set<unsigned> used_addrs;
const set<Track *> &tracks = objects.get<Track>();
for(set<Track *>::const_iterator i=tracks.begin(); i!=tracks.end(); ++i)
set<unsigned> used_addrs;
const set<Track *> &tracks = objects.get<Track>();
for(set<Track *>::const_iterator i=tracks.begin(); i!=tracks.end(); ++i)