Major growth in rail traffic in many parts of the world in recent years has brought railway networks close to capacity and restricted the time available for track access to carry out maintenance work without costly temporary route closures. There are, therefore, significant benefits in designing or modifying ballasted track systems to reduce maintenance and associated access requirements. Under sleeper pads (USPs) offer the potential to extend ballasted track system life and to extend the intervals between routine maintenance. This paper presents and evaluates field measurements, made using geophones and high speed filming with digital image correlation (DIC), of the performance of a renewed section of track incorporating two switches and crossings (S&C) over a period of two years. One S&C was fitted with two types of USP (categorised as medium and soft), while the other had no USPs and acted as a control. Measurements demonstrate that the bearers with USPs fitted showed less variability in movement than bearers without USPs fitted. The provision of soft USPs caused large increases (>40%) in vertical bearer movements relative to bearers without USPs, although the medium USPs showed little difference. Increased movements of elongated bearers supporting both tracks fitted with soft USPs led to increased bearer rotations towards the loaded track. This effect was aided by the rigid steel collar fixing in the middle of the bearer used in this design of S&C, and raises questions concerning the desirability of this feature. DIC measurements showed that the at rest position of the elongated bearers rotated towards the track on which a train had most recently passed.

中文翻译：

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道岔和交叉口处枕木垫的行为 – 现场测量

近年来，世界许多地区铁路交通的大幅增长使铁路网络接近容量，并限制了可用于轨道进入以进行维护工作的时间，而无需代价高昂的临时关闭路线。因此，设计或修改有碴轨道系统以减少维护和相关的访问要求具有显着的好处。轨枕垫 (USP) 提供了延长有砟轨道系统寿命和延长日常维护间隔的潜力。本文介绍并评估了使用地震检波器和具有数字图像相关 (DIC) 的高速拍摄的现场测量结果，对包含两个道岔和交叉口 (S&C) 的更新轨道段在两年内的性能进行了评估。那些＆C 装有两种类型的 USP（分类为中等和软），而另一种没有 USP，用作对照。测量结果表明，与未安装 USP 的承载者相比，安装了 USP 的承载者显示出较小的运动可变性。相对于没有 USP 的承载，软 USP 的提供导致垂直承载移动的大幅增加 (>40%)，尽管中等 USP 几乎没有差异。支撑装有软 USP 的两条轨道的细长承载体的运动增加导致承载体向负载轨道的旋转增加。这种效果得益于施恩禧设计中使用的承载器中间的刚性钢轴环固定，并引发了有关此功能可取性的问题。