thank you for comprehending the Question, and analysing the answers of other contributors in right perspective.
As you have rightly given example of Airlines, it works with air travel. But for rail travel, it is very tedious, time consuming, costly. But if a traveller, Single Traveller and that too, non Indian or for that Indian wishing to visit India with shorted time and low budget, will be happy to know the shortest routes and plan the journey accordingly.
So,...
more... still some enterprising techie comes up with the resources to supplement the mapping of rout, it will be good, in the interest of Rail Yaatris...