Then in that case, a simpler solution does exist....
1. For MGS, IR can construct a flyover for freights (just like KYN in CR Mumbai to crossover to NE line without interfering SE line) which will join the main line a couple of kms post MGS ..
2. For ALD there is a need for separate pair of lines by...
more... shifting of ALD yard to few kms off ALD and using the present one by remodelling it to use as a terminal for few trains leaving the existing ones for passing trains...