for (TrackPlaylistMap::iterator x = trpl_map.begin(); x != trpl_map.end(); ++x) {
boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (_session->route_by_id (x->first));
for (TrackPlaylistMap::iterator x = trpl_map.begin(); x != trpl_map.end(); ++x) {
boost::shared_ptr<Track> tr = boost::dynamic_pointer_cast<Track> (_session->route_by_id (x->first));