Why Railroad Spikes Will Be Corroded?

Railroad spike is easy to be cracked. In order to figure out the reason, We do  a study for railroad spike corrosion, why railroad spike will be Corroded?

          What are the components of rail fastening system?

What Are The Components Of Rail Fastening System? 

A list of rail components for track, including rail, railroad tie, rail joint, rail fastening system and railway switch. See how these parts work together….

5 common railway components for track

        5 Common Railway Components For Track     

  A list of rail components for track, including rail, railroad tie, rail joint, rail fastening system and railway switch. See how these parts work together….        

   What are the components of rail fastening system?

  What Are The Components Of Rail Fastening System?      

      7 main parts of rail fastening system: rail clip, tie plate, railroad spike, insulator, rail pad, etc. Customized Design and Fast Shipping are available….     

  How rail clips are made?

        How Rail Clips Are Made?       

See how rail clips are made. Specific process: raw material- shearing- heating- forming- hardening- tempering- inspection- packing

Rail connection overview-part 2: rail fastening

Rail Connection Overview-Part 2: Rail Fastening

An overview of rail fastenings including railroad spike, rail clip, tie plate and rail pad, etc. introducing how to connect rail and railway sleeper together….

Rail connection overview - part1: rail joint fastening

Rail Connection Overview – Part1: Rail Joint Fastening

A brief overview of rail connection, listing some rail joint fastenings like rail joint, fish bolt and etc. sum the connection between rail and fastenings….

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What are the components of rail fastening system?

What Are Th gy by bye Components Of Rail Fastening System?

7 main parts of rail fastening system: rail clip, tie plate, railroad spike, insulator, rail pad, etc. Customized Design and Fast Shipping are available….



4 Plastic And Rubber Parts Of Railway Line

plastic and rubber parts Excepting for iron parts like railway fish platerail clipscrew spiketrack bolts, there are some plastic and rubber parts in the construction of railway track, such as rail pad, plastic dowel, rail insulator, guide plate. Do you really know these rail fasteners? Let’s figure them one by one.

Rail pad

Rail pad, also known as rail rubber pad, is used between steel rail and concrete sleeper. The main functions of rail pad can be divided into three aspects: absorb vibration caused by vehicle, protect rail base and railway sleeper, electrical insulation of signaling system. Due to long-term exposure to the air, rail pad is required good performance in aging resistance, cold resistance and hot resistance. For the subway, the rail pad must have better vibration reducing and low-noise performance. The rail rubber pad can greatly improve the transportation ability of vehicles, reduce the maintenance of railroad grade crossing, and avoid traffic accidents caused by motor vehicles flamed out. No matter from the aspects of safety, economy, environmental protection and social benefits, it is worth popularizing and applying. rail pad

Rail plastic dowel

rail plastic dowel The rail plastic dowel is a pre-embedded assembly, it is usually fixed in the pre-products (such as cement sleepers, bridges, buildings, etc.), and the threads on its surface are fused with the preform. In general, plastic dowel is used with the rail bolts or screw spike, for fastening other objects. Material: nylon glass fiber (PA66 + GF), plastic (HDPE), and so on. Nylon dowel is made of glass fiber reinforced nylon composite material by injection molding process, both internal and external have screws. A: The internal scew matched with the screw spike is a serrated single beveled screw, the oblique side of the screw is a large bevel, and the fit between the nylon sleeve and the spike is a loose fit, so that the plastic sleeve and its components have optimal stress condition, which greatly extends the service life of rail nylon sleeves and their components;

B: The external screw combined with the concrete sleeper is a screw groove with the same pitch and internal screw. According to the road condition, it can be full or semi-threaded. At the same time, a horizontal boss is added to the upper and lower ends of the sleeve, and an insertion hole is arranged in the boss, which facilitates the insertion of the steel bar when being embedded, and improves the pullout resistance of the sleeve to the sleeper. It can be widely used in concrete engineering projects, such as railways, highways, bridges, houses, etc. It is especially suitable for railway sleepers. It is embedded in the concrete sleeper to increase the speed of the train and improve the speed of the turnout.

  • The production process: injection molding by injection molding machine, and it is similar to the production process of the gauge block.
  • Features:Plastic dowel use high-quality nylon 66 as the base resin, it is blended and granulated by adding various modifiers. It has good mechanical strength, heat resistance, wear resistance, high rigidity and good pull-out resistance. With the advantages of simple and convenient construction, long service life, etc. It can improve the durability, insulation, environmental protection level and comprehensive technical and economic indicators of the sleeper, and meet the requirements of high-speed railway development.

