Rail
Railway equipment is an important equipment of the railway, and the rail is the main symbol of railway equipment.
A—Rail height, B—Bottom width, C—Head width, D—Waist thickness
(1) Classification. Rails can be divided into two types: heavy rail and light rail in kilograms per meter:
(1) Heavy rail. According to the steel used steel type, it is divided into: ordinary manganese-containing steel rail, copper-containing carbon steel rail, high-silicon copper-containing steel rail, copper rail, manganese rail, silicon rail, etc. There are three main types: 38, 43 and 50kg. In addition, there are 45kg rails for a few lines, and 60kg rails are planned for high-volume and high-speed lines. GB2585-81 stipulates the technical conditions of China's 38~50kg/m steel rail.
(2) Light rail. There are mainly 9, 12, 15, 22, 30 and other different track types.
(2) Manufacturing and use. The rail is rolled from carbon calm steel smelted by open-hearth furnace and oxygen converter. Its purpose is to withstand the operating pressure and shock load of rolling stock.
(3) Production plant and importing country. The steel rails currently used in China are mainly produced by some domestic steel mills, such as Angang and Wuhan Iron and Steel. In addition, due to the large dosage, it is still necessary to import some rails and rail accessories that are judged according to the physical and chemical properties required by China's technical standards and according to relevant foreign standards and methods. Import producing countries include Japan, Germany, France, the United Kingdom, Russia, Australia, etc.
2. Size specifications
The length and other geometric dimensions and tolerances of the rail are specified by the corresponding standards for light and heavy rails in "8".
3. Appearance quality
(1) The rolled rail should be straight and should not have significant bending and torsion. For the local bending and torsion of light and heavy rails and their corrective deformation, the inclination of the track end face, etc., shall not exceed the standard provisions.
(2) The surface of the rail should be clean and smooth, and there should be no cracks, scars, scratches and other defects; Its end face must not have shrinkage marks and interlayers. The allowable defects on the overall surface of light and heavy railways and the degree of their geometry shall not exceed the provisions of the standard.
Rail braces
In the track components, in order to effectively resist the transverse forces of the wheel and rail, the components installed on the outside of the rail. It is generally installed on the outside of the outer strand rail of the small-radius curved track to prevent the train from passing through the curve, and the excessive lateral force causes the lateral displacement of the track to be too large, and even cause the rail to overturn. Generally, rail braces are used for wooden sleeper tracks. In most turnout tip rail parts, rail braces are also installed on the outside of the basic rail to improve the lateral rigidity of the rail, and the shape of rail braces is also more.
Types of rail braces:
Adjustable rail brace: an adjustable rail brace is composed of adjustable rail brace body, adjustable rail brace rack base, rail brace washer and nylon rail brace base gasket, which is characterized by: the rack slope of the adjustable rail brace rack base is 12 ° ~ 15 °, and the tooth pitch of the serrations is 10-15mm.
Elastic rail brace: The appearance design rail brace is mainly set on the non-working side side of the turnout switch, guide curve rail and guard rail, and the basic rail of the double switch switch is also set with rail brace. The rail brace is set in the turnout mainly to prevent the rail from overturning and gauge expansion, and to ensure the stability of the rail.
Anti-crawl rail brace: it includes basic rail, cushion plate, fork pillow bolt, fork pillow, the basic rail rail body is spaced along the long interval with holes, the anti-climbing rail brace is connected to the basic rail by bolts and anti-loose nuts, the two sides of the anti-climbing rail brace are stuck on both sides of the cushion plate, and the cushion plate is connected to the fork pillow through the fork pillow bolt. Advantages: It can not only effectively limit the longitudinal position of the basic rail, prevent the relative displacement of the basic rail and turnout pillow, but also ensure the stability of the switch structure and the high smoothness of the turnout.
Anti-climber
When the train is running, the longitudinal force acting on the rail is often generated, so that the rail moves longitudinally, and sometimes even drives the sleepers to move together. This longitudinal movement is called crawling. Crawling generally occurs on the main line of the interval of the double-track railway, the direction of the heavy car on the single-track railway, on the long downhill and within the braking range when entering the station.
Line crawling often causes uneven rail seams, skewed sleepers and other phenomena, which is very destructive to the line, and even causes a small rail runway, endangering driving safety. Therefore, effective measures must be taken to prevent crawling, usually using anti-climbing and anti-climbing braces to prevent line crawling.
