The problem with ECR is having too many trains without having sufficient infrastructure. For eg, a train bound for DDU from MKA needs to cross Patna area but, PNBE is too much saturated and hence accounts for delays. To counter these delays DNR division gave slacks to the trains. Similarly, the trains terminating at PNBE/RJPB were delayed due to platform constraints at these stations. RJPB has only 2 platforms for terminating/originating trains. 2 platforms are for passing trains. This is just for passenger trains. Now, think about goods traffic. May be after JAJ - PNBE - DDU tripling, we can expect these slacks to come down a bit. Same goes with MFP, BJU, GAYA, etc.