Advanced materials such as plastics and composites have been invented and adopted for bespoke products in railway industry. For instance, they have been employed as railway track sleepers, switches and crossings' bearers, bridge transom girders, and so on. Railway track sleepers and bearers are essential for operations that enhance safety and reliability of railway turnouts. The degradation mechanism of railway sleepers/bearers is attributable largely to the type of materials used. The utilisation of composite material as turnout bearers, located in railway switches and crossings, has resulted in many questions whether they can experience aggressive environments. In reality, the dynamic properties of bearers play a key role in the serviceability performance of the switches and crossings. Exposed to high-intensity impact loading condition, switches and crossings withstand excessive vibrations, which can disable crawlock or signalling gear systems. Even though such effects are well-known, the influence of environmental variance on the dynamic properties of the bearers has yet been determined thoroughly. The goal of this investigation is to identify the influence of wet and dry conditions for the practical guideline and design solutions using composite materials for railway turnout systems. In this investigation, 'fibre-reinforced foamed urethane (FFU)', is emphasized since FFU has been installed in several railway switches and crossings globally. The dynamic properties of the FFU materials will be identified using the instrumented impact hammer testing method. The dynamic damping property of FFU can be calculated by exponential curve fittings, and logarithmic decrements. The results show that FFU on average absorbs less than 5% of water. Interestingly, the water absorption has led to the increment in dynamic moduli in both fibre-grain directions up to 16%.