Comment 4 for bug 535882

Also reported at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=671719

I've attached a savegame (see marble mines) from bzr6567 showing a deadlock as mentioned in #2 "the problem is caused by a carrier who wants to deliver something and he can't cause it's full and when exactly THAT carrier is the only possible solution to solve the deadlock."