I suppose you are landing in Dusseldorf from the US. Before you leave you can get a Eurorail pass online, but you may/may not buy a ticket direct from German rail ( I could be wrong here). You can get a ticket at the railstation in Dusseldorf when you get there. The Germain trains are great. One reason I mention that you may be able to order rail tickets I tried to find a method to get from St. Petersburg Russia to Findland when I was there and I think I could have reserved a ticket online if I had wanted to take a 14 hour train ride. If you are going soon make sure you take a coat with you to Dusseldorf it is starting to cool down this time of year and can get pretty cold.
Köln Hauptbahnhof to Paris Gare du Nord, 3 hours 22 minutes on one of the four direct trains per day (Thalys high speed train).
4 hours if you have to change in Brussels.
about 4 hours probaly 5
According to raileurope.com a train from Paris to Madrid takes approximately 13 hours.
About 4 Hours.
clear 3 hours
The quickest train from Brussels to Paris usually takes not very long at all. The quickest train from Brussels to Paris usually takes about one hour and fifteen minutes.
7 to 8 hours.
About 3 hours
1 hour
This depends on if you take a bullet train or regular train. Regular train is actually about 13 hours. 5 hours
You take the train from Paris-Saint-Lazare
It depends how much money you have .
About 2.5 hours