1)Already 3 lines and 4th is proposed for SFG-ALD
2)All PFs at ALD are capable of holding 24 coaches trains from like 25 years before.
3)Vibhuti runs from ALY and has nothing to do with the congestion of NCR.
4) Cannot terminate Sangam Express at PYG, there's no connection and reversal has to be done PRG.
5)...
more... Yes ALD-MUV will be doubled by 2021, and few trains may be diverted via this route, however it will make BSB extremely congested and trains will troll around BSB-DDU and will become a nightmare for passengers.(Instead third line between ALD-DDU+DFC will serve the purpose)
6) Capacity and platform development is already under construction for ACOI.
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Conclusion: You have little knowledge about the affairs of ALD, please do a thorough research to scrutinize the facts.