Rail Bolts Maintenance

Sep 22, 2017
rail bolt faq
Rail bolt,also called track bolt, it is a kind of fasteners to fix the steel rails to the sleepers. In general, the rail bolt has two parts, the head and screws. Track bolt and nuts are two closed parts. Together with the nuts, the rail bolt can fasten the rails at a joint. The rail bolt and some others fasteners like rail clamp, rail spike, rail clips and the like constitute the rail fastening system. As a rail fastener, it plays a big role in guiding the train. Besides, all the fastening system bears the enormous pressure of trains and their loads. So the each fastener should have enough high strength and stability to ensure the train runs safely and steady even if the train at the highest speeds.

Types of Rail Bolt

  • By the force, there are the common type and the reamed-hole type. The rail bolt needs to suit the reamed hole that needs to custom the dimension of rail bolt. If you are looking for the track bolt manufacturer, please contact the AGICO RAIL.
  • By the shape of the head, there is hexagon bolt, cheese bolt, and coach bolt, etc.
  • Besides the common rail bolt, there are some special rail bolts. Such as the T-bolt, the shape is special. When you use it, you should cut the head and the bottom. The fish bolt is used for rail joints, and the surface material has many types like plain, oxide black, zinc, and HDG. The fish bolt is used together with rail nuts and spring washers.

Questions of the Rail Bolt

Of course, rail bolt will have some problems after a long-time work. When we use the rail bolts, there are some questions during the process of using. Now, we would like to introduce some problems and the causes.

Rail bolt looseness

When the workers examine and repair the rail fastening system, they found that the rail bolt looseness and the bolt hole slipped and others problems.
Firstly, compared with the new rail bolt, the rail bolt had a slight rotation and the torque value has reduced after a period of use.

Secondly, when at the same torque value, the mileage increased and the number of slightly rotating bolts increased.

What causes the rail bolt looseness? There are two reasons:

  • The quality of the rail bolt. Whatever the model, material, and the surface coating, that all can influence the service life. 
  • Implementation. Please use the torque wrench to fasten the rail bolt with 25N.m and guarantee the wrench rotates more than 60 degrees. If not reach these requirements, the implementation is not up to the standard.
If the rail bolt is loose, the safety of the train cannot be guaranteed. So tighten the rail bolts is a necessary examine project.
How to solve these questions?
  • When choosing the rail bolt, it’s better to choose the reliable company. AGICO RAIL as a china railway bolts factory with an approved license from China’s Railway Ministry to produce railway products. We would like to provide the track bolt free sample for you at first. 
  • Find the professional team to install the rail bolt or find a professor to teach the workers. Meanwhile, it is better to clarify the installation standards and provide the professional tools.

Rail Bolt Fracture

With the development of the railway system, the alloy steel combination frog overcomes the technical shortcomings of high manganese steel casting frog, like not easy to weld. Meanwhile the alloy steel combination frog can improve the material hardness and wear-resisting property. Compared with the high manganese steel casting frog, the alloy steel combination frog has many parts and a looseness structure. In order to ensure the stability of the structure, it needs more rail bolts to fasten. The rail bolts should maintain a high torque and keep the origin shape under the pressure of the train.

How to solve this question? We did a test to study it. According to the result, we find that the longer rail bolt and the more parts will cause the rail bolt bears much force. Besides, we find that if the torque less than 600N.m, the rail bolt cannot combine other parts tightly.

Under the 250KN force of the wheel, the vertical displacement of the rail in addition to the elastic deflection, the parts will have a sliding displacement at the interface, and then the rail bolt is squeezed and produces bending stress. When the torque less than 400N.m, the rail bolt will be cracked. So our conclusion is the torque should not less than 500N.m.
Besides, if you have other questions about the rail bolt, welcome to contact AGICO Rail. As a professional track bolt manufacturer, AGICO Rail has the ISO9001-2000 certificate and a professional team and track bolt factory in China. AGICO RAIL promises our products are high-quality and our service is the best!

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