Basalt or granite ballast, coarse gravel or crushed stone used for laying roadbeds for highways or railways, primarily for railway subgrade. It is a common trackbed structure used in the railway transportation system as ballast to support railway sleepers. Before laying the tracks, the subgrade is first covered with ballast, which is then compacted, followed by the placement of sleepers and tracks. Using basalt or granite ballast facilitates easy drainage and easy adjustment of track positions. Additionally, as the ballast distributes the weight of trains and tracks over the subgrade, it reduces vibrations and noise caused by trains passing by, enhancing passenger comfort.

And both basalt or granite ballast can simultaneously dissipate the vibrations and high heat generated by trains passing over, maintain the gauge of the rails unchanged, prevent derailment accidents, and reduce noise. Moreover, the gaps between the stones can quickly drain rainwater. Additionally, the ballast made of basalt or granite has strong permeability, which can prevent weeds from growing on the tracks.