Train Set :

Bachmann Trains Pacific Flyer Ready-to-Run HO Scale Train Set
http://www.amazon.com/Bachmann-Trains-Pacific-Flyer-Ready/dp/B001RG0LLE

Planning to buy 1 HO Scale train set , 1 steam locomotive, 1 diesel locomotive and extended tracks.

 

Good luck.
I couldn't understand. Are you going to purchase Bachmann model from the US or you are going to order it from India.
I believe you have plans to buy it from the US. The reason is, to my knowledge, Amazon does not ship to India.
Another thing is power controller and adapter to control the locomotive will be 110V, 60Hz rated.
Hence you need a good step down converter to use in India.
I have one purchased for 250 INR.
Also give a try for Ebay US.
You have tons of rail modelling products on the ebay.
I guess this is your first model. Hence keep in mind to purchase items for future expansion purpose.
In India rail modelling is at infancy and may take a while to establish itself with international brands like Bachmann, Lima, Rivarossi, Roco etc.