Rather i will say it uses 7 of 8 routes as we can add Basin Bridge chennai central : Mumbai Chennai route
So the final list
sawaimadhopur nagda : Delhi Mummbai Western line route
Bhopal Itarsi : New delhi Bombay central route
Itarsi...
more... : Howrah Mumbai main(via Allahabad) line route
Bhopal chennai : Delhi chennai route
Nagpur Sevagram : Howrah Mumbai SE Route
Vijaywada chennai : Howrah Chennai route
Basin Bridge chennai central : Mumbai Chennai route
Only metro connecting route it doesnot use is Howrah Delhi route