no guarantee for 8 a.m., its better u check before that also, just hapened with me, i was waiting for opening of 22476 CBE-BKN AC exp, it shows booking opened tomorrow, but just for checking i opened at around 7 a.m. in morning on net and booking was already started, i was lucky that i got all tickets b'coz, at 9a.m. only all seats become full, so don't take chance