Reinforced concrete products - an alternative to wooden sleepers
The weight of a wooden sleeper is significantly less than its reinforced concrete counterpart and installation, replacement, and maintenance are relatively cheaper.
Despite this, reinforced concrete sleepers make up approximately 25% of the total mass of products. Their production is based on the process of concreting on reinforcement - just like conventional reinforced concrete production. Today, reinforced concrete products are most often used to create urban rail connections, including subways and trams. How much a concrete sleeper weighs is more of a question for comparison; the average weight itself reaches 250 kg, and the weight can vary within 20 kg. Due to the weight and size of reinforced concrete sleepers, replacing these products is difficult, but thanks to the development of modern technology, it is becoming easier every day.
The production of reinforced concrete sleepers involves their long-term operation, since they are not subject to rotting and are resistant to moisture and temperature changes. The negative aspect is due to the fact that over time, minor damage is observed at the joints. This is especially evident where there are special holes for fastening rails, and sometimes in other areas found along the entire length of railway sleepers. Therefore, every year from 300 to 500 thousand units of reinforced concrete products of this type are replaced, respectively, all this multi-ton reinforced concrete block requires special disposal. It remains to clarify existing standards and regulations to resolve this issue.
Video - recycling and recycling of reinforced concrete sleepers. In the video you can see that sleepers are turned into reinforced concrete scrap using a special crushing bucket.
Regardless of whether the reinforced concrete sleeper is manufactured in accordance with GOST 32.152-2000 or for installation on crane tracks of the PShP-310 type, disposal takes place based on the degree of wear of the products, as well as in accordance with FKKO.
Disposal of waste railway sleepers 84100000000 is provided for by a document on the basis of which waste of this type is clearly described and each is assigned its own hazard level. This is mainly 3-4th grade. Therefore, for storage, transportation, and disposal, a waste passport is required.
Modern technologies make it possible to process reinforced concrete products, dividing them into fractions: crushed stone and metal reinforcement (see video above). These types of waste can each be reused in their own category. Crushed concrete is used to add to the creation of new reinforced concrete products, as a material with which to sprinkle paths, etc. Metal parts can accordingly be sent for smelting if there is no other area of use.
Conclusion
Now you know how much a reinforced concrete sleeper weighs, how it is made and what its operational features are. We must assume that the use of these concrete products will be relevant and in demand for a long time.
Indeed, even despite the development of completely plastic sleepers in Japan, it is compliance with GOST for reinforced concrete sleepers that guarantees the optimal combination of strength, durability and reasonable cost. You can find more useful and interesting information by watching the video in this article.
Bridge beams: specifics of standardization
So, we looked at what the standards are that regulate the size of wooden sleepers (WW) and the timber that complements it in the structure of railway tracks. But there is another important component of the corresponding highways. We are talking about bridge beams. Just as the size of railway sleepers is regulated, this indicator for the component of railway tracks in question is also fixed in state standards. Let's study this specificity in more detail.
The material used to make bridge beams is wood. Their size correlates with one parameter - the size of the cross section, as well as permissible deviations. The main requirement for the bars is a rectangular shape. The corresponding elements of railway lines come with the following cross-section:
— 220 by 240 mm;
— 220 by 260 mm.
Both types of bridge beams, however, must have the same length - 3250 mm. But in terms of standardization of maximum deviations, indicators may vary. So, for beams with a cross section of 220 by 240 mm, the maximum deviation can be: minus 2 mm (in thickness), 15 mm (in length). Regarding the second type of railway elements, the indicators are different. Thus, adjustments in thickness for beams with a cross-section of 220 by 260 mm are not provided, as well as in length, but in width the corresponding value, which is established in the standard, is 3 mm.
It can be noted that, by agreement with the customer, beams with other sections can be manufactured - 220 by 280 and 240 by 300 mm, with a length of 4.2 m.
As is the case with the standards governing the size of wooden (railroad) sleepers, the lengths of bridge beams are established for products within a certain moisture level. In this case - 20%. If the bridge beams have higher humidity, then it is necessary to consider the size requirements taking into account the necessary allowances for shrinkage - in accordance with GOST 6782.1-75.
This is interesting
Reinforced concrete sleepers in Russia. Today, there is a certain upward trend in the market for the production and sales of reinforced concrete sleepers, even despite the global economic crisis. According to marketers, positive dynamics in demand for concrete sleepers is expected in the future. Competition between enterprises will also increase – competition for new orders and new customers. This competition forces us to pay the utmost attention to proposals for the supply of reinforced concrete sleepers. We do not pursue excessive profits, therefore, by contacting our company you will receive the most advantageous offer that corresponds to the present time. Our prices become most relevant when supplying reinforced concrete sleepers to the central regions of the Russian Federation.
Sleeper Ш 1
These reinforced concrete sleepers are intended for the construction of a general network of 1520 mm gauge railways and are produced in accordance with GOST 10629-88. Reinforced concrete sleeper Ш1 (1Ш 27-ВР1500-КБшз) - used with rails of type Р75, Р65, Р50 with rail fastening type KB (separate clamp-bolt type) with bolted attachment of the gasket to the sleeper (separate type Ш1). The sleepers are reinforced with BP II wire, 3 mm in cross section.
Technical characteristics of reinforced concrete sleepers type 1Sh 27-VR1500-KBshz:
- Product weight - 0.270 tons.
- Concrete volume - 0.108 cubic meters.
- Concrete class - B40
- Concrete grade for frost resistance - F200
- Length - 2,700 mm, width - 300 mm, height - 230 mm.
Manufacturers of sleepers: a modern factory of reinforced concrete sleepers offers supplies of its products!
The modern plant of reinforced concrete sleepers offers supplies of its products at competitive prices. Sleeper manufacturers ship these products by rail; the loading rate for one gondola car is 240 pcs and 256 pcs.
