ballast

railway

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Last updated

June 18, 2026

Quick Summary

Ballast in the context of railways refers to the foundation layer on which the track is laid. It typically consists of crushed rock, slag, or volcanic ash. This material is tightly compacted around the sleepers (crossties) to ensure the track remains precisely leveled and aligned. Efficient drainage of the ballast is crucial to prevent instability, and its depth varies depending on the traffic load, being greater for high-speed passenger trains. In some cases, like tunnels or areas with drainage issues, ballast and sleepers are replaced by continuous reinforced concrete support, known as slab track.1

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railroad
Location and construction
…completed roadbed, its foundation is ballast, usually of crushed rock, slag, or volcanic ash. The sleepers, or crossties, to which the rails are fastened, are embedded in the ballast. This is tightly compacted or tamped around the sleepers to keep the track precisely leveled and aligned. Efficient drainage of the…
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…completed roadbed, its foundation is ballast, usually of crushed rock, slag, or volcanic ash. The sleepers, or crossties, to which the rails are fastened, are embedded in the ballast. This is tightly compacted or tamped around the sleepers to keep the track precisely leveled and aligned. Efficient drainage of the…
Read More