You may have heard about the problems the German railways (DB) are currently facing with their new IC2 trains. The double deck coaches seem to sway too much (sideways, 'Wankung') in every service, reducing the comfort level of the trains severely. Bombardier is working on the issue.
The formations with TRAXX locomotives are now in service on IC line 56 Norddeich – Leipzig. The DB first want to stabilize the availability of the IC2 trains on this route before introducing it to other lines. This means that the IC2s will come later to the IC lines 35/50/55 as planned:
Line 55 Köln – Hannover – Dresden > second half of 2016
Line 35 Köln – Norddeich > March 2016
Line 50 Köln/Frankfurt/M. - Erfurt and beyond > March 2016