Railway Steel
Railway steel is a type of steel specifically designed to be used in the construction of railway lines and systems. Traditionally, railway steel was made from a combination of several elements - iron and carbon, with other materials such as chromium and nickel also used to provide additional desired properties. The addition of carbon to the mixture is what makes railway steel distinct from other types of steel and stronger than standard iron.
The first use of steel in railway lines appears to be the Gauge 1 of the Stockton and Darlington Railway. It was opened in 1825 and a further seven lines using this steel were subsequently built in the United Kingdom. A further example of early steel railway lines is the Rocket, which was built in 1829, this time incorporating wrought iron hoops with a core of cast iron.
In modern times, railway steel is generally produced via the Bessemer or the open-hearth process. In the Bessemer process molten pig iron is converted, via a blast of air, into steel. In the open-hearth process exterior layers of pig iron are carburized at high temperature, before the interior layers are air-converted. These processes allow the creation of properties not achievable with other materials, such as strength and durability.
The majority of railway steel today is low-carbon steel, commonly known as mild steel, which is used in the production of rails, sleepers and bolts. For high-speed lines, special alloys are used to increase strength, as more dynamic forces are at work upon the railway line. High-speed railways have also recently started to incorporate composite materials such as reinforced concrete and high-tensile plastics as a means of achieving superior strength and superior resistance to oxidation.
The properties of railway steel can be further tailored to meet the specific requirements of any given rail line. For example, in order to reduce noise caused by train vibration, the steel used can be altered to reduce the amount of vibration that is transmitted from the rail to the sleeper. Alternatively, for under-bridge supports, the steel can be enhanced to achieve higher load-bearing capacity.
Railway steel is selected to meet different levels of demand, from heavily loaded intercity routes to simple single track or light railway lines. The essential properties of the steel designed for railways remain the same, namely strength, ability to cope with dynamic forces and corrosion resistance.
Overall, the use of railway steel allows for the construction of safer and more efficient rail transportation. Not only is it easier to install and maintain, but the properties of railway steel also extend its useful life, leading to increased reliability and cost effectiveness. Railway steel is therefore without doubt one of the most important materials in the development of railway infrastructure.
