India is a vast country with varied landscapes and topography and the soil varies from region to region place to place.
Painting the entire landmass of India with one brush and characterizing its soil type as a monolithic is not really smart. The soil varies from place to place.
This is the Qinghai railway. Connects Beijing with Lhasa.
it’s currently the highest railway in the world.
550 kms of the Qinghai railway is built on Permafrost.
Go do research on constructing anything on permafrost.
While not a high speed railway, the challenges of constructing a railway on permafrost is way more challenging.
Both Russia and China have railways built on permafrost and the construction is way more challenging as you have to reinforce the ground underneath before you can build on it and make sure the hardened soil doesn’t melt away.
So as you can see, even if I were to take your assumption of a monolithic soil type in entire India, engineering can overcome it and I highly doubt your premise is correct.
Manhattan in NYC has glacial till soil as top layer and so does many other boroughs.
This is the Manhattan skyline
How did they construct the skyscrapers?
By going deep into the ground till they hit bedrock where they can anchor the pillars that support the structure.