finally Got PG portal reply about Sadbhavana Express trains Inaugural Run date ,, according to that reply this 14014/14013 SLN-DLI Sadbhavana Express is Oldest train of its gang ,,, as thy didn't have any info about this trains Inaugural Run date
reply by PG PORTAL :-
Train no 4017/4018 was introduced w.e.f 06.08.97, train no 4007/08 and 4015/4016 was introduced w.e.f 03.07.94 . date of introduction of 4013/14 is not available.