The importance of the correct wheel load and what factors are influencing it chin

The correct wheel load 正确的车轮载荷 Importance, influences and methods for adjustment 重要性，影响和调整方法

Page 1 of 13

Introduction 介绍 Regardless of a freight, a highspeed, a normal speed or a mass transit train – nobody wishes for an accident caused through derailing. In the event of an incident, due to a faulty bogie, the operation of a complete metro line can be interrupted followed by immediate negative news headlines in the press and social media. A worldwide topic is the reduction of wheel wearing in order to minimize the life cycle costs of a train. 无论货车，高铁，常速或轨道交通列车，没有人愿意看到脱轨造成的事故。 如果事故是由转 向架有故障而导致的，那么整个地铁线路的运行可能会被中断，紧随其后的是新闻界和社交媒 体的消极新闻头条。 减少车轮磨损是一个全球性的话题，以最大限度地降低火车的生命周期 成本。 An important factor to reduce the mentioned problems and risks is to adjust and control the correct wheel load. 减少上述问题和风险的一个重要因素是调整和控制正确的车轮载荷。 The importance of the wheel load 车轮载荷的重要性 The safety against derailing depends on two important forces: the lateral force (Y) on a wheel, caused by lateral forces in curves, the sinus movement, side wind etc. In contrast is the vertical load, the wheel load (Q), which must be strong enough to withstand the lateral load. The typical maximum ratio between Q/Y should be < 0.8. 防脱轨的安全性取决于两个重要的力：车轮的横向力（Y），由曲线横向力，正弦运动，侧风 等引起的车轮上的横向力。与之相对的是垂直载荷，车轮载荷（Q） 必须足够稳固以承受横向 载荷。 Q / Y 之间的典型最大比例应为<0.8。

Safety against derailing depends on 防脱轨的安全性取决于 Page 2 of 13

Page 3 of 13

What influences the correct wheel load? 什么影响正确的车轮载荷？ The main factors influencing the vehicle’s wheel load are the diameter differences amongst the wheels, the primary suspension, a possible twisted bogie frame, the height differences from top of rail to the top of the secondary suspension between the bogie’s left and right side or the front and rear bogies. It is finally also the load distribution within a vehicle body as well as the flatness of the supporting surfaces, contacting the bogies. 影响车辆车轮载荷的主要因素是车轮之间的直径差异，一系弹簧，变形的转向架，转向架左、 右侧或前、后侧之间的轨面到二系弹簧表面的高度差。 以及车体的载荷分布与转向架接触的 支撑表面的平坦度。

Overview of influences on the bogie 对转向架的影响概述

Accordingly, the wheel load is also influenced by the evenness of the track, the train weight and load distribution as well as the aerodynamics in case of trains under higher speeds etc. 因此，车轮载荷也受轨道平坦度，列车重量和载荷分布以及火车在较高速度等级下的空气动力 学的影响。

Components and correction methods:组件和校正方法： Following, we describe more details regarding some vehicle components and possible correction methods. 以下，我们将介绍有关车辆部件和校正方法的更多细节。 The influence of different wheel diameter 不同车轮直径的影响 There are different instruments for measuring the wheel diameters and profiles on a bogie or vehicle. If the diameters between left and right side wheel or amongst all 4 wheels are out of tolerance, EN 15313 < 0.3 mm, the wheels must then be re-profiled or exchanged. It is often several millimetres.

Page 4 of 13

This reason may be explained in a simpler way, e.g.: The imagination of sitting on a four-legged chair, with one leg shorter than the others. While less weight is on the shorter leg, more is on the other three legs. Therefore, the weight (load) is not distributed equally to the other chair legs. 使用不同的仪器用于测量转向架或车辆上的车轮直径和轮廓。 如果左右侧车轮之间或所有 4 个车轮之间的直径超出公差，则 EN 15313 <0.3 mm，则必须修改车轮轮廓或更换车轮。 通常 是几毫米。 可以用更简单的方式来解释，例如：想像坐在一个四条腿的椅子上，一条腿短于其他三条腿。 较短的腿上的重量较轻，但另外三条腿更重。 因此，重量（载荷）不能平衡地分配到椅子腿 上。

Wheel diameter, primary suspension, frame 车轮直径，一系弹簧，框架

The primary suspension 一系弹簧 Springs with different characteristics may have a negative influence to the wheel load. Therefore, during the heavy maintenance, the springs of the primary suspension should be checked by a spring test press. It is important to have springs with similar stiffness characteristics and heights within a bogie. The heights under load can be corrected with primary shim plates. Standards such as UIC 822, EN 13298 or EN 13913 are guidelines how and what is to be tested. Experience has shown that springs are often still in a good condition and can be reused, saving a lot of money. 具有不同特性的弹簧可能对车轮载荷产生负面影响。 因此，在重型维护期间，应使用弹簧试 验机检查一系弹簧。 在转向架内采用类似刚度和高度的弹簧至关重要。 负载高度可以用一系 垫片校正。 诸如 UIC 822，EN 13298 或 EN 13913 标准规定了测试方法以及要测试的内容。 经 验表明，弹簧经常仍处于良好状态，可以重复利用，节省了大量资金。

Page 5 of 13

Fully automatic spring testing 全自动弹簧测试

It is also known that helical springs in particular are moving sideways under increased vertical load.