Technical requirements

Properties Units Test methods TEP-DBZ730
Density g/cm GB1033 1.14
Tensile   strength MPa GB1040 ≥55
Elongation % GB1040 ≥70
Flexural   strength MPa GB1042 ≥65
Flexural   modulus MPa GB1042 ≥2000
Notched Impact Strength 20℃ KJ/m GB1043 ≥25
-50℃ KJ/m GB1043 ≥15
Hardness R GB9342 ≥95
Absorptivity % GB1034 ≤1.3

Rail insulator

Rail insulator is an important railway fastener for connecting rails and rails. The rail insulator achieves its reliability and stability, while ensuring the flexibility and rigidity of the normal operation of the track. As one of the key components of high-speed railway fastener system, rail insulator is a kind of fastener suitable for rail and sleeper connection in railway line. rail nylon insulator Feat​ures: high mechanical strength, heat resistance, wear resistance, high rigidity, dimensional stability.


How To Choose Railroad Spike?

railroad spike


The railroad spike is used to fasten railway track, it fix the steel rail to the rail base. As the common types of railway fastener in railway transportation, the railroad spike has been created earlier and ungraded along with the continuous development of railway track. 

At present, the commonly used railway spikes in China include screw spikes, wooden thread spikes, and dog spikes. These types of railroad spikes are used in different ways, but their functions are same.

For some new buyer, the first question is how to choose suitable railroad spikes from all types of railroad spike. To solve this problem, we learn each type of railroad spike one by one. 

Screw spike

The screw spike is usually made of steel No. 3. Because the surface of the nail rod is threaded, it is called a screw spike. Its pull-out resistance is 0.5 to 1.0 times larger than that of ordinary railroad spike, but the thrust resistance is 50% less. Due to the inconvenience of disassembly and assembly, it is difficult to adjust the gauge distance, and it is generally applied to the railway switch. 

screw spike

Technical requirements of screw spike

  1. The material of the screw spike is Q235-A steel.
  2. The upper thread of the screw spike is M24, the basic size should meet the requirements of GB196, and the thread tolerance is made according to the 8g specified in GB197.
  3. The lower thread of the screw spike is special M25.6×6—d24.0/25.6 thread, and the tooth height is 3.25—00.25mm.
  4. The end of the screw spike is manufactured in accordance with the provisions of GB2.
  5. The forged burst crack on the surface of the head of screw spike is not allowed to extend to the shaft.
  6. The upper thread of the screw spike is not allowed to have the bumps and burrs that hinder the screw gauge from being screwed in. The double cusps and scratches are not allowed to be exist.
  7. The lower thread of the screw spike should be neatly shaped, the thread is complete, and no cracks are allowed.
  8. The surface of the screw spike is not allowed to have dents, burrs, flash, burns and scales that affect the use.
  9. The screw spike should be subjected to the physical tensile test. When the load is 130kN, the screwl spike should not be broken. 

Dog spike

Common railroad spikes, also known as hook spikes or dog spikes, are mainly used for the connection of rails or rail pads and wooden sleepers. Ordinary railroad spikes are made of No. 3 hot rolled steel(GB standard). The cross section of the shank is a square of 16 mm on each side and the nail length is 165 mm. The head of the spike is in the shape of a mushroom, and the shape of the lower part of the nail head is adapted to the shape of the bottom of the rail. The surface of the shank shall be smooth and clean, the flash edge shall not exceed 2 mm, and the displacement of the shank relative to the center line of the nail head shall not exceed 1 mm in any direction. There must be no cracks at the joint between the nail head and the shank. The top of the spike is chisel-shaped, and the chisel is perpendicular to the wood grain to avoid splitting the wooden pillow. The tip edge is straight, and the top end does not allow burrs or folds that affect the use. There should be no air bubbles and excessive burns and cracks that hinder the use on the surface of the spikes. 

