The right question should be, why was Rajendra Nagar Terminal(RJPB) developed inspite of being very near to Patna Jn?
The answer is, to decongest Patna Jn. A train originating/terminating at Patna Jn would block a platform for approx 30 min either way( i.e.. 60 min in a day if it's a daily service). If the same train originate/terminate at a Remote Terminal like RJPB, it can depart PNBE within 10 min( thus, saving precious 20/40 min).
please wait...Translate to HindiSahi sawal hona chahiye, Rajendra Nagar Terminal (RJPB) Patna Jn ke bahut nazdeek hone ke bawajood kyun banaya gaya?
Jawab hai, Patna Jn ki bheed ko kam karne ke liye. Ek train jo Patna Jn se shuru/hone wali hoti hai, 30 minute tak kisi platform ko rok deti hai (din mein 60 minute agar yeh train roz chalti hai). Agar wahi train Remote Terminal jaise RJPB se shuru/hone karti hai, toh PNBE se sirf 10 minute mein nikal sakti hai (is tarah, 20/40 minute bachate hue).