India, Oct. 12 -- If you have ever looked out of a train window, you may have noticed a thick layer of small stones spread beneath and around the railway tracks. They might look like ordinary gravel, but these stones serve an important engineering purpose. From keeping the tracks stable to helping rainwater drain away, they play a crucial role in railway safety. So, why do railway tracks need these stones, and what would happen if they were not there? Let's find out. (Also read: Everyday explained: Why do websites ask you to accept or reject cookies? )

The stones placed beneath and around railway tracks are known as track ballast. They are generally made from crushed, hard rocks that form a supporting bed beneath the railway sleepers - t...