understand that seniors over 65 , the train tickets within Belgium , there is a special lower price , is it for anyone in the world age over 65 or must the travellers be holding an EU passport ?
It is for anyone. It is the honor system; you show the conductor checking your ticket your ID if they don't believe you are over 65
I’ve never had a conductor/train manager ask me for ID with the senior rate although I’m always prepared to show my passport. The gentleman who checked my ticket on Thursday as I headed to Ghent was more worried that I would be upset I had gotten on the “scenic” route which took an hour vs the quick route which took 30 minutes. It didn’t bother me and yes I enjoyed the scenery!