dog spike

  • The ordinary railroad spikes are divided into manual spikes and mechanical spikes. These two kinds of spike are the simplest in the process of installation and use, and can be directly fixed by using a nail.
  • However, these two types of railroad spikes are very different in terms of production process. The manual spikes are a relatively early production for railroad spikes. This production uses the method of hand-made to make sure the hot embryo forming of railroad spike, so the railroad spikes manufactured by this production process may have certain defects, for example, the surface of the spikes may have some convex or burrs. There are also some spikes that have more or less weight. 
  • Compared with manual spike, another common railroad spike can avoid these problems very well, that is, the mechanical spike. The production process of mechanical railroad spikes is a combination of manual and mechanical production. Commonly, the mechanical railroad spike has a smooth surface and the weight of each spike is not much different. The mechanical railroad spikes can be better used in batches, and the problem of high defective products like ordinary manual spikes does not occur.
  • Manual spikes and mechanical spikes are similar in the installation and maintenance process during use, but the mechanical spikes have strict standards and no defective requirements. At the same time, the nails of the mechanical spikes are smoother, which makes it less prone to accidents during transportation, so it is very popular among railway workers.

Manual spike

Manual spikes are a type of ordinary railroad spikes. It is generally synonymous with low-cost process, but it is undeniable that the use of such inexpensive spikes in many gentle railway sections is easier to maintain and replace. At the same time, the low cost of production also makes the manual railroad spike become a rare product that can be shipped in tons among railway accessories.

Mechanical spike

As another type of the ordinary railroad spike, the production process and raw materials of the mechanical spike are generally superior to the manual spike, so the production cost of the mechanical spike is correspondingly higher than that of the general manual spike. At present, the safety of the production and use of railway accessories is receiving more and more attention. Many railway lines have adopted the use of safer railway accessories such as mechanical spikes.

The mechanical spike is the same as the general spike in use. Therefore, the maintenance can be easily replaced by using the corresponding dowels, rail hammers and other spike mounting devices during use, which greatly facilitates the maintenance of the railway.



How Much Do You Know About Railway Sleepers?

The railway sleeper is a type of railway accessory. The railway sleeper not only supports the steel rail, but also maintains the position of the rail, and transmits the huge pressure transmitted by the rail to the track bed. It must have a certain degree of flexibility and elasticity. When the train passes, it can be properly deformed to cushion the pressure, but the train must be restored as much as possible.

The railway sleeper was originally made of wood. The elasticity and insulation of the wood is good. Wooden sleeper is less affected by the temperature change of the surrounding medium, light weight, easy to replace on the processing or on the railway line, and it also has sufficient displacement resistance. After the anti-corrosion treatment of the wooden sleeper, the service life is also greatly extended, about 15 years. Therefore, 90% of railway lines in the world use wooden sleepers. With the reduction of forest resources and the increase of people’s awareness of environmental protection, of course, due to the development of science and technology, at the beginning of the last century, some countries began to produce steel railway sleepers and reinforced concrete sleepers to replace wooden sleepers. However, because the metal consumption of the steel sleeper is too large, the cost is high, the volume is cumbersome, and it has not been promoted. Only a few countries such as Germany are still using it. In many countries, reinforced concrete sleepers have been widely produced since the 1950s.

Wooden sleeper

wooden sleeper


The wooden sleeper is made of wood, also known as sleeper wood, anti-corrosion wooden sleepers, also known as oil-filled sleepers. Tough and flexible wood must be used for making wooden sleepers. Wooden sleepers can be divided into ordinary wooden sleeper, squat sleepers and bridge sleepers according to their use.

However, due to the material, the elasticity, strength and durability of the wooden sleeper are not uniform enough, which will increase the wheel-rail dynamics and consume a large amount of high-quality wood. The wooden sleeper has a short service life and has many causes of failure, mainly include decay, mechanical wear and cracking. Because the wooden sleeper is easy to decay, in order to effectively extend the service life, the sleeper must generally be used after oiling and anti-corrosion. The wooden sleeper without preservative treatment is called a plain pillow. China’s timber resources are relatively scarce and expensive, and have been gradually replaced by concrete sleepers on major railway lines.

Advantages of wooden sleepers

  • Good elasticity (not easy to break), light weight, simple production, good insulation performance, low price, simple connection between rail fastening system and wooden sleepers, convenient for laying, processing and transportation;
  • There is a large coefficient of friction between the wooden sleeper and the gravel ballast;
  • The sleeper has good plasticity and can be processed according to the actual situation, with less waste.

