law: 24. Exhibition and surrender of pass and ticket.
  Every passenger shall, on demand by any metro railway official authorised in this behalf, present his pass or ticket to such metro railway official for examination at the beginning, or during or at the end of the journey and surrender such ticket,
  (a) at the end of journey if the ticket is for a single journey, or
  (b) if such ticket is issued for a particular amount, on the exhaustion of the amount for which the ticket was issued.