This manuscript presents findings from an ongoing research study at Oklahoma State University studying different factors that affect vertical tie reaction forces in ballasted railroad tracks. A combined approach involving field instrumentation and numerical modeling has been adopted for this purpose. Measurements of tie reactions can indicate the load distribution patterns and quality of vertical support along a track. Locations where tie support conditions are not adequate can develop geometry defects, ultimately leading to component failure. Three different approaches are adopted in this study to measure the forces being transmitted through the rail-tie interface; this is equal to the tie reaction force. The field instrumentation effort validates an alternative method to measure forces at the rail-tie interface using rail-mounted strain gauges. Results from this approach are compared to two other conventional methods of force measurement, i.e. through the use of load cells (LC), and an instrumented tie plate (ITP). A validated 3-dimensional Finite Element (FE) model is used to support the field-observed trends, and explain any observed discrepancy. Parametric analyses using the FE model identify different factors that can contribute to the rail-tie interaction force, thus affecting the instrumentation results. The strain gauge-based approach, using the concept of differential shear strain measurement, has been established as a suitable method for tie reaction force measurement. Exact measurement of the tie reaction force can be ensured through proper installation of the strain gauges, away from possible boundary effects.

这份手稿介绍了俄克拉荷马州立大学正在进行的一项研究的结果，该研究研究了影响有砟铁轨中垂直枕木反作用力的不同因素。为此目的，采用了涉及现场仪器和数值建模的组合方法。系杆反作用力的测量可以指示沿轨道的垂直支撑的载荷分布模式和质量。连接支撑条件不充分的位置可能会产生几何缺陷，最终导致组件故障。本研究采用三种不同的方法来测量通过轨枕界面传递的力；这等于系杆反作用力。现场仪表工作验证了一种替代方法，该方法可以使用安装在轨道上的应变仪来测量轨枕界面处的力。将这种方法的结果与其他两种传统的力测量方法进行比较，即通过使用称重传感器 (LC) 和仪表连接板 (ITP)。使用经过验证的 3 维有限元 (FE) 模型来支持现场观察到的趋势，并解释任何观察到的差异。使用 FE 模型的参数分析确定了可能导致轨枕相互作用力的不同因素，从而影响仪表结果。基于应变计的方法，使用差分剪切应变测量的概念，已被确立为一种适合测量系杆反作用力的方法。通过正确安装应变计，可以确保对拉杆反作用力的精确测量，避免可能的边界效应。