The Alexandria City Council last night unanimously approved the use of portable classrooms for the Cora Kelly Magnet School to ease crowding there.

Three trailers holding six classrooms will be parked outside the school at 3600 Commonwealth Ave. beginning in September.

The vote came after council members Lionel Hope and Redella (Del) Pepper, both Democrats, criticized Superintendent Robert W. Peebles for not addressing the crowding problems sooner. They said Peebles also should have given the school's principal an assistant.

The principal, Mercedes Morrison, recently took an indefinite leave of absence, saying the superintendent and School Board failed to support her.

Cora Kelly, the only magnet school in Alexandria, has been faced with a variety of problems, including insufficient staff members, that resulted from crowding. Cora Kelly's enrollment peaked at 636 students this year.

The School Board voted on June 25 to reduce the number of students and to increase the amount of classroom space by leasing the trailers.

The board's redistricting plan calls for moving about 175 children from Cora Kelly to other elementary schools.

The trailers cost about $17,900 each to rent, install and equip for one year. They will be used for special classes, such as English as a second language and remedial reading.

Cora Kelly was made a magnet school in 1984 to attract white students to the predominantly minority neighborhood of Lynhaven by offering special programs in computers and science.

Peebles said 500 is the maximum number of students a magnet school should accommodate.