I have purchased an online ticket to go from Cologne to Dusseldorf; the ticket is from Brussels to Dusseldorf with changeover at Cologne.
I heard that in German cities train tickets need to be validated in a machine. Will I be required to do this for an online ticket? If yes, where can I validate?
I completed my journey and it was wonderful, ICE trains are awesome! Just a printout was sufficient. They didn't ask for ID, but may have asked, so I had my passport with me. Thanks all for the help.