PITTSBURGH — Northbound traffic is moving again on Interstate 279 after a fire involving a tractor-trailer carrying mail.

Fire officials say the truck caught fire after apparently blowing a tire and striking a guard rail early Monday in Ross Township, Allegheny County.

The blaze closed northbound lanes of Interstate 279 for several hours as crews fought the diesel fuel fire.

Officials say much of the mail on the truck was damaged in the blaze. The driver was able to get out of the truck before the fire began.