Boulder or granite ballast, coarse gravel or crushed stone used for laying roadbeds for highways or railways, primarily for railway subgrades. It is commonly used in the railway transportation system as ballast to support railway sleepers and is a common track bed structure. The project involves laying a layer of ballast on the subgrade before the track is laid, then compacting it, and finally placing the sleepers and tracks. The use of boulder or granite ballast facilitates easy drainage and easy adjustment of track position. Additionally, as ballast distributes the weight of trains and tracks over the subgrade, it reduces vibrations and noise generated by trains, enhancing passenger comfort.

And both basalt or granite ballast can dissipate the vibrations and high heat generated by trains passing, 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.