If you will kindly look at the site www.indianrail.gov.in and the running status therein of such trains, you will observe that departure/arrival times are being shown as say "7 hr 30 min late". I believe anytime IR may start operating the trains as per original schedule, so they are doing so. Another thing comes to my mind that for computerised reservation system, this is convenient. Only thing, one has to be careful while making reservation: example - if someone wants to travel by Howrah-Mumbai Mail which as per present schedule will depart from Howrah by 5.30am of 06/11/2011, he has to book for the train of 05/11/2011 (departure time as per original schedule by say 8pm of 05/11/2011).