The devastated daughter of the Atlanta train passenger viciously slaughtered by an alleged homeless maniac in a random attack ripped local officials Monday for opening the transit system to free riders — and then failing to properly police its stations. Margaret Swan, a 66-year-old great-grandmother, had her throat slashed and then was stabbed 18 to 20 times on the Metropolitan Atlanta Rapid Transit Authority by the knife-wielding madman in an unprovoked attack Saturday morning, cops said.