Successful production of reinforced concrete sleepers 1Sh 27-BP1500-KBshz is achieved through the use of modern high-tech equipment and the use of high-quality raw materials. The maximum production capacity corresponds to 30,000 reinforced concrete sleepers per month.
The manufactured products are certified and meet the highest quality!
Cost of sleepers: reinforced concrete sleeper Ш1 – price from the manufacturer!
The main advantages of our products are the low cost of sleepers. excellent quality, high production capacity.
Our offer, reinforced concrete sleepers, compares favorably with prices for similar products from other companies. We are confident in the quality and reliability of the reinforced concrete sleepers we supply; the price list for reinforced concrete sleepers can be found in a special section on our website.
For questions related to the purchase of reinforced concrete sleepers, please contact the sales department of SBT LLC by tel/fax; 960-14-40.
Sleeper weight | Simple and reliable with UralSpetsMetall LLC
Our company unites more than 10 enterprises in Russia that produce materials for the upper tracks of railways.
We ourselves produce, store, transport and sell everything that is needed for the construction and repair of railway tracks, both main and secondary. In this regard, our prices are currently the most competitive and attractive to our competitors. Our goods are delivered to any point in Russia, while transport costs for our customers will be minimal because there are warehouses with our goods in every region of Russia. The delivery time for goods is from 2 to 10 working days. Welcome to our company website. You can buy rails from us at competitive prices using the convenient management interface of our online resource. Favorable prices, competent specialists, the opportunity to come and see everything for yourself - these are the criteria for cooperation that you will receive today.
Actually, rails are steel beams that are used to build roads through which special-purpose vehicles and equipment will move. Thanks to our rails, you can build tracks in production workshops and hangars, factories and warehouses. This will make it possible to set up conveyor production, implement the delivery of goods and raw materials, and organize the arrangement of indoor workplaces.
Rolling stock that will move along a double-line track, consisting of rails, will be a good money saver. This is due to the fact that electric locomotives of railway trains are powered by electrical energy, which makes the process economical and provides the equipment with great traction force. The latter circumstance makes it possible to lay entire tracks between production sites and government railway tracks, which makes it possible for freight trains to enter here for loading. By the way, instead of production workshops there may be a sawmill and a place for storing bulk materials, since, for example, granite crushed stone is delivered in this way.
Rails from our company are sold openly and with a quality guarantee for our own products. This happens thanks to extensive experience and the selection of high-quality raw materials. We guarantee that we will ensure straightness of our products in horizontal and vertical planes, calculate the exact chemical and raw material composition of the metal, and also, if necessary, manufacture rails according to your technical specifications.
We produce various types of rails, among which it is worth highlighting heat-strengthened ones, which allows the use of these products both in severe frosts and in conditions of great overheating from excessive friction during frequent use. Quality control of rail production allows us to exclude defects, carry out flaw detection, and organize branding of metal surfaces. All this gives you the opportunity to receive rails in stock or on order, completely ready for use.
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Wooden sleepers. Characteristics, technical requirements
Simply put, sleepers are supports for rails. Their purpose is to receive, elastically process and transmit stress from the rails directly to the ballast prism. In this article we will look at wooden sleepers in detail.
The material used is coniferous tree species. It can be pine, larch, spruce, fir, cedar. The use of birch is allowed for access roads.
The service life of wooden sleepers varies from 7 to 40 years, depending on what kind of wood was used and how intensively they were used; from external conditions. The average service life is about 16 years.
According to GOST, the division occurs into 3 types:
- edged (hewn on all four sides)
- semi-edged (hewn only on three sides)
- unedged (hewn only on top and bottom)
By type, sleepers are divided into 1st and 2nd types.
Impregnation.
When treated with protective agents, wooden sleepers can be either impregnated or unimpregnated. Impregnation methods and materials also have subtypes.
The priority method of impregnation is the “vacuum-pressure-vacuum” method, which is standardized by GOST in Russia.
· Impregnation of wood using the “vacuum-pressure-vacuum” method ensures the deepest penetration of the protective agent and is used for impregnation of wood used in difficult conditions: sleepers, power transmission line supports, piles, bridges, etc. The wood must be dry or dried immediately before impregnation in the same autoclave.
Impregnation of sleepers is carried out with coal oils, creosote, or ZhTK antiseptics for impregnation of railway sleepers.
To impregnate sleepers, manufacturers use a range of equipment: autoclaves, drying chambers, steam generator boilers, etc.
Wooden sleepers consume a lot of wood, but they, unlike reinforced concrete sleepers, soften shaking better.
Wooden sleepers are often used for tram tracks.
Characteristics.
1. The length of the sleepers depends on the track width. In Russia, wooden sleepers with a length of 275, 280 or 300 centimeters are used.
2. Diagram of laying sleepers - this term refers to the number of sleepers per kilometer of railway track. In different countries, this parameter ranges from 1000 to 2200 sleepers. In Russia, according to the standard, there are 3 options: 2000, 1840, 1600 or 1440 sleepers/kilometer. Often a diagram of 1840 pieces/km (46 sleepers per 25 meters) is used on straight sections and 2000 pieces/km on curves.
Main types and sizes
(according to GOST 78-2004).
1. The cross-sectional shape of sleepers is shown in Figures 1-3.
| Picture 1 | Figure 2 | Figure 3 |
2. According to cross-sectional dimensions, sleepers are made of three types, depending on their purpose:
I – for main tracks of the 1st and 2nd classes, as well as for tracks of the 3rd class with a freight load of more than 50 million tons gross km/km per year at train speeds of more than 100 km/h;
II – for main tracks of the 3rd and 4th classes, access tracks with intensive work, receiving and sorting tracks at stations;
3. The dimensions of the sleepers, depending on the type, must correspond to those indicated in Table 1 (see GOST 78-2004).
top face of the sleeper:
The sawn longitudinal surface of the sleeper, which has a smaller width.
bottom face of the sleeper:
The sawn longitudinal surface of the sleeper, which has a large width.
