Ab iss jagah pe Flyover nahi hai like Varanasi has from Mughalsarai or at different places also ek time pe ek train hi nikal sakti hai.
In addition to that don't forget the traffic from Rambagh and Prayag Junction at Allahabad Junction like (Shiv Ganga, Danapur Secunderabad, Gorakhpur Mumbai trains etc.), now last Platforms like 6, 7, 8, 9 & 10 have only limited number of dedicated access lines, so trains do take time