page_title: Rail profile
section_title: Barlow rail
hierarchical_section_title: Rail profile / Types / Barlow rail
caption_attribution_description: English: Cross section of Barlow Rail as used by Sydney Railway Company
context_page_description: The rail profile is the cross sectional shape of a railway rail, perpendicular to its length.
  Early rails were made of wood, cast iron or wrought iron. All modern rails are hot rolled steel with a cross section approximate to an I-beam, but asymmetric about a horizontal axis. The head is profiled to resist wear and to give a good ride, and the foot profiled to suit the fixing system.
  Unlike some other uses of iron and steel, railway rails are subject to very high stresses and are made of very high quality steel. It took many decades to improve the quality of the materials, including the change from iron to steel. Minor flaws in the steel that may pose no problems in other applications can lead to broken rails and dangerous derailments when used on railway tracks.
  By and large, the heavier the rails and the rest of the trackwork, the heavier and faster the trains these tracks can carry.
  Rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by steelworks at one time, so a railway must choose the nearest suitable size.
context_section_description: Barlow rail was invented by William Henry Barlow in 1849. It was designed to be laid straight onto the ballast, but the lack of sleepers (ties) meant that it was difficult to keep it in gauge.
caption: Cross section of Barlow rail as used by Sydney Railway Company
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