Composite sleepers and bearers formed of polymers and sometimes steel or fibre reinforcement are an alternative to traditionally used timber or prestressed concrete counterparts. Composite materials offer the combined benefits of the compliant sleeper/ballast contact of timber with the longer service life of concrete. However, composite and timber sleepers have lower bending stiffness compared with concrete, and this affects their track performance. To better understand the influence of sleeper material on performance, a concrete and a composite sleeper were tested in the Southampton Railway Testing Facility. Test results were interpreted with the aid of finite difference and discrete element method numerical modelling. It was found that composite sleepers can provide a more compliant sleeper/ballast interface with increased numbers of ballast grain contacts of larger area that attenuate the peak contact forces. However, owing to their lower bending stiffness, they have more exaggerated deflection profiles and a tendency to become centre-bound compared with stiffer prestressed concrete counterparts.

由聚合物以及有时由钢或纤维增强材料制成的复合轨枕和支撑物是传统木材或预应力混凝土的替代品。复合材料具有使木材与轨枕/压舱物保持顺应性接触以及混凝土使用寿命更长的综合优点。但是，复合材料和木材轨枕的抗弯刚度比混凝土低，这会影响其履带性能。为了更好地了解轨枕材料对性能的影响，在南安普敦铁路测试设施中对混凝土和复合轨枕进行了测试。测试结果借助有限差分法和离散元法数值建模进行解释。已经发现，复合轨枕可提供更大顺应性的轨枕/道ast界面，增加了较大面积的道ball颗粒接触的数量，从而减弱了峰值接触力。但是，由于其较低的弯曲刚度，与较硬的预应力混凝土对应物相比，它们具有更大的挠曲轮廓和趋向于中心约束的趋势。