At present, China’s standard railway gauge is 1435mm. The standard wooden sleeper specifications are as follows:

  1. Ordinary sleepers: width 220mm; thickness 160mm; length 2500mm;
  2. ballast sleepers (ordinary): width 220mm; thickness 160mm; length 2600 ~ 4850mm, with 150mm carry, a total of 16 length specifications;
  3. ballast sleepers (standard): width 240mm; thickness 160mm; length 2600 ~ 4800mm, with 200mm carry, a total of 12 length specifications;
  4. bridge sleepers: width 220mm; thickness 240, 260, 280, 300mm; length 3000mm.

Concrete sleeper

concrete sleeper

Concrete sleepers are concrete products used as railway sleepers. The concrete sleeper is stirred by cement, sand, stone, water and admixture in a certain proportion, synthetic mixture is injected into the combined model of the sleeper fittings with steel wire or steel bar, using vibration forming or vibration forming, steam curing and relaxation, cutting sleeper ends, and other ways to make concrete sleepers.

The concrete sleeper has the advantages of saving wood, long service life, good laying track quality, less maintenance and low cost. The damage rate and scrap rate are much lower than that of wooden sleepers. The application on high speed, heavy load, seamless and other railways is significantly better than wood, and the stability is increased by 15~20% on average. Therefore, it is especially suitable for high speed passenger lines. For example, Japan’s Shinkansen and Russia’s high-speed trunks all adopt concrete sleepers.

  • According to the structure, it is divided into integral type, combined type and semi-sleeper;
  • It is divided into reinforced concrete sleeper and prestressed reinforced concrete sleeper according to the way of reinforcement;
  • According to the prestressing application method, it is divided into pre-tension method, post-tension method and continuous reinforcement method;
  • The gauge is divided into 1435mm standard gauge and 600, 762, 1000mm narrow gauge concrete sleepers.

Steel sleeper

steel sleeper


Steel sleepers have been widely used on the federal German and Swiss railways. However, since the steel sleeper is apt to be rusted, the consumption of steel is large, the maintenance cost is high, and the amount of use is gradually reduced.





Steel Rail Type Overview

steel rail

Steel rails are known to be an integral part of railway tracks. Steel rail and other railway fasteners support the railway track system, including railway sleepers, rail joints, railroad spike, rail clips, track bolt and nut, etc. The steel rails are always in an inconspicuous place for the train to crush and guide the train. The modern steel rail is made of steel. Rails were not like this at the beginning of their birth, or even the current material. At first it was a piece of square wood, and later the wood was covered with iron wrap. As the speed and weight of the train increase, the material of rails becomes steel step by step. In modern times, with the increase of train speed and axle weight, the improvement of the requirements for stability, the improvement of production and manufacturing processes, the classification of rails is becoming more and more detailed.

Steel rail types

There are many ways for steel rail classification, such as weight, application, international standard, and etc.

Classified by weight

The type of steel rail is usually divided by weight. For example, we often say a 50kg rail, which means rails with a weight of 50kg/m, and so on. There are 38kg rails, 43kg rails, 50kg rails, 60kg rails, 75kg rails, etc. There are also 24kg rails and 18kg rails, of which rails of 43 rails and above are generally called heavy rails, otherwise, the steel rails weight below 43kg are called light rail. There is a special kind of steel rail that is called crane rail. Crane rail is used for crane railway.

Classified by international standard

For meeting various sizes of different countries around the world, steel rail can be process according to international standard, such as GB, AREMA, BS, UIC, JIS, DIN, AECE, and etc.

Classified by manufacturing process

According to the manufacturing process, the steel rail is mainly divided into hot-rolled rails and heat-treated rails. In fact, all of the rails are produced by the hot rolling process. The heat-treated rails are reheated after the hot-rolling process, which are divided into online heat treatment and offline heat treatment. The online heat treatment is already mainstream, which is more energy-saving and more efficient. Classified by intensity The steel rail is a complex alloy, in addition to the main component iron (Fe), there are five major elements, carbon (C), manganese (Mn), silicon (Si), phosphorus (P), sulfur (S), of course, there will be some decisive role of the trace elements vanadium (V), chromium (Cr), and some rare earth elements, etc., these elements merge with each other, due to different manufacturing processes, resulting in different physical properties of the steel rail.

