Nice Idea. But a train should have an origin and destination.
Origin and destination cannot be same.
So, it should be NZM-NGP-BZA-TPTY.
TPTY-KRNT-SC-NGP-NZM
NZM- NGP SC KRNT TPTY
TPTY...
more... BZA NGP NZM.
This way, they can run in all possible routes. Since, 2 routes are existing already, other 2 can be implemented.
Just the KA SK runs in 2 routes with RSA.
Pradyu !!