for example, madurai to chennai
madurai can fill a full train to chennai
So, a train madurai-chennai should get filled whether it runs via mdu-dg-tpj-cl-MS or MDU-dg-krr-nmkl-sa-mas or mdu-dg-tpj-ml-ms if it runs in around 9hours(the normal travel time mdu-ms is 8h/8.5h)