Author: Site Editor Publish Time: 2024-01-11 Origin: Site
Train wheelset is an important part of railway rolling stock, mainly composed of wheels and axles. Wheel is the part of the train and rail contact, bear the weight of the vehicle and the role of guidance; axle is connected to the wheels and other parts of the vehicle bridge, passing the traction and braking force. The performance of train wheelset directly affects the safety and smoothness of train operation, so its maintenance and overhaul is very important.
Firstly, the weight of the wheelset has a direct impact on the operational efficiency and safety of the train. Heavier wheelsets provide more traction, allowing the train to climb and accelerate more easily. However, a heavy wheelset can also lead to increased energy consumption, longer braking distances and may even exceed the capacity of the line. Conversely, lighter wheelsets may have higher efficiency and lower energy consumption when running on flat and straight lines, but slippage or wheelset idling may occur when climbing or braking, affecting the operational safety of the train.
Secondly, weight also affects the quality and efficiency of the whole transport process. If the wheelsets are too heavy, it may lead to excessive wear and tear of the lines and bridges and shorten their service life. This will not only increase the maintenance cost, but may also affect the operational safety of the train. And if the wheelset is too light, it may lead to insufficient traction and affect the transport efficiency of the train.
The weight of the wheel and wheel size and material related, the following table lists the different types of trains and buses train wheel weight, from the table can be seen, the weight of a wheel in the range of about 300kg-400kg.
wheel model | roll over circle outer diameter D(mm) | Rims Inside Inside Diameter D1(mm) | Rims outer side Inner Diameter D2(mm) | wheel Hole diameter （thick）d0 | wheel Hole diameter （vitality）d1 | Wheel outer diameter D3 | Wheel length L | Wheel rim width H | Distance between wheel rims F | Spoke Thickness（thinnest point） AS | theoretical weight (Kg) | material |
| HEZD | 840 | 740 | 740 | 198 | 206 | 282±4 | 178±3 | 135+5 | 68+2 | 22 | 325 | ZL-B |
| HDZD | 840 | 740 | 740 | 186 | 194 | 263±4 | 178±3 | 135+5 | 68+2 | 21 | 315 | ZL-B |
| HDZB | 840 | 740 | 740 | 186 | 94 | 260+6 | 178±3 | 135+5 | 68+2 | 23 | 330 | ZL-B |
| HDZC | 840 | 740 | 740 | 186 | 194 | 260+6 | 178±3 | 135+5 | 68+2 | 20 | 310 | ZL-B |
| HEZB | 840 | 740 | 740。 | 198 | 206 | 278+10 | 178±3 | 135+5 | 68+2 | 21 | 322 | ZL-B |
| HDZA | 840 | 710 | 710 | 186 | 194 | 260+6 | 178±3 | 135+5 | 68+2 | 25 | 371 | ZL-B |
| HDZ | 840 | 710 | 710 | 186 198 | 194 206 | 289+5 | 178±3 | 135+5 | 68+2 | 25 | 385 | ZL-B |
The weight of train axle is also related to the size and material of the axle, the table lists out the weight of different sizes of train axles, from the table, the weight of the axle range is relatively large, about 200kg-500kg.
axle model | size(mm) | weight (kg) | |||||||||
| d1 | d2 | d4 | d5 | L1 | (L2) | L3 | (l1) | L2 | L4 | ||
| RE2B | 150 | 180 | 210 | 184 | 2181 | 1981 | 1761±1 | 210 | 83 | 266.5 | 451 |
| RE2A | 150 | 180 | 210 | 184 | 2191 | 1981 | 1731±1 | 230 | 48 | 229 | 451 |
| RE2 | 150 | 180 | 206 | 184 | 2166 | 1956 | 1686+1 | 240 | 68 | 251.5 | 440 |
| RD2 | 130 | 165 | 194 | 174 | 2146 | 1956 | 1706±1 | 220 | 53 | 239 | 380 |
| RD2Y | 130 | 165 | 194 | 174 | 2146 | 1956 | 1706±1 | 220 | 53 | 239 | 380 |
| RB2 | 100 | 127 | 155 | 138 | 2062 | 1905 | 1688±1 | 187 | 44 | 230 | 232 |
| RD3 | 130 | 165 | 194 | 174 | 2146 | 1956 | 1756±0.5 | 195 | 78 | 264 | 383 |
As can be seen from the above, the weight of a conventional train wheel in 300kg-400kg, the weight of conventional train axles in 200kg-500kg, the total weight of the wheelset is equal to the weight of the two wheels plus the weight of an axle, i.e., a train wheelset weight is about 800kg-1300kg, more detailed data need to be based on the drawings for calculation.
High-carbon steel and alloy steel in the weight of train wheels on the difference mainly depends on their density and weight. High-carbon steel is a high carbon content of steel, has a high density and weight, so the use of high-carbon steel manufacturing train wheel is relatively heavy. Alloy steels, on the other hand, are carbon steels to which alloying elements have been added, and these alloying elements can change the density and weight of the steel. Some alloying elements increase the density and weight of the steel while others decrease it. As a result, the weight of a train wheelset made from alloy steel may be higher or lower than a wheelset made from high carbon steel, depending on the alloying elements added and their content.