Wane areas of sleepers must be cleared of bark and bast
sleeper side:
Sawed longitudinal side surface of the sleeper.
wane part of the sleeper:
Unsawed areas of the sleeper surface along the top surface and side.
[email protected]: how much does a sleeper weigh?
There are different sleepers) Reinforced concrete, wooden, etc. (sleepers are not rails. The sleepers lie across, but the train runs on the rails, in case you didn’t know))
Type I sleepers (edged, half-edged, unedged) Weight per piece. — ≈ 85 kg Overall dimensions (mm) 180x250x2750 Type II sleepers (edged, half-edged, unedged) Weight per piece. — ≈ 80 kg Overall dimensions (mm) 160x230x2750 Type III sleepers (edged, half-edged, unedged) Weight per piece. — ≈ 80 kg. Overall dimensions (mm) 150x230x2750
By sleepers do you mean supports for rails in the form of beams? Why is such information needed? Well, okay, the question was asked - the answer was received: the weight of a wooden sleeper is 85 kg, the weight of a reinforced concrete sleeper is 270 kg.
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Impregnated wooden sleepers - an easy task
Impregnated wooden sleepers
Over the last century, in the field of railway construction, the technology of laying specially impregnated wooden sleepers into the railway track has been actively used. Wood was not chosen as a raw material by chance, since this material is easy to process and is an affordable raw material for large-scale industrial production.
When laying the first railway tracks, ordinary sleepers were used without any preliminary treatment. Their service life was short, so soon the wood began to be treated with impregnation. The construction of modern railway tracks is carried out from high-quality impregnated wood. Coal oils or various types of products with antiseptic properties are used as an impregnating agent.
The sleeper impregnated with these agents in the overall railway structure represents the main support for the rail laying and is an important element in the upper layer of the track. Its installation is allowed in a variety of climatic zones, on unstable soil bases, and in areas in the permafrost zone. It is not afraid of laying in areas where there is a fairly large cargo flow. By the way, on steep or curved lines with a radius of curvature reaching 350 m or more, laying technology requires the use of exclusively impregnated wooden sleepers.
In Russia, only coniferous trees are used in the production of wooden sleepers. Most of them are pine (70%), less often spruce and other types of coniferous trees are used. The most popular is the pine tree, since it differs from others in its high and even trunk, and the quality of its wood is much more reliable. Fir, spruce and cedar, in comparison with pine, are more often subject to mechanical damage, deformation and cracking. In addition, their wood is considered weak, although it is much more difficult to treat and impregnate it with antiseptics than pine material.
Larch is also a material from which sleepers can be made. True, this wood is also weak and capable of cracking even during the drying period. It also cannot withstand very low temperatures, so it is not suitable for laying tracks in areas with harsh climates. Its use is possible only after additional processing. Birch wood is considered more durable than pine, but is subject to a faster rotting process, and therefore requires deeper and more thorough antiseptic impregnation.
Foreign railways are built using sleepers made from hardwood. Such products are characterized by high resistance to spontaneous loosening and pulling out. The use of sleepers made of hardwood guarantees a service life of about 40 years. Railways laid in tropical areas are built using metal sleepers, since wooden ones are quickly destroyed by termites.
The peculiarities of Russian climatic conditions, on the contrary, do not allow the use of metal sleepers, since climate humidity promotes metal corrosion. Also, such metal structures are a source of increased noise and are dangerous because they have high electrical conductivity.
- Within industrial production, this is the most technologically advanced and cheapest raw material.
- They have high resistance to longitudinal and transverse displacements of the main supports at the level of the ballast layer.
- This is a wear-resistant, durable, strong material that is resistant to physical and climatic influences.
- They are characterized by high elasticity and dielectricity.
The quality of the wood used is determined by the grade (first or second) of the sleepers; defects are unacceptable in their production. We are talking about their possible bending and accidental damage. To prevent cracking of the sleepers during the installation of the railway track, holes for their future fastening are drilled in advance at the factory.
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Application
Wooden sleepers can be used in any laying areas: link tracks with wider gauges, narrow gauge tracks, curves with a small radius (up to 300 meters), on swampy soils, in permafrost zones, on unstable soils, on tracks with high freight traffic.
The use of wooden sleepers is more effective than reinforced concrete sleepers on continuous continuous tracks that are intensive in cargo transportation.
Construction of the foundation
A foundation made of reinforced concrete materials takes on the load from the building pressing on it and distributes it evenly over the entire soil surface. To create a support product, the following materials are required:
- Sleepers.
- Crushed stone and sand.
- Concrete.
- Metal staples, pins.
- Special equipment.
- Mastic, roofing felt.
- Shovels, tape measure, level.
- Pins.
The most popular type of foundation is strip foundation. It involves carrying out excavation work: clearing the area, which includes removing the turf layer and marking the future structure. After preparing the site, they begin digging trenches. Their depth should be 80-100 centimeters. And for a stronger foundation, they dig a width sufficient for three sleepers.
Next comes pouring the concrete. Before starting the procedure, a special formwork is made from the boards, which acts as a form. Reinforcing bars are installed inside this formwork and secured with wire. After the reinforcement layer is ready, it is poured with concrete. Then the entire structure is left alone for two weeks.
After this period, a layer of roofing material is laid on top of the concrete. Reinforced concrete sleepers are placed on it. Next, a reinforcing layer follows throughout the entire volume, and then everything is filled with concrete again.
Features of installation, repair and disposal of reinforced concrete sleepers
The photo shows the operation of a mobile sleeper
Laying railway tracks using reinforced concrete sleepers has a number of characteristic features.
