Feeling bored in the Train - talk to a RailFan. You'll WISH the train gets late.

it will depend Mr Milind. Even if an extra SL is attached, the persons in RAC will get the confirmed berths in the extra bogey. Exactly how they will deal with the other W/L passengers is not certain. The problem is that presently platforms are fixed for 24 coach composition/25 coaches at certain stations. So it will depend entirely on the DRM/Train controller who will decide.
But my own feeling is that during the season, people book multiple tickets for the same day train/s and cancel at the last minute i.e. 24...
more...

hours before departure time, because they will incur only RS 20 as a charge, or Rs 60 as charge for cancellation for SL/AC classes. They will choose the train that suits them the best, and cancel the REST.
Therefore I said that you have a chance to come into RAC at least. If an extra compartment is added, then you will, depending upon your RAC status, and how many compartments are added, you might get either RAC or confirmed berth. Beyond this I cannot say anything with certainty. Certainly Good luck and good wishes.