Could you please post which trains you would like to take? Then people can advise where to book reservations for them.

Hi I don't have any preference on trains.

@Aashiq Wilfred 
Luxembourg - Koblenz - Zürich = no reservation needed but possible for 4€via bahn.de :)

Luxembourg - Metz - Strasbourg - Basel - Zürich (between Lxembourg and Basel just with TER trains even no reservation needed)

Luxembourg - Trier - Saarbrücken - Mannheim - Zürich reservation not needed but possible via bahn.de :)

I prefer the Route via Koblenz with the one daily Eurocity to Zürich nice trip along the Mosel and the Rhine Valley :)

till Koblenz i recommend to sit on the right side and from Koblenz on the left side  to get the stunning view

@seewulf Thanks a lot for the detailed response.:)  But I am not able to find any trains for Dec 24. Will the schedule be updated only later for these dates? Would you know when? 

Luxembourg railways have not yet sent their new timetable to the European Timetable Centre. That should however not take too long anymore.

@Aashiq Wilfred 
You could plan with the actual timetable as no bigger changes are planned for this December :) 

Luxembourg - Koblenz goes every hour a train maybe have a short stop in Trier or Cochem and catch then in Koblenz the direct Eurocity to Zürich :)