A Review of Natural Fibers Reinforced Composites for Railroad Applications

Composite materials are abundantly present in applications related to transportation industries, mainly due to their lightweight, good mechanical performance, and viable production costs. In this sector, weight reduction represents a two-fold advantage as fuel consumption can be reduced, as well as passenger (or load) capacity can be enhanced. The use of natural fiber composites is an excellent option considering weight reduction and source renewability, already being done in many automotive and aerospace utilities, but specifically in railroad applications, their choice seems to be eclipsed by synthetic fibers, such as glass and carbon fibers. The objective of this work is to analyze the current situation on composite applications in the railroad industry, deriving a discussion that includes the aspects that hinder the use of natural fibers and also indicates the current status of greener composites even if not including natural fibers. The production costs of these natural fiber-reinforced composites, when observed under a scalability scenario, associated with some specific properties of natural fibers (as flammability performance, for example) seem to be the reason for their rather infrequent consideration. Nevertheless, technology advancements related to production processes and innovative additives fabrication present an interesting prospect for future development in agreement with sustainability concerns.