Rail track longevity is a primary concern for the railroad industry in the US. Therefore, it is important to study the rail support system in detail. This includes understanding the interactions between the rail, the different fastening components, and the crosstie. Then evaluate the support system’s long-term performance. Over the past several years, the railroad industry in the US has been leaning toward implementing alternative solutions to the traditional hardwood timber crossties. Recycled plastic composite crossties present an appealing and effective solution due to their sustainably, environmental benefits, durability, and ease of installation. Several US manufacturers are currently offering commercial crosstie solutions using different recycled plastic composite materials. Thousands of composite plastic crossties are currently in service in a wide variety of railroad tracks. Researchers have investigated this material in the past; however, additional research is still needed to fully understand the rail support system and its long-term behavior. This paper presents an experimental investigation aiming to understand and assess the performance of the full rail support system: the rail section, fastening assembly, and recycled high-density polyethylene crossties. The study encompassed a comprehensive experimental investigation using static and cyclic test methods recommended by the American Railway Engineering and Maintenance-of-Way Association manual. The static tests addressed the performance of the rail support system when subjected to uplift forces and longitudinal loading in the direction of the rail track, e.g. breaking and traction forces. The dynamic test evaluated the long-term behavior of the rail support system while being subjected to repeated loading for three million fatigue cycles. The outcomes of this study showed great results; the crossties survived the fatigue loading with normal wear and minimal degradation, which highlights the potential of these materials if properly optimized and engineered.