Rails and concrete sleepers, during the construction of railways, are mounted on an initially prepared roadbed based on earth soil, sand and crushed stone backfill. In order to prevent damage to the sleepers during the passage of trains and ensure the safety of the roadbed, special preparation is required, which consists of installing sand strips .
Laying is carried out using mechanized systems that minimize the use of physical labor. As a result, the cost of the installation process is reduced, and in addition, the implementation time for laying the track as a whole is reduced.
As previously mentioned, the service life of reinforced concrete sleepers is limited to 30-60 years. But such durability parameters are only possible if the condition of the tracks is regularly inspected for breakages and partial deformations.
For example, the operational condition of reinforced concrete products is influenced by the condition of the screws securing the lining to the sleeper. If the screw is broken and the problem is not detected in a timely manner, there is a high probability that the lining will hit the concrete as it passes through, causing fatigue stresses in it. (See also the article Hardening of concrete: features.)
If the problem is not eliminated after the screw head comes off, in a relatively short period of time microcracks appear in the thickness of the concrete, which lead to partial or complete destruction of the sleeper.
The photo shows the work of a mechanized complex for recycling solid construction waste
At the end of their service life or due to natural destruction, sleepers must be replaced. At the same time, unusable concrete products must be disposed of.
Since cutting reinforced concrete with diamond wheels for the purpose of grinding seems to be an unreasonably expensive process, processing is carried out using special mechanized complexes. The main working element of the complex is a jaw crusher, which crushes reinforced concrete products to the consistency of medium or small-sized crushed stone. (See also the article Strengthening concrete: how to do it.)
Recycled sleepers can subsequently be used as materials for backfilling pits or for forming embankments.
Dimensions of railway sleepers according to GOST
Geometric characteristics (sizes of sleepers) and classification are given based on the requirements established by the state standard. For example, GOST 78-2004 wooden sleepers for broad gauge railways combines all the characteristics of finished products. For special routes, their own standards have been developed. GOST 22830-77 wooden sleepers for the subway specifies the individual parameters necessary for their operation in these specific conditions. Each standard is consistent with other guidance documents consistent with the operating rules of the various tracks. GOST imposes certain restrictions on wooden sleepers regarding their area of application
Particular attention is paid to the choice of coating that is applied to the surface to improve their technical characteristics
Reinforced concrete sleepers
After the Second World War, reinforced concrete sleepers began to be intensively introduced in many countries, especially in the USSR, East Germany, Germany, France, England, Hungary, Czechoslovakia and Belgium.
Reinforced concrete sleepers have the following advantages: they save wood; do not rot; withstand greater compressive stresses than wood; have greater resistance to movement; have a longer service life. However, the disadvantages include greater rigidity compared to wood, which requires the use of elastic pads
Reinforced concrete sleepers have greater electrical conductivity and require the use of insulating elements; increased fragility requires caution during transportation and tamping, and the large mass creates inconvenience in working with them
In the Russian Federation, preference is given to pre-stressed concrete beam (shaped) sleepers. We began mass laying of standard reinforced concrete sleepers in 1959. Russia ranks first in the world in laying reinforced concrete sleepers.
The design of a modern reinforced concrete sleeper is shown in (Fig. 3). The sleepers are reinforced with periodic wire with a diameter of 3 mm (44 pcs.); the tension force of one wire is 8.1 kN. For the manufacture of sleepers, concrete of grade no lower than 500 is used. The weight of the sleeper is about 265 kg.
Rice. 3 – Reinforced concrete sleepers: a – type ShS-1; b – ShS-ly type; c, d – location of reinforcement
Reinforced concrete sleepers of the ShS-1 and ShS-lu types (erase Fig. 3) are used for fastening KB, and sleepers ShS-2 and ShS-2u are used for unlined fastenings of BP and ZhBR. Sleepers ShS-2 and ShS-2u have the same shape and all dimensions, except for the distances between the holes for embedded bolts, as those for ShS-1 and ShS-ly. The design of the sleeper allows it to be used on rails P50, P65 and P75. The depth of the under-rail grooves for these sleepers is 25 mm.
In addition to string concrete sleepers, in some countries they use block reinforced concrete sleepers with rod reinforcement with a diameter of up to 22 mm. Most often, reinforcement consists of two rods; their stressed state is maintained by nuts screwed onto the ends of the rods. The disadvantages of this design are greater metal consumption than for reinforced concrete sleepers; concentrated arrangement of reinforcement and the associated stronger opening of cracks than with dispersed reinforcement.
Reinforced concrete sleepers make the track more stable, which reduces the cost of its ongoing maintenance. According to V. Ya. Shulga, it is more than 25% cheaper than maintaining a track with wooden sleepers with an average length of 600 m.
The durability of reinforced concrete sleepers for the road network has not yet been determined. Operating experience on the Oktyabrskaya Road (since 1954) and an analysis of their output, carried out by LIIZhT, showed that with a healthy roadbed and ballast layer that meet the technical conditions, the service life depends on the design of the sleeper, the type of rails and fastenings, load intensity, and speed of movement. and loads from wheel pairs on rails. Based on this, a critical tonnage has been established (see table below), after which the reinforced concrete sleepers are affected by defects, and the volume of the annual single shift reaches 30–40 pcs/km.
| Type of fastener and rail | Average load of a wheel pair, kN (tf) | Critical tonnage, million tons gross |
| KB; P65 | 151,9 (15,4) | 1400 |
| KB; P65 | 113,5 (12,6) | 1650 |
| reinforced concrete; P65 | 151,9 (15,4) | 750 |
| reinforced concrete; P65 | 113,5 (12,6) | 840 |
| K2; P65 | 151,9 (15,4) | 1200 |
| K2; P65 | 113,5 (12,6) | 1250 |
| K2; P50 | 149,9 (15,3) | 850 |
During the operation of a track with reinforced concrete sleepers, the rail fastenings wear out greatly. This encourages replacing the rail and sleeper grid, laying the old one on less active lines, and then on station and non-public tracks. Such a system of repeated relaying of track grids with reinforced concrete sleepers will ensure their service life is significantly more than 50 years.
