There are following possibilities:
1) Either Kaveri Express would be moved to Egmore with change in Number to 6121/22.
2) Pearl City would start from Central and then via Egmore.(Most special trains to southern districts do that).
3) As I mentioned earlier, after maintenance at BBQ, the rakes would be sent to MS.
4)...
more... Kaveri would be transferred back to Mysore Division. Instance is the case of MAS-HYB Express (From SR to SCR to SR, all within 1 year).