Characteristics and Improvement Trends of Rail Sections

Characteristics and Improvement Trends of Steel Rails

Steel rail is an important component of railway transportation, which transmits the power of locomotive to the wheel, and bears the huge weight of the train vehicle. Its quality and performance directly affect the reliability, comfort and speed of railway transportation.Therefore, it is necessary to further improve the section form, grading regulations and produced technology of the steel rail in order to ensure the safe, reliable and efficient operation of the railway.

Characteristics

Steel rail can be divided into ordinary narrow steel rail, ordinary wide steel rail and crane rail according to the purpose. Generally, the section size of ordinary narrow steel rail is 85kg/m, 60kg/m, 43kg/m and 38kg/m; the section size of ordinary wide steel rail is 15kg/m, 24kg/m and 30kg/m; the section size of the crane rail ranges from 30kg/m to 90kg/m.

The main component of the steel rail is the rail foot, which is composed of two sides and a web. The section size of the transverse section mainly includes the width of the rail head, the height of the railhead and the height of the railfoot. Usually, the types of steel rail section shapes are diverse, and can be divided into flat bottom rail, V-shaped rail, slide rail, groove rail, etc.

Improvement Trends

Under the trend of modern railway development, in order to improve the service life, the selection and production of the steel rail have changed a lot.

At present, most of the railway steel rails used are high-quality and high-performance quenched and tempered steel rails. Compared with common steel rails, the production of quenched and tempered steel rails requires the accumulation of carbon and the increase of its hardness.

In addition, with the continuous increase of railway speed and bearing capacity, the rail structure has also been significantly improved, such as the light rail.Moreover, due to the large number of engineering tunnels and bridges, it is necessary to strengthen the sliding resistance of the rail foot, so the rolling surface of the rail foot has been improved.In order to meet the traffic requirements of trains passing megacities in the future, the specific gravity of the steel rail has also been further decreased, which has reached a very low level.

Finally, the rail grooving technology has been used in the welding process of the steel railway. The head grooving is used to reduce the corrosion of the rail by adding lubricating oil or wax on the surface; the side groove is used to control the wear of the vertical flange, etc. These improvement measures have greatly improved the service life of the steel rail.

Conclusion

To sum up, in order to ensure the safe, reliable and efficient operation of railway transportation, the section form, grading regulations and produced technology of steel rails have been improved significantly. With the increasing speed and bearing capacity of railway transportation, the steel rails has gradually changed to high-quality and high-performance quenched and tempered steel with low specific gravity, which effectively ensure the long-term use of steel rails. What’s more, the grooving technology has been used to reduce rail wear and corrosion. All of these improvement measures guarantees the safe, reliable and efficient operation of railway transportation.

Steel rail section is composed of two web plates and two wing plates, which is a special I-beam cross section. Steel rail sections have the characteristics of compact structure, scientific force angle, good distribution and uniformity of stress, large bending strength and high rail wear resistance.

The shape, size and characteristics of steel rail sections have gone through a long period of development and improvement, from wide to narrow, from flat to round, from low specific strength to high specific strength. In the early days, the rail section was very wide, obviously larger than the width of the crosshead on the rail. Since the entering of the 20th century, with the improvement of steelmaking process, the specific strength of steel rail has been significantly improved, the rail width have became narrower, the rail size has been continuously improved and optimized.

At present, the international steel rail section generally adopts 900A69, 900A75 and other types. In addition to the conventional dimensions of the steel rail section, with the increasing demand for rail wear resistance and fatigue resistance, there have also been some new developments, such as the adoption of more complex box-shaped rail sections, reducing the inclination angle of the wing plate, increasing the rail foot diameter and reducing the rail head height.

These improvements are usually aimed at increasing the uniformity of the rail stress distribution, improving the resistance to fatigue damage, and reducing the crosshead-rail friction and wear. With these improvements, the safety and service life performance of the steel rail has also been improved.