I have a German 2nd Class Rail pass for 8 days booked for a trip next month. A meeting I thought would be in Aachen, Germany has been moved to Liege, Belgium. My trips will originate from the Frankfurt Airport. May I purchase a supplemental ticket to include the portion of the trip from the German border to Liege on the ICE? I have done this before going to Strasbourg - but that was a leisure trip and not on the ICE. Thanks.
According to the German Rail (Bahn) website, ICEs (14, 16, usw) from FRA to Aachen go on to Liege. You can buy a 2nd cl ticket from Aachen to Liege online from the Bahn for the same ICE for €17,50. You could also get off the ICE in Aachen, wait a few minutes, and take a regional train to Liege for €12,40. There is also such a thing as a German Rail Pass Extension, but I think it would cost you more that way than just buying p-p tickets.