the reason for following irctc/indiarail.gov.in is that the timings printed on ticket is always as per irctc timings and when there is a contrast in timings of ntes and irctc the timings on booked ticket will be UA.
after the new official portal of indian railways if someone clicks to see train schedule they will redirect you to NTES only but it appears complete incorporation of timings into irctc is yet to be done which results in "unavailable" arr dep timings on booked ticket.
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Above every thing the fact remains correct that unlike earlier days the correct and latest schedule of trains are on ntes only as far as public is concerned.