Classified by rail usage

High-speed railway: The steel rails in the station (that is, the parking lot) use 60 rails (partial parking lines use 50 rails), and the main line (including station lines and auxiliary lines) is also 60 rails, but the steel rails of high-speed railways have higher requirements on flatness, and various sections. The size requirements are higher. Ordinary railway: It is the passenger and freight railway before the completion of the high-speed railway (now still operating), the depot and parking lot use 50 steel rails, and the main line use 60 steel rails. Heavy load railway: Similar to the Daqin, Yuhuang Railway and Shenhua Coal Transportation Line, it is characterized by a large train axle and a large total weight. The load of a train can reach more than 10,000 tons (for comparison, the average subway is about 100 tons). This type of railway generally uses a specially manufactured 75-rail, which can greatly increase the service life. High-cold railway: Specifically, the Qinghai-Tibet line, which passes through the permafrost zone, has high requirements for cold resistance and corrosion resistance of the steel rails, and uses a specially manufactured 60 rail. Subway: The domestic subway is now basically 50 rails for the parking lot and 60 rails for the main line. Of course, the long-term subway main line uses 50 rails. Tram: Because of the small size of the wheel, the small turning radius, and the small number of the turnout, the tram is easy to derail, so the grooved rail with its own guard rail is selected.


Fast Clip Fastening: A Trend Of Rail Fastening System

fas clip fastening system

The fast clip rail fastening system is a new type of rail fastening system, which represents the latest level and development direction of railway fastener technology, and it has been widely used in the railway of Europe (CEN), Germany (DB-AG), France (SNCF), Japan ( RTRI), Australia (AS) and North America (AREA) and other countries. The fast clip railway fastening system is also introduced and applied to the railway line in China. The two sections of Hefei Passenger Dedicated Line, Shitai Passenger Line will adopt such rack fastener system.

FC rail fastener system is always used for the ballasted track. It has been widely used in some high-level railway lines in Europe and America, such as the French TGV high-speed railway line, with a design speed of 350KM/h. It has also been widely used in the Japanese Shinkansen in Asia and the high-speed railway in South Korea, and the effect is good.

About FC rail fastening system

Fc fastener system composition and main technical requirements:

  1. Flexible separation;
  2. no shoulder;
  3. With railroad tie plate;
  4. No track bolt buckle;
  5. No adjustment of the height;
  6. The elasticity is not separated;
  7. The gauge adjustment is -8 ~ +4mm;
  8. Buckle pressure is 10kn;
  9. The range of 12mm;
  10. Static stiffness: 80 ~ 100kn / mm.

The FC fastener system is shoulder-free and bolt-free fasteners, it has less spare parts, compact structure and strong track-keeping capability. The base is pre-embedded when the concrete sleeper is made, and the elastic clip is pressed against the rail by inserting the embedded base. An insulating rail gauge block is arranged between the embedded base and the steel rail, and the left and right positions of the rail are adjusted by replacing the insulating gauge block. This rail fastener cannot be adjusted for rail height.

Fastener composition

fast clip rail fastening system

  • The Fc fastener system consists of a fast clip, an insulating cap, a pre- embedded base, an insulated gauge block and a rail rubber pad.
  • Fast elastic clips are divided into Fcl504 type, Fcl502 type and Fcl306 type. Fcl504 type rail clip (15mm in diameter with 8494 insulating cap) is installed in the general section. FCl502 type elastic bar (15mm in diameter and no insulating cap) is installed at the splint. FCl306 type elastic bar is installed in the small resistance area (diameter is 13mm with 12133 type insulating cap).
  • Insulation gauge blocks have a total of 10 specifications, respectively, 6 to 15 mm thickness.

