I post my inability to understand your post reply.
What do you intend to convey at all -- luxury of going to the train .... one needs to get used to.... ?
In the current post, it is very simple - either to book ticket from Dadar or CST to Chennai and both fall under the same quota and hence same availability of seats at either of the stations (CST or Dadar). And One would prefer booking
from...
more... CST without any hesitation by paying little extra Rs. 5-10 in fare.
And more importantly, Why should one need to get used to boarding at Dadar (intermediate station) when there is better option available (now known to the blogger) for ticket booking in future from CST ?
Thanks for all and good wishes.