Kafi saare valuable replies ke baad yahi conclusion nikal rha h ki ECR m slack ke bahut saare reason h..

High Traffic density
Highly population area
Week infrastructure
Lack...
more...

of doubling tracks
Lack of Terminal Facility
Weakness of track soil

And most imp and simple reason is ECR Zone intension

IRIians call it SLACK.
Railways say it - Engineering Allowance + Traffic Allowance.

Railway Board has put a cap on the Engineering Allowance per 100 kms of section.

But,...
more...

left "Traffic Allowance" to be decided by the CPTM/zone, and that's why some of the zones / CPTMs misuse this. ECR is on top of that list.

For example - Train 02872 has 73 minutes of Traffic Allowance in last 36 kms of it's journey between DNWH and IPR.
Engineering allowance is kept just around 10 minutes.
So, basically the point raised by you can simply get resolved if the CPTM follows the guidelines for table tabling (which is shared in every IRTTC meet).

I just scrolled through the replies on this post and found members suggesting ways to decongest RJPB / DNR.
For everyone's kind attention - I daily see, trains like 02393 and 02309 getting placed at RJPB platform just 4 hours in advance. Last week, I got down at RJPB from Magadh 02871 at RJPB PF3 and found my connecting train 02393 already placed at PF2 (it was 17:00 around), and a PF vendor told me that it was placed around 16:00 along with 02309 at RJPB PF1, and their departure time is around 19:30. So, this way operations team @ DNR creates congestion. CONGESTION is just a man made creation at ECR.