The technical policy assumes a further increase in the range of tracks with reinforced concrete sleepers. In the near future it is planned to increase it to 64–65 thousand km.
Concrete railway sleeper weight
Reinforced concrete sleepers
(according to GOST 10629-71 and TU 32 TsP-517-76)
The sleepers provided for by this standard are designed for the use of rails of types P50, P65, P75 and intermediate rail fastenings of types KB and UB on straight and curved (with a radius of at least 350 m) sections of the track.
The shape, dimensions in millimeters and types of sleepers are given in table. 11 and in Fig. 28.
Table 11
| Types of Sleepers | Types of intermediate rail fastenings | Weight of one sleeper, kg |
| S-56-2 | KB - separate, terminal-bolt with flat lining | |
| S-56-2M | Same | |
| S-56-3 | Reinforced concrete - non-separable, terminal-bolt with spring terminals without lining | |
| S-56-3M | Same |
Notes. 1. In the designation of the sleeper type, the letter C means its abbreviated name (string concrete), the number 56 is the year of design development, numbers 2 and 3 are the serial numbers of design developments, the letter M is a modified sleeper with a wedge-shaped middle part.
2. Sleepers of types S-56-2M and S-56-3M (with a wedge-shaped middle part) are manufactured by agreement of the parties.
The technical conditions apply to timber prestressed reinforced concrete sleepers of type S-73-1 (Fig. 28, e), intended for broad gauge railways.
Sleepers type S-73-1 are designed for the use of rails of types P50, P65, P75 and intermediate rail fastenings of type KB in straight and curved sections of the track (with a radius of at least 350 m).
Sleepers of type S-73-1 are manufactured in molds for sleepers of type S-56-2. The production of type S-73-1 sleepers is allowed only for the period until these forms available at reinforced concrete sleeper factories are worn out.
Sleepers, depending on their quality, are divided into grades I and II.
Note. The supply of grade II sleepers is carried out only with the consent of the consumer for their use on inactive station and access tracks, as well as on industrial railway transport tracks.
Permissible deviations from the design dimensions of sleepers should not exceed the values specified in table. 12.
The slope of the under-rail platforms should be 1/20.
A deviation in the slope value is allowed from 1/19 to 1/21 for grade I sleepers and from 1/19 to 1/22 for grade II sleepers.
The angle of mutual rotation of the under-rail platforms of different ends of the sleeper relative to its longitudinal axis (“sleeper propeller capacity”) should not exceed 0.012 rad.
Sleepers must be made of heavy concrete grade not lower than 500.
Sleepers are delivered to the consumer when the concrete reaches its design compressive strength.
The insert washers must have an anti-corrosion coating.
Note. By agreement with the Ministry of Railways, it is allowed to manufacture sleepers without metal embedded washers with sockets for placing removable plastic liners on embedded bolts.
The following are not allowed in sleepers:
cracks;
exposed reinforcement, with the exception of the ends of stressed reinforcement, which should not protrude beyond the plane of the sleeper ends by more than 5 mm in grade I sleepers and by 15 mm in grade II sleepers;
voids around the wires at the ends of the sleepers;
sealing cavities, beads and voids around the wires at the ends of the sleepers;
chips of working edges and concrete sagging in holes for embedded bolts.
Rice. 28. Types of reinforced concrete sleepers:
a - S-56-2; b - S-56-2M; c - S-56-3; d - S-56-3M; d - C-73-1
Table 12
| Options | Permissible deviations, mm, for sleepers | |||
| according to GOST 10629-71 | according to TU 32 TsP-517-76 | |||
| I grade | II grade | I grade | II grade | |
| Length……………………………………………………………………………………… | ±10 | +10; -15 | ±10 | ±15 |
| Width…………………………………………………………………………………… | ±5 | ±8 | ±5 | ±8 |
| Height……………………………………………………………………………………. | +5; -3 | +10; -3 | +5; -3 | +10; -3 |
| Difference in sleeper heights measured in one cross section…………… | ||||
| Distance “a” between the outer edges of the recesses in the under-rail areas of different ends of the sleeper…………………………………………………………………….. | ±2 | +3; -2 | ±2 | +3; -2 |
| Distance “b” between the edges of the recess and the under-rail area of one end of the sleeper……………………………………………………………………………………… | +2; -1 | +3; -1 | +2; -1 | +3; -1 |
| Distance “c” and “d” between the axes of the holes for the mounting bolts and the outer edge of the recess in the under-rail area of one end of the sleeper……………………………………………………………………………………… ……………….. | ±1 | ±1 | ±1 | ±1 |
| Depth “d” of embedding of embedded washers in concrete…………………………………… | ±3 | ±5 | ±3 | ±5 |
| Transverse dimensions of the hole for the mounting bolt…………………………… | +3; -2 | +5; -2 | +3; -2 | +5; -2 |
| The thickness of the protective layer of concrete above the top row of stressed reinforcement and the vertical distance from each row of wires to the upper edge of the end of the sleeper………………………………………………………………………………………… ….. | ±3 | +10; -3 | +5; -3 | +10; -3 |
On the surfaces of individual sleepers, deviations in terms of appearance are allowed, not exceeding the values indicated in the table. 13.
Table 13
| Types of deviations in terms of appearance | Permissible deviation sizes, mm | ||
| on the top surface of the sleepers | on other sleeper surfaces | ||
| first class | second class | first class | second class |
| Sinks: | |||
| diameter……………………………………………………………………………….. | |||
| depth……………………………………………………………. |
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Reinforced concrete sleepers
Reinforced concrete sleepers after removal from the mold.