Main technical requirements

  • The sum of the gap between the rail and the insulation gauge block, or the gap between the insulation gauge block and the embedded iron seat should not exceed 1 mm.
  • The pressure should not be less than 9kN (small resistance clips should not be less than 3kN).
  • Distance adjustment: -8 to +8mm, the rail gauge and rail adjustment are made by replacing the insulation gauge blocks of different numbers.
  • Low adjustment: the fasteners cannot be adjusted in height, and the rail pad should not be raised.
No. Item Performance Index
1 Applied rail type GB standard 60kg steel rail
2 Rail gauge 1435mm
3 Rail bottom slope 1:40 rail bottom slope is placed on the railway sleeper
4 Longitudinal resistance of rails In general, the longitudinal resistance of each set of rail fastener and rails is larger than 9kN;
5 Elasticity of rail fastening system The rail pad has a static stiffness of 50 to 70 kN/mm.
6 Fatigue performance  After 3 million load cycles, the fastener system has no damage, and the buckle pressure changes is less than 20%; the longitudinal resistance of the rail changes is less than 20%; the static stiffness of the joint changes is less than 25%.
7 Insulation resistance The fastener system is tested according to EN13146-5, and the insulation resistance between the two rails is greater than 5kΩ.
8 Harsh environmental conditions The fastener system can be successfully disassembled with a manual disassembly tool after the 300h salt spray test described in EN13146-6.
9 Adjustment amount between left and right of rail The adjustment of the left and right position of the single-strand rail: -4~+2mm;
Rail gauge adjustment: -8 ~ +4mm, adjustment level is 1mm.
10 Rail height position The adjustment amount is 0mm.
11 Buckle pressure and spring range FC1504 type spring bar: buckle pressure is 10kN, spring range is 12mm;
FC1306 type spring bar: buckle pressure is 3kN.
12 Pulling resistance of the embedded parts pulling resistance of the embedded iron seat in the railway sleeper is not less than 60kN.


7 Requirements For Rail Fastening System Of Passenger Railway

requirement for rail fastening system

Railway fastening system is used to fix steel rail and railway sleeper, it usually consist of rail clips, tie plate, screw spike, rail pad, rail insulator, rail plastic dowel, etc. There are various types of rail fastening system for meeting different requirement of various railway section, such as SKL rail fastening system, E-clip fastening system, KPO fastening system, Nabla fastening system.

Due to the passenger dedicated line is mainly aimed at comfort and safety, the passenger dedicated line has no need for a single sub-structure. It involves various structural foundations such as bridges, tunnels and subgrades, and must meet operating conditions. The requirements of the following key technical issues of the fastener system need to be considered.

Good vibration damping performance

The ballastless track fasteners should have better elasticity than the ballasted track fasteners, but the elasticity cannot be increased without limitation. Otherwise, the rails will be tilted too much when the train passes, and the dynamic gauges will affect the smoothness. There are two key technologies to be studies, firstly, matching the stiffness of the rail fastening system and the track stiffness. Secondly, both lower stiffness of rail fasteners and driving safety are all considered.

High insulation performance

According to the requirements of the track circuit, the rail fastening system has high insulation performance not only under dry conditions, but also in case of heavy rainfall. It requires special technical measures to improve the water film resistance of the rail fastening system.

The versatility of rail fastening system on continuous welded rail

Due to the requirement of continuous welded rail laying, the fastening system in the tunnel or on the roadbed should have sufficient anti-climbing resistance. In the normal situation, the greater the anti-climbing resistance is, more beneficial to the continuous welded rail, so the elastic clip with large buckle pressure is often used to buckle the rails. In order to meet the requirements of laying continuous welded rail, the bridge fastener system usually adopts a small resistance elastic fastener, in other word, use rail clip with a small buckle pressure and a composite pad with a lower friction coefficient to buckle the rail. Therefore, for the rail fastening system installing, a rail clip with large buckle pressure or small buckle pressure are both available.

The versatility of the rail fastening system on various ballastless track

Various ballastless track structures are different, but the rail fastening system is versatile from the perspectives of design, construction and operation management. Whether the sleeper buried ballastless track or the slab ballastless track, the rail fastening system should be installable, that is, the rail fastening system can accommodate a variety of different types of ballastless track structures.

Deduction of buckle pressure and fatigue life

The stiffness decrease of the rail pad under the track means that the train has a large deformation when it passes, and the dynamic deformation of the front end of the elastic clip is increased, which require the elasticity and fatigue performance of the elastic clip. The buckle pressure reductions of rail clip under the lower stiffness rail and fatigue life are two problems.

Reliable connection between the rail fastening system and the foundation

The ballastless track fastener generally adopts an elastic split fastener with an iron tie plate. According to the functional requirements, the iron tie plate is fastened to the foundation by the anchor bolt and the pre-embedded insulating sleeve (also called plastic insulating dowel) in the concrete foundation. According to the previous engineering practice, the strength and fatigue life of the embedded parts in the concrete foundation are weak links. Taking measures to effectively improve the strength and fatigue life of the pre-embedded insulating dowel is one of the problems to be solved.