This is often called “chaise effect” or bowing of springs. If some primary springs under load are moving in the same lateral direction, then the above described side force (Y) will increase automatically and the ratio of Q/Y becomes worse and the derailing safety is reduced. Under such circumstances, more wear on the wheels is the consequence. 弹簧在增加的垂直载荷下发生侧向偏移，特别是螺旋弹簧。 这通常被称为“躺椅效应”或弹 簧弯曲。 如果几个一系弹簧在载荷条件下发生同方向的横向偏移，则上述的侧向力（Y）将自 动增加，并且 Q / Y 比变得更差，并且降低了脱轨安全性。 在这种情况下，导致车轮磨损加大 。

Less wearing, neutralize side force thank testing of bowing angle 弯曲角度的测试可以减少磨损，中和侧向力

Page 6 of 13

EN 13298 (2003) 5.2.3.3 specifies this effect. There are spring test presses available, enabling to determine the bowing direction of springs. The springs can then be marked and installed accordingly so that side forces are neutralized.

EN 13298（2003）5.2.3.3 对此进行了阐述。 弹簧测试压力机，可以确定弹簧的弯曲方向。 然 后可以相应地标记和安装弹簧，来中和侧向力。 Frame check 框架检查 After several years of operation or after crashes, the geometry of a bogie frame should be checked.

Possible criteria are the flatness and the positions of the primary spring guide shafts. The German State Railway “Deutsche Bahn DB” has issued special guidelines, considering also the DIN 27201-9 standards. 在运行几年或者发生碰撞之后，应检查转向架框架的几何形状。 可行的标准是一系弹簧导向 轴的平直度和位置。 德国国家铁路“Deutsche Bahn DB” 发布了特殊准则，同时兼容了 DIN 27201-9 标准。

Function and quality control of bogies 转向架的功能和质量控制 Nowadays, most bogie manufacturers and also many bogie maintenance workshops are equipped with bogie test benches. After assembling the bogie with all its components, the load of the specific vehicle body is simulated by PLC control onto the bogie. 如今，大多数转向架制造商以及许多转向架维修车间配备了转向架试验台。 在组装完转向架 的所有组件后，通过 PLC 模拟特定车体的载荷到转向架上进行测试。

Page 7 of 13

Checking the load distribution and other adjustments on the bogie test stand 在转向架试验台上检测载荷分布和其他调整

The distribution of the load between the wheels and each single wheel can now be determined.

Possible corrections on the primary suspension with automatic calculated shim plates can be carried out. Additionally, the heights of the secondary suspension can be adjusted or corrected under simulated tare load. This is very important, in case of one bogie side with a big height difference, can even influence the wheel load of the bogie at the other end of the vehicle in a negative manner. 现在可以确定车轮和每个车轮之间的载荷分布。可以通过自动加垫计算对一系弹簧进行校正。 此外，二系弹簧的高度可以在模拟自重载荷下进行调整或修正。 这至关重要，如果转向架的 一侧有很大高度差，甚至可以对车辆另一端的转向架车轮载荷造成影响。

Under load simulation, it is also possible to adjust the correct heights of antenna, emergency brakes, coupling heights, etc. The DIN standard 25043-7 is a useful guideline, already considered in bogie

Page 8 of 13

workshops outside Europe. Regarding the wheel load the height of top of secondary suspension (bogie loading point) over T.O.R is be most important. Some rolling stock suppliers request in the their manuals < 2 mm, similar shall be between front an rear bogies. 在载荷模拟条件下，还可以调整天线的高度，紧急制动，耦合高度等。DIN25043-7 标准是一 个实用的指南，已经成为在欧洲以外的转向架车间的参考标准。 关于车轮载荷，二系弹簧顶 部（转向架装载点）过轨面的高度是最重要的。 部分机车车辆供应商在其手册中要求<2 mm ，类似于前、后转向架之间。

Checking heights under simulated load 在模拟载荷下的高度检查

Sophisticated bogie test benches enable the measuring of axle distances, mainly the axle parallelism.

This is a very important criteria which should be checked on bogies. 高端的转向架试验台能够测量轴距，主要是轴平行度。 这是一个非常重要的标准，应该在转 向架上检查。

Un-parallel axles cause wearing and reduce the safety 不平行的轴会导致磨损并降低安全性

It is doubtless, that a bogie with non-parallel axles as shown on this image, tends to always move in a curve, having increased lateral forces and less safety against derailing as a consequence. There will Page 9 of 13

be more wheel wear, noise and vibration. The only method to recognize such a situation and making corrections is on the bogie test bench before the bogie leaves the workshop and causes damages. 毫无疑问，如图所示，具有不平行轴的转向架往往总是沿着曲线移动，因此增加了侧向力并降 低了脱轨安全性， 会加大车轮磨损，噪音和振动。为避免这种情况的发生， 在转向架离开车 间之前，需要在转向架试验台上进行检测和修正。 The 4- corner weighing of the vehicle body 车体四角称重 From where does the workshop know the correct load which shall be applied onto the bogie for testing? It is either from the rolling stock or the locomotive manufacturer , often to be found in the maintenance manual. In case of refurbished vehicle bodies or repairs after accidents, it is recommended to apply the method of 4-corner weighing described e.g. in the DIN 25043-4 standard.