In some cases, instead of sleepers, solid block foundations in the form of slabs or frames made of reinforced concrete or metal are used. Since the 1970s, sleepers made of prestressed reinforced concrete have gained popularity in the USSR; their use has been especially successful on continuous-joint tracks.
Reinforced concrete sleepers are reinforced concrete beams of variable cross-section. On such beams there are platforms for installing rails, as well as holes for rail and sleeper fastening bolts (when driving wooden plugs into the holes, crutches and screw connections are also used). Reinforced concrete sleepers are made with pre-tensioned reinforcement. The manufacturing technology of reinforced concrete sleepers is as follows: reinforcement strings are placed in a special mold, tension is applied to them (depending on the purpose of the sleeper, usually 180 atm), the mold is filled with concrete and compacted by vibration. Then the form is disassembled and sent to a steaming chamber, where the concrete hardens, after which the tension from the strings is transferred to the concrete and the form is turned over (turned over). This method of making sleepers gives them elasticity and protects the sleeper from splitting under the rolling stock.
Advantages of reinforced concrete sleepers: practically unlimited service life due to high mechanical strength and resistance to rotting, which makes it possible to reuse sleepers, as well as use them on heavily loaded sections of the track. Disadvantages: insufficient rigidity, high cost and weight, possibility of fatigue failure of concrete.
Recently, anchor connections have been increasingly used to fasten rails and reinforced concrete sleepers [ source not specified 1685 days
A little history
In the photo - wooden sleepers after long-term use
As already mentioned, the history of railways includes several types of supports that are placed under the rails. All solutions had a number of operational shortcomings. For example, the stone was extremely difficult to process and had low shock-absorbing properties.
In addition, despite their apparent strength, these slabs were not the most durable solution, since due to prolonged mechanical exposure they cracked and became partially or completely unusable.
The situation was slightly better with wood products. Such sleepers were tarred to protect against the negative effects of environmental factors. But wood, sooner or later, despite special treatment, rots. And, as a result, the railway tracks require repairs.
Despite the good shock-absorbing properties, wood has one significant drawback - the high price of lumber, even taking into account the ease of their mechanical processing. The situation changed for the better in the second half of the twentieth century when the first reinforced concrete sleepers were developed.
Despite the fact that wooden products are still used on secondary branches, it is reinforced concrete structures that are rightfully considered the most modern and promising solution.
Installation, repair and disposal of sleepers
During the installation of railway tracks using reinforced concrete sleepers, there are some features:
- Before installing supports and rails, preliminary surface preparation is required. In order to maintain the integrity of the sleepers during operation, sand strips are poured onto the top layer of soil.
- For installation, special equipment is used (taking into account how much the structure weighs) to reduce physical costs and reduce the cost of work.
- In order for supports to last longer, it is necessary to perform path diagnostics to detect deformations and defects. Checking fasteners prevents breakdowns.
- As a result of untimely detection of a violation of the integrity of fasteners, cracks and breakage of sleepers (not only partial, but also complete) may occur.
- After the service life has expired, or as a result of destruction of the supports, their disposal is required. In such cases, a jaw crusher is used to crush the products. After processing, they fill holes (small volume) and use them to form embankments.
Sleeper repair involves identifying defects and eliminating them in a timely manner. Cracks, cavities, potholes and chips that arise during operation are repaired.
The following types of repairs exist:
- capital (after preliminary drafting);
- medium (with replacement of defective sleepers);
- lifting (the most common type);
- reconstruction (individual elements are often replaced).
During repairs, a signal sign is placed on this section; train traffic is not stopped. Major repairs are carried out between repairs and consist of replacing sleepers. To perform repair work, track machine stations are used.
Wooden sleepers
Used wooden sleepers The type of wood for sleepers can be different (for example, red maple or eucalyptus), in some countries oak is preferred, and in some, for economic reasons, softwood, mainly pine, although such sleepers are more susceptible to wear.
To prevent rotting, sleepers are impregnated with antiseptics, most often creosote. Wooden sleepers have many advantages: elasticity, ease of processing, high dielectric properties, good adhesion to crushed stone ballast, low sensitivity to temperature fluctuations. The most important property is the ability to widen the rail gauge in curves with a radius of less than 350 m.
The service life of wooden sleepers (depending on the type of wood, external conditions and intensity of use) ranges from seven to forty years. Wooden sleepers in Russia are made primarily from pine, as well as from spruce, fir, and Siberian cedar, although earlier experiments were conducted on making sleepers from oak and larch. The main problem of wooden sleepers is the tendency for them to rot in the places where rails are attached to them, and the problem with their further disposal.
Wooden sleepers are manufactured in accordance with GOST 78-2004.
- Type 1 sleeper, impregnated - used for main tracks
- Sleeper type 2, impregnated - used for access and station tracks
Wooden sleepers are divided into three types:
- edged (hewn on all four sides)
- semi-edged (hewn only on three sides)
- unedged (hewn only on top and bottom)
Previously, a dexel ax (adze) was used to cut sleepers.
Impregnation of wooden sleepers
See also: Sleeper impregnation plant
Impregnation of sleepers is carried out with coal oils, creosote, or ZhTK antiseptics for impregnation of railway sleepers. Currently in Russia, impregnation is carried out using the “vacuum-pressure-vacuum” method; this method is standardized by GOST.
- Sleepers before impregnation
- Autoclave lid
- Impregnated sleepers
- Car loaded with impregnated sleepers
To impregnate sleepers, manufacturers use a range of equipment: autoclaves, drying chambers, steam generator boilers, etc.
Impregnation of wood using the “vacuum-pressure-vacuum” method ensures the deepest penetration of the protective agent and is used for impregnation of wood used in difficult conditions: sleepers, power transmission line supports, piles, bridges, etc. The wood must be dry or dried immediately before impregnation, including or autoclave.