Fewer spare parts and convenient operation mode

Fewer spare parts and convenient operation mode achieve high and low position adjustment of the rail. Summarize the practical experience of  ballastless track engineering, the rail height and position adjustment amount is large and fine adjustment is required. Therefore, the rail fastener system structure adopted should have a mode with less spare parts and convenient operation to adjust the height and the positions of the rail. When making the left and right position adjustment, try not to replace the parts, and the adjustment mode is preferably stepless adjustment.


What Do You Know About Rail Pad?

rail pads

Rail pad, also known as rail rubber pad, is a necessary part of railway track fasteners. Generally, rail pad is installed between steel rail and concrete railway sleeper. The rail pad is mainly used to reduce the high speed vibration and impact produced by the vehicle during running. Rail pad protect the rail base and railway sleepers, electrically insulating the signal system. Because long-term explosion in the sir, the rail rubber pad is usually required to have properties of ageing resistant, cold-resistant,  heat-resisting. The rail pad for subway also requires good damping performance and low noise.



Comparison Of Railway Sleepers

railway sleepers The railway sleeper is one of the important foundations of the railway track. It is used to carry the weight of the train and pass it to the rail bed. This paper classifies the railway sleepers according to the materials, describes their performance characteristics, and focuses on the research and analysis of the use of several composite sleepers that have appeared in recent years. The wooden sleeper is the first type of railway sleeper used in the railway, especially the pine sleeper, which is used more often, and later concrete sleepers appeared. However, on the railway steel bridge, due to the poor elasticity of the concrete sleeper, it cannot be used, and only the wooden sleeper can be used. Although the wooden sleeper has good elasticity, it has a short service life and frequent replacement. Therefore, it is necessary to study a new type of sleeper – composite sleeper for the steel bridge. In recent years, several composite sleepers have been researched and produced using new technologies and processes at home and abroad. These composite sleepers include FFU synthetic sleepers, polyurethane composite elastic sleepers, integral coated recycled rubber composite sleepers, composite rubber elastic sleepers and so on. This paper compares the performance of wooden sleepers, concrete sleepers and several composite sleepers.

Performance comparison

Wooden sleeper

The performance advantages of wooden sleepers include light weight, good elasticity, good insulation performance, simple production, convenient transportation and maintenance, etc. But there are disadvantages of short life, frequent replacement, large consumption of wood, and A large number of human and financial resources and material resources consumption per replacement. Orbital geometry is also not easy to maintain and other shortcomings. wooden sleeper  

Concrete sleeper

The performance advantages of concrete sleepers include the less affect by climate or decay, warranted size, uniform elasticity, good stability, long service life, less maintenance and repair times, low cost. In addition, higher track bed resistance of concrete sleeper is very beneficial to improve the lateral stability of the seamless line; however, its disadvantages include heavy weight, poor elasticity and insulation performance. A buffer insulation layer is required at the bottom part of the rail, and the rail joint parts are complicated. It is more difficult to replace. concrete sleepers

FFU synthetic sleeper

FFU synthetic sleeper, referred to as long glass fiber reinforced foam polyurethane. A long glass fiber and a hard polyurethane resin are used as a main component, and a molded plate compress and bond to frm the synthetic sleepers. Compared with other materials, this material has high corrosion resistance, fatigue resistance, electrical insulation resistance, long service life, up to 50 years, low replacement frequency, and can reduce cycle cost. And the FFU synthetic sleeper is light in weight, its weight is only 1/3 of the concrete sleeper, and its waste can be recycled after being crushed and pressurized to make a new recycling product.

Polyurethane composite elastic sleeper

Polyurethane composite elastic sleeper, the structure is divided into inner core and peripheral layer. The inner core is made of strong – concrete core such as full-grain FRP, and the FRP steel bar made of high-performance fiber such as glass fiber, it has the advantages of light weight, high strength, fatigue resistance, corrosion resistance, etc. The pre-stressed concrete core is characterized by high strength, high ductility, good corrosion resistance, good insulation and long service life. The peripheral layer is made of a material such as a glass long fiber reinforced polyurethane resin foam, and the long glass fibers are uniformly distributed in a monofilament shape, and the foam maintains completely independent bubbles. The peripheral layer has the characteristics of high strength, good elasticity, insulation and corrosion resistance. The composite sleeper has good shock absorption and noise reduction performance, corrosion resistance, good insulation and service life of more than 50 years.

