Railway sleeper is a part of railway track, which is usually laid between two rails to keep the correct position of steel rail.
Free from decay and are not attacked by vermins; Connection between rail and sleeper is … In the last years, plastic railway sleepers have made their introduction.
Hence, the sleeper withstand well against high external pressure.Steel sleepers are more often used because of stronger than wood and economical than concrete. If the bending stiffness is much lower, localizing the contact area can increase the stresses. Sleepers are normally spaced at 650 mm (25 ins) to 760 mm (30 ins) intervals, depending on the particular railway's standard requirements. 2) Regulations 2003 came into force which prevents the use and re-use of creosoted sleepers other In the treatment process these juices are removed as much as possible and cells are filled with some preserving solutions may be an oil or some salt solution.
According to different applications, wood sleepers can be divided into three types: ordinary wooden sleeper, turnout sleeper and bridge sleeper. There are also now various environmental concerns regarding the use and disposal of chemically-impregnated traditional sleepers. Functional requirements for rail sleepers, that exist independently from the materials used, should be developed.To determine the necessary sleeper properties, the first priority is to determine the required system stiffness. Tropical hardwood can do without creosotes, but its environmental implications and availability do not make it a viable alternative for large scale application. These are still widely using in some western countries. What is the Process Flow Sheet Diagram of Precast RCC Railway Sleepers Manufacturing project?
Steel sleepers. Hence reinforcement is provided in the concrete wherever tensile stress is expected. Sleeper compressive flexibility on a bridge should be much higher than in track to compensate for the missing flexibility of the ballast. Wooden sleepers are therefore still being used in a lot of applications where concrete is too rigid a material.
We have a current capacity of 80,000 sleepers per annum with the flexibility to expand. The stress in the ballast is best kept below 0,5 MPa to prevent this (Esveld, 2007). For determination of the maximum track stiffness according to Riessberger, not the maximum permitted loading is of interest, but a mean expected loading. OneSteel Whyalla Steelworks manufacture steel sleepers The life of untreated wooden sleepers is thus very less. Pot type sleepers are not suitable for curves sharper than 4 degrees. Taking as an estimate 2/3 of the maximum allowed loading and fAs derived by Zimmermann in 1888, we can calculate the relation between the wheel load Q and the load F that is applied on the sleeper (Esveld, 2007) with Equation 2 in Table 2. However, when not treated with creosotes, the lifespan of a wooden sleeper is quite limited, giving high replacement costs. For this reason, wood sleepers are widely used throughout the world. The steel sleepers and fastening assembly tie the rails together, maintaining gauge and rail position whilst resisting lateral and longitudinal movement of the rail. Plastic is however a material with other characteristics than wood or concrete. 26. 2) Regulations 2003 came into force which prevents the use and re-use of creosoted sleepers other While concrete sleepers still have many disadvantages like heavy weight, difficult to transport and environment limits. These sleepers generally rests on ballast and is also called as ties in some regions. The highest contact stress between sleeper and ballast will occur under the rail seat, as can be seen in Figure 11. Whatever you do, sleeper properties can never compensate the variations in bedding modulus. At the same time it describes the current problem in developing plastic sleepers. Railway sleeper is also known as railroad tie or crosstie. The sleeper length has a lot of influence: a sleeper length of 2600 mm gives a more stable railhead than a 2400 mm sleeper. Strength analyses of the sleeper can be done according to the calculation model of Figure 15. These materials have a bending stiffness and a thermal expansion coefficient, that makes them unsuitable to be used as is. They are molded in trough shape and placed on ballast in inversed trough shape.Cast iron sleepers are widely used in the world especially in Indian railways. Since plastic sleepers have a comparable system and contact stiffness as wood, degradation of ballast is also expected to be comparable. Dusseldorf: University of Graz. Concrete is however a stiff material, consequently dynamic forces and vibrations are high, which causes, for example, high wear and degradation to the ballast.
Sleepers with a higher flexibility should therefore be used in a switch to create a continuous track stiffness.The basic thought on sleeper bending stiffness seems to be that the higher the sleeper bending stiffness is, the better the sleeper performance. We just got carried away." Since concrete sleepers are stiffer than wooden sleepers, it can be concluded that a high system stiffness and high contact stiffness are the main contributors to ballast wear. It should not be regarded as a substitute for wood or concrete, but its unique characteristics should be made use of.To make a suitable plastic railway sleeper, the material choice to get to a pricewise compatible sleeper should be one of the bulk plastics, most likely Polyethylene or Polypropylene. CST 9 type sleepers more famous in Indian railways.Composite sleepers are modern type sleepers which are made from waste plastic and rubber. They are available in 2 types, pot type sleepers and plate type sleepers. Within the European union creosotes will soon be banned, which are now used to give the wooden sleepers an acceptable life span.