Sunday, January 13, 2008

Is there any significance in using gravel on railway tracks?

Yes. Gravel used on railway tracks is known as ballast. It is used to dissipate the vibration produced by trains traveling at high speeds. In effect, the gravel layer acts as a cushion and damps the vibrations so that they do not travel long distances. If the rails are laid on a solid base, these vibrations can travel long distances and lead to cracks on the base as well as on nearby buildings.

The ballast provides a foundation for the sleepers, distributes the pressure on to the formation and helps in diverting the rain water. In a typical ballast, voids constitute 20 to 30 percent of the volume.