Basalt or granite ballast, coarse gravel or crushed stone used for laying the subgrade of highways or railroads, primarily for railway subgrade. It is commonly used as ballast to support railway sleepers in the railway transportation system. Before laying the tracks, engineers first lay a layer of ballast on the subgrade, compact it, and then place the sleepers and tracks. The use of basalt or granite ballast facilitates drainage and easy adjustment of track position. Additionally, as the ballast distributes the weight of trains and tracks over the subgrade, it reduces vibrations and noise during train passage, enhancing passenger comfort.

And the basalt or granite ballast can simultaneously dissipate the vibration and high heat generated by trains passing by, maintain the gauge of the rails unchanged, prevent derailments, reduce noise, and quickly drain rainwater through the gaps between the stones. Moreover, the permeability of the basalt or granite ballast is strong, which can prevent weeds from growing on the tracks.