Caution: This is not my imaginary list to you but real one that is wanted for the people who are involved in traveling to these places.
1) Coimbatore - Lucknow.
2) Coimbatore - Patna.
3)...
more... Coimbatore - Howrah.
4) Coimbatore - Any prominent cities of north east.
5) Coimbatore - Bilaspur.
6) Coimbatore - Any other cities of prominence in UP, bihar, jharkhand.
7) Coimbatore - Jabalpur if needed could be extended to Prayagraj.
Coimbatore has dedicated train only to Rajkot, Mumbai, Delhi, Hisar, etc in north which I feel is grossly inadequate for a city of this status.
Any other routes or suggestions invited.