Coated reclaimed-rubber composite sleeper

The coated reclaimed rubber composite sleeper, the structure is also composed of the inner core and the outer layer, and then integrally molded by special equipment. The inner core structure of composite sleeper is divided into a w-groove inner core structure and a wooden core type structure. The w-groove inner core structure is composed of a w-shaped groove, a fixed nail block, and concrete. The inner core of the w-shaped groove is pressed from the steel plate to take the leading load. The fixing block is made of composite material, it is installed on the bearing part to facilitate the installation of the fastener system and increase the elasticity of the sleeper. Fill the concrete material in the spare part of the groove to enhance the load bearing capacity and increase the stability. The wooden core structure is divided into old wooden sleeper repair type, new wooden sleeper type, and wood powder composite type.

  • The old wooden sleeper repair type repair the old wooden sleeper, and the old wooden sleeper is covered by special equipment to make it renewed, thereby prolonging its service life;
  • The new wooden sleeper type process wood into a certain inner core according to needs, and do the outer layer coating treatment directly, try to avoid the shorts of traditional wooden sleeper, such as putrescibility and crack, prolong the service life, and the wood is no longer required to be treated with antiseptic treatment, thereby eliminating the environmental pollution of the preservative and the harm to the human body;
  • The wood powder composite type is obtained by blending wood waste, wood powder and other polymer composite materials to form an inner core, and then coating the wood to achieve the purpose of saving wood. The peripheral layer is made of recycled polymer rubber composite materials by special process such as waste tires and waste plastics. After the inner core of the sleeper is fed into the special equipment by the tractor, the composite material is continuously and automatically coated on the inner core surface, and the sleeper coating layer is formed at one time without joints in the middle, greatly improving the reliability and the service life, reducing the production cost and maintenance costs.

Recycled rubber-plastic composite material has the high elasticity of rubber and the high strength of plastic, so that its outer layer has the advantages of good elasticity and high compressive strength, so as to cope with the dynamic effect of train wheel and rail in railway transportation; at the same time, it can absorb noise. reduce vibration and make the track structure more stable.

Composite rubber railway elastic sleeper

How are composite rubber railway elastic sleepers made? combines waste plastics, waste paint and recycled rubber powder made of waste tires to plasticize and blend, and then extrude a new material-recycled rubber-plastic composite material. The property of material is close to wood, but the strength, elasticity, corrosion resistance and processing performance are more than wood. Compared with the existing wooden sleeper and concrete sleeper, the composite sleeper has good insulation, shock absorption and noise reduction performance, low installation and maintenance cost, long service life and high comprehensive cost performance.

Analysis of the cost and application

  • The raw materials of wooden sleepers are mainly pine and other materials with good quality. The price of a wooden sleeper is about 230-270 yuan, but the wooden sleeper has a short service life and frequent replacement. Due to the lack of wood resource and large consumption, the wide application of wooden sleepers has become a thing of the past.
  • The main component of concrete sleepers is cement. The production cost is low. The price of a concrete sleeper is about 75-90 yuan. There are many material resource of concrete sleeper. With relatively rapid development and application, at present, China’s railways basically adopt concrete sleepers.
  • FFU synthetic sleepers are widely used in Japan, but the cost is high. The price of a FFU synthetic sleeper is calculated to be more than 2,500 yuan. The composite sleeper is experimentally researched in China. It has a production line in Shanghai, but it is not used on Chinese railways. Just like FFU synthetic sleeper, the cost of Polyurethane composite elastic is high, and they are not yet used on the Chinese railway. The whole coated reclaimed rubber composite sleeper has many production processes and high cost. It has been developed and produced in Qingdao, China, and has been exported to the United States, India, Chile and other countries, but has not been used on Chinese railways; Composite rubber railway elastic sleeper has low cost, but the process is more complex, widely used in the US first-class railway and short-distance railway. The products have been used in railway construction projects in Australia, India, Thailand and other countries, but have not been used on Chinese railways.

The sleeper is an important part of the railway. In China, the railway sleeper is mainly made up of concrete sleepers, and the wooden sleepers are used on the steel bridge. Due to the lack of wood resources and the short service life of the wooden sleepers, it is necessary to study the composite sleepers on the steel bridges, compared with the wooden sleepers. Concrete sleepers and composite sleepers meet the requirements of railway construction development in terms of performance and recyclability. They will bring both huge economic profits and far-reaching environmental benefits. With the development of science and technology, adopt new materials, new processes and new technology, the research and application of composite sleepers will become more and more extensive, and will certainly become the development direction of railway special section sleepers.