The result is the specific load forces which will be applied onto the bogie contact points. Another useful result of this test is to achieve the calculation of secondary shim plates to equalize the flatness of the contacting points to the bogie. 车间操作员从哪里获悉应用于转向架测试的正确载荷？答案不是 来自机车车辆就是机车制造 商，经常在维修手册中找到。 如果在车体翻新或事故维修后，建议采用四角称重方法，如： DIN 25043-4 标准中阐述的称重法。称重结果是将被施加到转向架接触点上的特定加载力。 该 结果还被用于二次加垫计算，以平衡与转向架接触点的平坦度。

Determination of the load which the vehicle body applies onto the bogie 确定车体作用于转向架上的载荷

The final check of complete vehicles 整车最后检查 Before a vehicle leaves the workshop after overhaul or a preventive control, the balance of wheel loads of the complete vehicle shall be checked. This is the final check against derailing safety of the Page 10 of 13

complete vehicle. There are several testing methods available such as mobile wheel weighing cells, stationary installed wheel weighing bridges. DIN 27201-5 offers the required calculation methods for the maximum differences of wheel loads within a vehicle. Maximum differences between wheels on a bogie < 5% are common . 在大修或预防控制车辆离开车间之前，应检查整车车轮载荷平衡。 这是对整车防脱轨安全性 的最终检查。 有几种测试方法可用，如移动轮称重传感器，固定式安装的车轮称重桥。 DIN 27201-5 标准中提供了整车车轮载荷最大差的计算方法。 转向架上的车轮之间的最大差<5％是 常见的。

Wheel load control in the workshop 车间里的车轮载荷控制

Simulation of the situation at the end of curves or uneven tracks 模拟弯路末端或不平坦轨道的情况 A challenging situation for the wheel load occurs in case of uneven tracks or at the end of curves.

The left front wheel on the left (in driving direction) according to the below photo, receives the smallest wheel load, so called unloading. 在轨道不平坦或弯路末端的情况下，对车轮载荷具有一定的挑战性。 左前轮（行驶方向）根 据下图，承受最小的车轮载荷，称为空载。

Situation of the train at the end of the curve

火车在曲线尽头的情况

Page 11 of 13

The EN standard 14363, chapter A.9.1. describes a method which allows to test the wheel load with twisting track, or in other words the simulation of an uneven track or end of a curve in a workshop.

The unloading simulation and determination of the smallest wheel load can be tested on each single wheel either manually or better by an existing fully automatic test bench. If the difference between all bogie wheels, ∆ Q/Q is out of tolerance, this then indicates that the vehicle is no longer safe against derailing on uneven tracks or at the end of curves. It should therefore undergo immediate maintenance before risking lives or damages. However, if a vehicle passes this test, it is safe against derailing and can continue operation and a scheduled and costly maintenance may be postponed. So this is a very good tool for condition based maintenance.

EN14363 标准 A.9.1 节， 描述了一种使用扭曲轨道测试车轮负载的方法，也就是在车间中模拟 不平坦轨道或弯路末端。 可以通过手动或最好采用现有的全自动试验台对每个车轮进行空载 模拟和最小载荷的测试。 如果转向架上所有车轮之间的差值ΔQ/ Q 超出公差，则表明该车辆 在不平坦轨道和转弯时存在脱轨风险。 因此，为避免事故的发生，应立即进行维护。 然而， 如果车辆通过此测试，则不存在脱轨风险可继续运行，并可推迟定期高额的维护费用。 所以 这是一个很好的视情况进行维护的工具。

What are the challenges?所面临的挑战？ There are still many workshops or maintenance concepts which do not take enough care regarding the importance of the wheel load. 仍然有许多车间或维护概念对于车轮载荷的重要性不太重视。 Safety, reliability and reduced life cycle costs must be one of the most important targets in workshops. Therefore the described practice should be applied and the necessary test equipment should be made available. The necessary investments should be budgeted – with the benefit of reusing springs, less wheel wearing and re-profiling, less unscheduled maintenance, etc. Consultants should implement those technologies into the design of workshops. In some countries authorities applied regulations regarding wheel loads etc. In many countries, they are still missing. 安全性，可靠性和降低生命周期成本必须是车间最重要的目标之一。 因此，应实施上述检测 内容，并使用必要的测试设备。 必要的投资可以降低预算费用 - 重新使用弹簧，减少车轮磨损 和重整轮廓，减少计划外的维护费用等。车间的设计中应包含这些技术。 在有些国家，当局 对车轮载荷等进行了规定，但仍然有许多国家未采用。

Walter Kellenberger Vice President Railway Technology and author of this article Nencki Ltd.

Page 12 of 13

www.nencki-railway.ch

Page 13 of 13