Why do railway tracks have crushed stones alongside them? - Alpha Rail
Track ballast is the name for the crushed stones next to railway tracks. They are used by Railway Track Designers for numerous reasons
Hasnain says:
“Without the ballast in place, railway lines would simply not be able to cope with the stress from the weight of the trains passing over them, not to mention the impacts of expansion and contraction.
So, the next time you are near a railway line and you see the loose stones all around, you will now hopefully have a greater respect for the role they play in getting you safely to your destination.”