Types
Taking into account the length, width of products, resistance to cracking, the following types exist:
- 1st grade sleepers;
- sleepers of 2 grades (less stringent requirements are imposed on geometric dimensions, the degree of resistance to cracking is low).
Products of grade 2 are used for laying on access, station and non-active tracks. Their delivery is carried out only with the consent of the consumer.
Based on the type of rail fastening, products are divided into types:
- Ш-1 (separate clamp-and-bolt connection, attached to the support with a bolt and gasket);
- Ш-2 (indivisible mount);
- Sh-3 (similar to Sh-2 supports, differ in the method of fastening).
Reinforced concrete products differ in class, type of reinforcement used, and the presence of electrical insulation (non-insulated or insulated). The requirements for the parameters of reinforced concrete sleepers are strict.
Standard reinforced concrete sleepers have the following dimensions (W-1 - dimensions LxWxH in mm): 2700x300x230, 250 kg weight.
Depending on the features of use and installation, reinforced concrete rail supports are:
- pavements (laid on bridges);
- shuttle (for bridges and tunnels);
- intended for curved sections (with a radius of less than 350°);
- transformer (differ in rectangular cross-section along the length);
- for turnouts;
- for children's railways (wheel width 750 mm, rails R-43);
- half sleepers (for tracks along which overhead cranes move).
Theoretical weight of VSP materials | LLC ZhD Invest
| Name | Price with VAT | |
| Railway bolts | ||
| Mortgage bolt M22x175 | 0.635 kg | |
| Mounting bolt M22x175 assembled | 1.011 kg | |
| Terminal bolt M22x75 | 0.345 kg | |
| Terminal bolt M22x75 assembled | 1.204 kg | |
| Terminal bolt M22x75 with nut | 0.459 kg | |
| Butt bolt M18x88 with nut (R-24) | 0.262 kg | |
| Butt bolt M22x135 with nut (R-43) | 0.61 kg | |
| Butt bolt M24x150 assembled (P-50) | 0.806 kg | |
| Butt bolt M27x160 assembled | 1.128 kg | |
| Railway nuts | ||
| Nut M22 | 0.126 kg | |
| Nut M24 (butt) | 0.153 kg | |
| Nut M27 (butt) | 0.22 kg | |
| PC terminal | ||
| Intermediate terminal PC | 0.625 kg | |
| Railway crutches | ||
| Travel crutch 14x14x130 | 0.18kg | |
| Travel crutch 16x16x165 | 0.38kg | |
| Railway pads | ||
| Overlay 1Р-43 | 16.01 kg | |
| Overlay 1Р-50 | 18.77 kg | |
| Overlay 1Р65 | 29.5kg | |
| Overlay 2Р-65 | 23.78 kg | |
| Transfer beam | ||
| Railway chocks | ||
| Lining D-43 | 5.26 kg | |
| Lining D-50 | 6.2 kg | |
| Lining D-65 | 7.66 kg | |
| Lining DN6-65 | 8.44 kg | |
| Lining KB-50 | 6.85kg | |
| Lining KB-65 | 6.85 kg | |
| Lining KD-65 | 9.6kg | |
| Lining SD-50 | 6.5 kg | |
| Lining SD-65 | 6.97 kg | |
| Anti-theft | ||
| Anti-theft P-50 | 1.22kg | |
| Anti-theft P-65 | 1.36kg | |
| Rail insulation | ||
| Rails | ||
| Rails R-18 | 17.91kg/m | |
| Rails R-24 | 24.9kg/m | |
| Rails R-43 | 44.65kg/m | |
| Rails R-50 | 51.67kg/m | |
| Rails R-65 | 64.88kg/m | |
| ARS fastenings | ||
| Turnouts | ||
| Railway washers | ||
| Double-turn washer M22 | 0.12kg | |
| Single-turn washer M24 (R-50) | 0.068 kg | |
| Single-turn washer M27 (R-65) | 0.093kg | |
| Flat washer-bracket TsP-138 | 0.09 kg | |
| Wooden sleepers | ||
| Reinforced concrete sleepers | ||
| Railway screws | ||
| Travel screw M24x170 | 0.56kg | |
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Production technology
Figure 3. Production of reinforced concrete sleepers
Depending on how much the sleeper will weigh and how much work is expected, a certain technology for manufacturing the product is selected. There are only 4 of them:
| Technology | Description |
| Carousel | A special feature of the method is the delay in removing the mold. The concrete mixture is poured into the prepared form. The solution must be well compacted so that no air bubbles remain in it. In this work, special forms of 6 elements are used. I remove them only after the sleepers have reached their maximum strength parameters. In order for the reinforcement to have good adhesion to the concrete mixture, it is necessary to ensure tension in the steel rods using special tension mechanisms |
| Linear | It involves the use of a conveyor on which forms are installed. Its length sometimes reaches 100 m. At the ends of the molds there are special devices with the help of which pre-stress is transferred to the steel rods. As soon as the concrete mixture hardens well, force is applied to it |
| Removal of the mold followed by transfer of stress | In this case, the forms are installed in templates, the location of the reinforcement in which is precisely defined. After pouring the concrete solution, it is thoroughly compacted by vibration. While the mixture is hardening, metal rods are inserted into it and pressure is applied to it. After hardening, the mold is dismantled and the template is removed. The advantage of the technology is continuity and the presence of a small number of forms |
| Dismantling the pre-stressed mold | This method is similar to the previous one, but frames are used instead of rods |
The choice of technology for the production of concrete sleepers depends on what technical characteristics are required.
Main characteristics
Scheme and dimensions of reinforced concrete sleepers Ш1
The instructions for using reinforced concrete sleepers in the post-Soviet space have been tested for more than 40 years.
In accordance with GOST 23009, modern concrete sleepers are rail supports made in the form of beams with variable size and cross-sectional shape. The product is reinforced with reinforcing wire with a cross-sectional diameter of 3-6 mm, depending on the modification.
