KGI can't decongest SBC to a greater extent, as most of its long distance trains travel towards the opposite direction and hence, every train should enter and exit SBC.. that's an extra burden.. also, there are very few trains which can start at KGI towards MYS. That's why they opted YPR, KJM and BAND. even now, KJM is not a good option for a terminal.. trains now start from BAND and future from Baiyappanahalli. Correct me if I'm wrong somewhere, but this is my analysis..