Muhammed Emin ARI, Cahit Bilgi, Bilge Demir
Abstract Rapid advancements in modern transportation systems have increased the demand for lightweight, high-strength, and energy-efficient structural materials in railway vehicles. In this context, composite materials are emerging as a strong alternative to traditional metallic materials, offering superior mechanical performance, design flexibility, and potential environmental benefits. Although composite materials have been extensively studied in the aerospace and automotive sectors, their systematic evaluation in railway vehicle engineering remains relatively limited. This review provides a comprehensive assessment of lightweight composite materials used in railway vehicles and addresses major material classes, including fiber-reinforced composites, polymer-matrix composites, metal-matrix composites, nanocomposites, and hybrid composites. The study compares the characteristic properties and structural functions of these materials, as well as their potential applications in various railway vehicle components, including bogies, vehicle bodies, and internal structural elements. Literature data indicate that composite materials can achieve weight reductions of up to 50% in bogies and approximately 40% in vehicle bodies. Additionally, it has been reported that nano-scale additives can increase the tensile strength of carbon fiber-reinforced polymer composites by up to 92.1% compared to neat composites. In addition to summarizing the latest technological advancements, this review critically evaluates current challenges in railway applications, including structural performance, durability, manufacturing constraints, cost factors, and sustainability. By integrating material classification, component-based applications, and performance evaluation within a comprehensive framework, this study aims to serve as a systematic reference for researchers and provide a decision-support perspective for future designs of lightweight, safe, and sustainable railway vehicles.