Circar express: Scheduled time for Korukkupet is 5:48 am and Egmore is 6:05 am
Charminar: Present Scheduled time for Korukkupet is 8:09am and Central is 8:15am
So the net difference would be 5...
more... min more.
During platform unavailability or Signal clearance delay, train gets halted somewhere before reaching Central and after Basin bridge for central. If it is egmore, they may stop at Beach / Park. This will enable people to get down there itself and board a local MMTS to reach their home a bit early.
Hence i feel it is a good move to change terminal from Central to Tambaram and the delay wouldnt be more than 5 to 10 min