The pin-piercing anti-climber consists of a piercing pin of a rail card with a baffle. When installing, one side of the rail card is clamped to the bottom of the rail, and the other side is wedged into the threading pin, so that the entire anti-climber firmly jams the bottom of the rail. In this way, when the rail is subjected to longitudinal resistance, the sleeper and the shearing prevent the rail from crawling because the baffle of the rail card is close to the sleeper. In order to give full play to the role of the anti-climbing device, anti-climbing braces are usually installed between the sleepers, and 3~5 sleepers are linked to jointly resist the crawling of the rail.
Sleeper
It is necessary to support the rail, maintain the position of the rail, and transfer the huge pressure transmitted by the rail to the track bed. It must have a certain degree of flexibility and elasticity, hard or soft. As the train passes, it can be deformed appropriately to cushion the pressure, but it must be restored as much as possible after the train passes. Sleepers include wooden sleepers and concrete sleepers.
1. Wood sleeper is a sleeper made of wood. Also known as sleepers, antiseptic wooden sleepers, also called oil-filled sleepers. Wooden pillows must be made of tough and resilient wood. Wooden sleepers can be divided into ordinary wooden pillows, fork pillows, and bridge sleepers according to their use. The standard length of ordinary wooden sleepers is 2 .5 m, and their cross-sectional shapes are divided into two categories, I and II, which are used on different grades of lines. The turnout pillow used on the turnout is wider than the wooden pillow, the length is from 2600mm to 4 800mm, a total of 12 types, each length difference of 20mm, when used according to the actual width of the turnout group selection. Used for bridge sleepers, the cross-sectional dimensions of which vary depending on the size of the center spacing of the main beam (or stringer). Wooden pillows have the advantages of good elasticity, easy processing and easy to use. Since the beginning of the railway, wooden sleepers have been the main type of sleeper. However, due to the use of materials, the elasticity, strength and durability of the wooden sleeper are not uniform enough, which will increase the wheel-rail dynamic effect, and a large amount of high-quality wood is used. The service life of wooden sleepers is short, and there are many reasons for their failure, mainly decay, mechanical wear and cracking. Because wooden pillows are perishable, they are treated with antiseptic treatment before going on the road. Wooden pillows that have not been embalmed are called plain pillows. China's wood resources are relatively scarce and expensive, and have been gradually replaced by concrete pillows on the main trunk lines.
2. Concrete sleepers, including threaded road nail structure, reinforcement, fasteners and gauge adjustment, height adjustment, are characterized in: shoulder concrete heightening, gauge baffle thickening, rubber pad thickening, concrete sleepers arranged according to vertical staggered arrangement with spiral rib steel bars, shear ribs at the end of the shoulder position, baffle seat and concrete sleeper shoulder grooves at both ends of the groove, gauge baffle and baffle seat closely.
3, railway accessories sleeper concrete pillow, also known as concrete pillow, after the Second World War, concrete pillow began to be used in large quantities, the advantages of concrete pillow are good stability, long service life, maintenance and repair cost saving; The disadvantages of concrete pillows are large weight, poor elasticity and insulation performance, and buffer insulation cushions must be provided at the bottom of the track.
Connect parts
The connecting parts are divided into two categories, and the parts that connect the ends of the two rails are called joint connection parts; The part that connects the rail and the sleeper is called the intermediate connection part, that is, the fastener. The joint connection parts allow the wheels to roll smoothly through the rail joints and keep the front and rear rails working in harmony. The fastener connects the rail and sleeper to form a track frame, so that the two rails maintain the correct relative position; The fasteners provide sufficient pressure to prevent the rail from overturning and prevent the longitudinal movement of the rail.
Road bed
It usually refers to the ballast (ballast) cushion laid on the subgrade surface under the sleeper. The main function is to support the sleeper, and evenly distribute the huge load from the upper part of the sleeper to the subgrade surface, which greatly reduces the deformation of the subgrade. Ballast is a small block of granite with a diameter of 20~70mm, there are gaps and friction between blocks, so that the track has a certain elasticity, this elasticity can not only absorb the shock and vibration of the rolling stock, so that the train runs relatively smoothly, but also greatly improves the working conditions of the locomotive and rails, sleepers and other components, and prolongs the service life. Once the elasticity of the ballast is lost, the load on the reinforced concrete sleeper is increased by 50~80% compared with the normal state.
Turnout
A turnout is a kind of line connection device that enables rolling stock to transfer from one strand to another, usually laid in large quantities at stations and marshalling stations. With turnouts, the passing capacity of the line can be fully utilized. Even if it is a single-track railway, you can split the train by laying a turnout and building a fork line larger than the length of the train.