U need to check the TT from the originating station to know why excess slack is given at the end of any intermediate station. This train was given TT from MTM upto GNT on par with daily running time. From GNT to Nandyal 257km was given 4hra 15 min with 60kmph the ghat section MPS is low and single line will take more time atleast 5.5 hrs then NDL to Yerraguntla 120km single with low MPS will take 2.5 hrs with avg of 50kmph and 20 mins for loco reversal against 10 mins given. So all these adjusted there is not much slack to the train in overall journey.

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in VSKP VJA section upto Eluru or reverse upto Anakapalle is given 4 hrs running with but total time is 5.5-6hrs with slack of 30-60 mins for a train that doesn't mean they can adjust slack and make it early as trains running at 130kmph yet take the same time as TT with 110kmph.

The sole purpose of Timetable is to follow the given schedule on daily basis for all trains even in intermediate stations and type of TT should be checked in IR and given realtime TT. I don't support the present TT of IR. Today time is money and IR cannot take travellers time for granted.