Y'are right that the new routes and doublings of SECR/CG are meant for increasing freight traffic, so the rate of return on investment on SECR projects had been highest till 2015, which may come down in future if investment in Guage conversion increase.
DGG-Khairagarh-Kawardha-BSP route was surveyed twice in eighties & in late nineties and declared financially unviable. Today probably coal/bauxite transportation is expected from this line