault with a dangerous weapon.
Kevin McCarthy and Kristine Mullen, both of South Boston, were also charged with assault and battery and assault with a dangerous weapon.
Authorities said a fifth person is expected to be arraigned Friday.
One young male victim was taken to a hospital for treatment and two teenage girls from Lincoln were treated at the scene after the fight inside a Red Line train.
A passenger shot video of the fight, which MBTA police made public.