Method and apparatus for tracking thread stacks during a trace of a computer program. The automatic update to playlists can occur when additional media content is added to or removed from the media system. The operator can suitably configure an appropriate Mobility Management Entity with information using a network Operations and Maintenance Support System. This adaptation produces a position correction signal. A number of rake wheels are mounted on each of the rake booms on the side of the boom nearest to the tow beam, wherein the rake wheels are adapted to move vertically with respect to the rake boom using a compression spring mechanism.