@others :
As per IR circular on :-
.......CHARGING OF SR. CITIZEN TRAVELLING ON CONCESSION
"The issue regarding charging of senior citizens travelling on concession, who do not produce age proof during journey, has been examined. MINISTRY OF RAILWAYS HAVE DECIDED THAT IN SUCH CASES, ONLY THE DIFFERENCE OF CONCESSIONAL FARE PAID AND NON-CONCESSIONAL FARE PAYABLE SHALL BE CHARGED. PENALTY WILL NOT BE...
more... CHARGED IN SUCH CASES." ........
So authentic age proof is must.