During operation, the product is laid on top of the ballast layer. In relation to conventional tracks, large-sized crushed stone is used as a ballast embankment, and when arranging the subway, a slab-type concrete base is used.
Schematic representation of reinforced concrete products type Sh1
Products made of prestressed reinforced concrete, used as under-rail supports, are the optimal solution for both continuous and other categories of tracks.
The relevance of these designs is explained by a number of technical and operational advantages, including:
- long service life;
- optimal indicators of resistance to the negative effects of environmental factors;
- resistance to mechanical loads;
- non-susceptibility to rotting throughout the entire service life;
- Possibility of installation on tracks with any level of congestion;
- relatively low price;
- minimum costs required for operational maintenance;
- ease of installation and installation, in comparison with wooden analogues;
- absolute identity of standard sizes, shapes and weights, which guarantees ease of transportation and shipment.
In the photo - tongs for carrying sleepers
Are there any disadvantages that could negatively affect the use of these concrete products?
There are few such disadvantages:
- Firstly, there is the possibility of fatigue failure of the concrete structure and, as a consequence, the need for periodic inspection of the tracks.
- Secondly, the weight of the reinforced concrete sleeper (270 kg) makes it impossible to install it yourself without the use of special equipment. Therefore, unlike wooden analogues, concrete structures are installed using specialized sleeper layers.
Scope and conditions of application
Schematic representation of reinforced concrete sleepers type Ш3 and Ш3Д
Sleepers made using prestressed concrete are widely used in the construction of railway transport links around the world.
Considering the variety of climatic conditions in which these products are operated, as well as the varying degrees of mechanical loads, increased demands are placed on the production of sleepers, as well as on the quality of the finished product. As a result, depending on the favorable conditions of use, these reinforced concrete products can be used in for 30-60 years.
Reinforced concrete sleepers for laying travel paths for rail cranes
The widespread replacement of conventional wooden supports with reinforced concrete analogues is explained not only by strength and durability, but also by short production times.
For example, the production of ready-to-install concrete products requires only a few hours, which is very convenient when we are talking about the construction of a large branch and the constant supply of large volumes of building materials is required. Again, concrete products can be repaired and adapted for operational needs using diamond drilling of holes in concrete.
Important: Sleepers manufactured by domestic manufacturers using prestressed reinforced concrete in accordance with GOST requirements are superior to their foreign counterparts in terms of load-bearing capacity and material consumption.
Requirements for railway reinforced concrete sleepers
Installation of rails and reinforced concrete sleepers before laying on the embankment
As already mentioned, the operating conditions in which sleepers are used place high demands on the production technology of these reinforced concrete products and, in particular, on the production technology of prestressed reinforced concrete.
The following requirements apply to the material and the finished product:
- Strength sufficient to transfer the prestressing force within a few hours (the time is set in accordance with the modification of the reinforced concrete products) at the end of the production process.
- The maximum possible degree of homogeneity of the consistency of freshly prepared concrete.
- The accuracy of dimensions and shapes is an order of magnitude higher than similar requirements for other categories of commonly used reinforced concrete and prestressed reinforced concrete structures. These requirements mean tolerances on the angle of inclination, length and width of individual structural elements. The dimensions in areas adjacent to the rails are especially strictly controlled.
Important: In Western Europe, the technical requirements that determine the quality of the source material used in the manufacture of reinforced concrete sleepers are regulated by the EN 13230 standard. The strength class of the source material in domestic production is determined by the higher requirements given in GOST 26633.
Manufacturing technologies
Forms for pouring concrete with rods to transfer prestress
Regardless of whether the foundation is planned to be made of reinforced concrete sleepers or the reinforced concrete products will be used for their intended purpose, the strength of these structural elements will be guaranteed. The performance qualities of finished products are ensured by production technologies.
Despite the fact that many sleeper manufacturing methods have been tested over the course of more than fifty years, today the four most common production technologies that meet the requirements of international standards are widely used.
- Carousel technology with delayed mold removal. The peculiarity of this technological process is that the finished mixture is poured into molds and compacted. Removal of the product from the mold is carried out only after achieving optimal strength indicators sufficient to apply a prestressing force. During the manufacturing process, specialized collapsible cassette molds are used, which can accommodate up to six units of the product. Through the use of special tension mechanisms, pre-stressing of the reinforcing bars is ensured, which is subsequently transferred to the concrete and ensures optimal adhesion to it. Once the reinforced concrete sleeper is ready, the mold can be dismantled and immediately used for the next production cycle. The name of the method is explained by the type of production process and the design features of the molds used, which are located on a carousel-type transport system. This method has become widespread in Western European countries and is considered the most promising and technologically advanced.
- Linear technology. No matter whether the reinforced concrete half sleeper for rail cranes or a full-size product is manufactured, the production process can be realized based on linear technology. The production process uses a conveyor with a series of molds arranged in series. The total length of the chain is usually at least 100 meters. At the ends of the molds, special devices are used that not only close the mold, but also transfer pre-stress to the reinforcing bars. As the mixture dries, the force is transferred to the concrete.
- Technology of mold removal with subsequent tension.
In the photo - a modern line for the production of sleepers of Western European standard
In this case, templates are inserted into the forms, which will determine the location of the metal reinforcement. The concrete is then poured into the molds and compacted.
As it hardens, metal pins are inserted into the thickness of the mixture and applied mechanical force. After a short period of time, the mold is dismantled and the templates are removed. The advantage of this method is that the process is essentially continuous, and therefore a limited number of forms are needed to obtain the desired result.
- Technology of mold removal with pre-stressing. In this case, the form is removed as quickly as in the previous method. The only significant difference between this technological process is that the tensile force is transmitted to the product not through pins, but through frames.
