The girls — ages 15 and 14 — were arrested at the Joyce SkyTrain station in Vancouver on Monday night.
The 15-year-old is in custody and faces 11 charges including two counts of assault with a weapon, two counts of posession of a weapon dangerous to the public peace, assault causing bodily harm, uttering threats to cause death or bodily harm, and five counts of breaching conditions that already existed under the Youth Criminal Justice Act.
On Wednesday afternoon, a spokeswoman for the transit police said a warrant was being issued for the 14-year-old's arrest. She has been charged with one count of assault causing bodily harm.
The teen had been released into the care of her grandmother, but police said she is due in court tomorrow for an unrelated matter. Officers plan to take her into custody then.
Three people were wounded during attacks which started late Monday night at the Gateway SkyTrain station in Surrey.
One of the girls allegedly slashed a woman on the arm with a knife before the pair boarded the SkyTrain in Surrey. The girls then allegedly confronted another woman and followed her off the train at New Westminster's Columbia Station. The woman told police she was chased by the girls and punched in the face.
At Joyce Station, a man was attacked.
The girls were arrested shortly afterwards by transit police.