Why are there crushed stones alongside rail tracks ?
- The crushed stones that are present alongside the railway tracks are collectively known as track ballast.
- The railway tracks are made up of steel and are supported by wooden ties (used previously) or concrete rectangular slabs which are known as sleepers.
- Railway tracks are normally subjected to heat expansion and contraction, high-speed movement of trains, vibrations etc. Tracks should withstand all these factors for a safer journey.
- In order to do this, crushed stones are placed between the sleepers (or wooden-tie) and also around the tracks.
- The crushed stones are capable of keeping the wooden sleepers in place and they will, in turn, hold the railway tracks firmly.
- The stones should not be smooth because they may slide over each other when the train is passing over it. So, stones with rough edges are used.
- Crushed stones also serve other purposes like – draining of water beneath and around the tracks, stopping the plant growth to a certain extent and more importantly, holding the tracks firmly even in the case of super heavy trains.