3 TO 4 Platforms are enough to make a terminal to start a train. the unused anna nagar can become a terminal for west bound train only based on sapce constraint. since shalimar has only 2 platforms but it acts as a terminal for kolkatta. pitline can be constructed at villivakkam and a byepass line connecting tiruvallur route will be enough. Annanagar is in main city and it has better access to cmbt Koyambedu.