Three techniques for rail straightening

Introduction

Steel rail straightening is an important process in railway construction. It is a method used to cut and shape steel rails to the correct profile and correct bent sections. Various straightening techniques are available from manual to automated, depending on the size, shape and complexity of the required straightening work. This essay will provide a brief overview of three steel rail straightening techniques: manual, hydraulic, and heat-induction.

Manual Straightening

Manual straightening requires the use of a wedge and a hammer to straighten the steel rail along the horizontal and vertical directions. The process starts by chiseling a saw-toothed edge into the rail. The severity of the alteration should be determined in accordance with the amount of angularity existing in the rail. Using this process, the rail is then folded/bent along the saw-toothed edge to a designated shape. After the rail has been bent to the required shape, a hammer is used to remove any residual angularity and straighten the rail. This process is not suitable for curved sections of the rail, due to the difficulty in determining the exact angularity of the curved section.

Hydraulic Straightening

Hydraulic straightening is the process of utilizing high-pressure to straighten steel rails. The process begins by pre-heating the steel rails with a specific temperature as suited to the desired straightening shape. Then force is applied over predetermined areas in an up-and-down motion. After the application of the force, the rails are cooled with water and are then inspected for any residual angularity. This method of straightening is ideal for curved rail sections, as the pressure can be adjusted to ensure the correct shape of the curve.

Heat Induction Straightening

Heat induction straightening uses electrical energy to generate heat in the steel rail with the help of a coreless induction furnace. The temperature for straightening is determined by the type of steel being used. After the rail has been heated to the desired temperature, a hydraulic jack is applied to the rail in an up-and-down motion, thereby allowing the heated parts of the rail to cool, while simultaneously straightening them in the process. This method is also suitable for curved rail sections, as adjustments can be made to the pressure applied and the temperature at which the rail is heated.

Conclusion

Steel rail straightening is an important process which helps to ensure that the steel rails are the correct shape, size and complexity for the tracks they will be used on. Various techniques exist to achieve a successful straightening effect, including manual, hydraulic and heat induction methods. By understanding the advantages and disadvantages of each technique, the most suitable method for individual straightening tasks can be chosen.

In order to guarantee the straightness of railway tracks and make railway running safely, it is necessary to adopt proper processes for steel rail straightening.

At present, three main process are used for steel rail straightening, including hot straightening process, cold straightening process and straightening by hammering out.

In hot straightening process, the steel is heated to a certain temperature and then straightened by a die. This process ensures the Specification requirements of the steel rail and its straightness, with fewer cracks on the surface and improved surface quality.

In cold straightening process, the cold straightening press applies stress to the steel rail and then turns around the steel rail. It has the advantage of fast speed, which can be completed at one time, and can effectively reduce internal stress.

Hammering out straightening is a process of directly pressing or hammering the steel rail on the side. This method not only improves the straightness of the steel rail, but also eliminates the fatigue fracture of the material in use.

In summary, these three process are applied to steel rail straightening. Hot straightening process provides higher accuracy of straightness, cold straightening process has the advantage of fast speed, and hammering out straightening reduces the material fatigue fracture in use. Therefore, selecting the proper process to straighten the steel rail is the key to the success of railway moving safely.