Components, systems and materials › Railway track components › Rail
Rail
What it is
The rail is the steel running surface of a railway track that carries and guides the train wheels and passes their loads to the sleepers.
Where it is used
Main lines, freight corridors, metro, high-speed, tram and crane tracks.
How it works
A rail acts as a continuous beam on elastic supports: each wheel load is spread over several sleepers. The hard head resists wear and contact stress, the web provides depth for bending stiffness, and the wide foot gives stability. Rails are welded into long lengths so there are few joints, and their longitudinal stress from temperature is controlled by laying them at a chosen neutral temperature.
Types
- Flat-bottom rails in standard sections chosen by axle load and speed
- head-hardened rails for sharp curves and heavy haul
- grooved rails for street trams
- check and guard rails at crossings and bridges
Materials
High-carbon rail steel with manganese, produced under strict cleanliness control; heat-treated head-hardened grades for wear resistance.
Section and grade are chosen from axle load, speed, annual tonnage and curvature. Long welded rails require adequate ballast resistance, sleeper spacing and fastenings to prevent buckling in summer and fracture in winter. Rail wear limits trigger replacement.
Installation and QA steps
- Unload and handle rails with proper lifting beams to avoid kinks.
- Join by flash-butt welding in depots or thermit welding on site.
- Destress the long welded rail at the specified temperature range.
- Grind to profile.
- Inspect welds and rails ultrasonically at set intervals.
- Rail and weld fractures in cold weather
- track buckling in hot weather
- head wear and side wear on curves
- rolling contact fatigue cracks such as head checks
Codes cited
- IRS T-12 (RDSO) (India): Indian Railway standard specification for flat-bottom rails.
- EN 13674 (series) (Europe): Railway rails.
- Indian Railways Permanent Way Manual (India): Standards and practice for track laying and maintenance.
Cited by number only. We do not reproduce code text, tables or figures.
Related
Why rail tracks have gaps
Steel grows in heat; gaps and modern welded rail handle it differently.
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