the was a shop in Madurai. It was victorry hobbies.
http://www.rcindia.org/kites-trains-free-flight-and-all-others/model-trains-largest-collection-ever-found-in-india/There is a address given.
I see you are in Delhi.
There is a shop Decibel scale models up in pitampura.
It is better importing from US and Europe as they are cheaper.
you may get a SD40-2 here for 12000
while they same may cost you 4000 from outside.
There is another shop; trainaidsa.in
very helpful person out there.
I have a DC TGV layout with me.
Gimme a PM if you need any help regarding the models.
Regards