NDLS-HWH had been the no.1 trunk line of India. It carries high volumes of passengers (esp NDLS-MGS) as well as heavy freight (esp MGS-HWH). IR developed it for high speed.
This route has witnessed introduction of a large number of new trains as it serves heavily populated areas and most of the RMs in last 2 decades hailed from the states served by this route.
Most of the trains say from Delhi to Orissa (BBS) run through this fast route rather than slower and partly single line alternate route via Bina-Katni-BSP-SBP. In...
more... fact IR should study which route they want to develop for travel between particular end destinations and develop accordingly.
Although, many patches of third line has been commissioned on this line, but real respite shall come when the DFC is commissioned and the SF trains shall run with avg speed of 75kmph and the Rajdhanis at almost 100kmph.