i couldn't read all the comments and ideas about duisburg problem but i suggest if possible, stop the game producing jobs from duisburg and to duisburg may reduce the traffic in and around it. yes, zero jobs.
i am a new player also. and i was not aware of the congestion until i arrive there with a job. and new players cause the problem. trolls will be left by theirselves in duisburg and managing the server will be much easier.