Sir,this is already implemented.Check in ARP Calculator.
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ARP (Advanced Reservation Period) Calculator
Reservations Open Today @ 8am for:
Trains with ARP 10 Dep on: Fri Apr 3, 2015
Trains...
more... with ARP 15 Dep on: Wed Apr 8, 2015
Trains with ARP 30 Dep on: Thu Apr 23, 2015
Trains with ARP 60 Dep on: Sat May 23, 2015