The quenching process has an effect on the weight of train wheelsets, mainly in the following aspects:
Density change: quenching is a heat treatment process, through rapid cooling to make the metal to achieve high hardness and high wear resistance. In the quenching process, the arrangement of atoms or molecules within the metal will change, resulting in a change in density. Typically, there is a slight increase in the density of the quenched metal, so the quenching process may result in a slight increase in the weight of the train wheelset.
Dimensional changes: During the quenching process, the metal may shrink or expand, resulting in changes in its dimensions. If the dimensions of the metal decrease after quenching, then the weight of the whole product may decrease accordingly. Conversely, if the dimensions increase, the weight may increase. Thus, the quenching process has an effect on both the size and weight of train wheelsets.
Surface treatments: The hardening process can also be used in combination with other surface treatment techniques, such as painting and plating. These surface treatments may increase the weight of the train wheelset as well as change its appearance and performance. Therefore, the effect of surface treatments on the weight of train wheelsets also needs to be considered.
When using wheelsets at high altitude, the weight of the wheelset may change due to the decrease in air pressure and oxygen concentration. Specifically, as the altitude increases, the atmospheric pressure and oxygen concentration gradually decrease, resulting in a corresponding decrease in the density and weight of metal materials. Therefore, the weight of the wheelset may decrease slightly when it is used at high altitude.
The weight of the wheelset directly affects the traction and braking performance of the train. A heavier wheel will increase the inertia and traction resistance of the train, making it more difficult to accelerate and decelerate the train. Therefore, when designing a train, it is necessary to choose the weight of the wheelset reasonably, in order to balance the needs of traction and braking performance.
Energy consumption: The weight of train wheelsets has a greater impact on energy consumption. A heavier wheelset will increase the traction resistance and inertia of the train, making the train consume more energy when accelerating and decelerating. Therefore, under the premise of ensuring safety and performance, appropriately reducing the weight of the wheelset can reduce the energy consumption of the train and improve operational efficiency.
Wear: The weight of a wheelset also affects its contact stress with the track, which in turn affects the degree of wear. Heavier wheelsets will generate greater contact stresses when in contact with the track, accelerating the wear of the track and the wheelset. Therefore, when selecting a wheelset, it is necessary to weigh the need for weight against the need for wear resistance to ensure the service life and safety of the wheelset.
Smoothness of operation: The weight of the wheelset affects the smoothness of train operation. A heavier wheelset generates a relatively large amount of shock and vibration when it comes into contact with the track, which can lead to unstable train operation, affecting the comfort of passengers and the safety of goods. Lighter wheelsets can reduce shock and vibration and improve smoothness of operation, but too light wheelsets may also cause increased friction and vibration between the wheels and rails, affecting performance and safety. Therefore, when choosing the weight of a wheelset, it is important to balance the needs of all parties involved.
Vibration: The weight of a train wheelset can also affect its vibration characteristics. Heavier wheelsets may produce more vibration, especially at high speeds or when travelling through curves. This vibration may lead to increased wear and tear between the wheels and rails, affecting the service life of the wheels and rails.
The new aluminium alloy material has obvious advantages in high-speed train wheelsets. Firstly, it significantly reduces the weight of the train, which improves the operation efficiency and energy saving effect. Secondly, aluminium alloy material has excellent corrosion resistance and mechanical properties, which can improve the stability and service life of the train. In addition, aluminium alloys are relatively easy to process and recycle, which helps to reduce maintenance costs.
However, the performance of aluminium alloy materials under complex environmental and loading conditions needs to be considered in practical applications, and continuous monitoring and evaluation should be carried out to ensure the safety performance of trains.
Lightweighting can be achieved by improving the structure of the wheelset and reducing unnecessary components and materials. Examples include the use of hollow axles, optimising the structure of bearings and braking devices.
Energy saving and emission reduction: with the increasing attention to environmental protection, energy saving and emission reduction has become an important development direction of the railway transport industry. Optimising the weight of train wheelsets can reduce the energy consumption and carbon emission when the vehicle is running, thus contributing to the cause of environmental protection.
Improve transport efficiency: Lighter wheelset weight can make the train more flexible in operation, reduce the power loss caused by excessive wheelset weight, and thus improve transport efficiency.
Reduced wear and tear: Reducing the weight of the wheelset reduces wear and tear on the track, prolonging the life of the track and reducing maintenance costs.
Improve safety: Reducing the weight of the wheelset can reduce the bumps and vibration of the vehicle in the process of running, and improve the stability and safety of the train.
Promote economic development: optimising the weight of train wheelsets can improve the competitiveness of railway transport and promote the development of railway transport industry, thus driving the development of the whole economy.
