Research and Development Trends rends in Contemporary Railway Materials

Material Engineering Research Division

    While appreciating safety as the obvious prerequisite in rail transportation services, railway materials must reconcile performance and economic efficiency more than ever before in order to meet highly developed, diversified requirements. It is also necessary to be able to compete as well as to cooperate with other transportation facilities. Furthermore, recent years have seen an increased demand for ready-made solutions to global environment issues. Through assessment from a perspective of economic efficiency and the environment, an approach has been proposed that incorporates aspects of lifecycle and external economy.

    Cost reduction is essential in establishing a competitive rail transportation system. Component members with a longer working life, along with effective maintenance work, must be established in order to reduce the costs of maintenance. For ground structures, developments are being made to methods for the quality evaluation of deteriorated concrete materials, deterioration diagnosis and the technical development of repair operation. Proposals are also in the pipeline for a life-extending painting process for steel-based bridges and the development of bainite rail for features such as anti-shelling rails. Measures implemented for vehicles include the development and realization of rubber air hoses for long-life vehicles and research into grease pocket profiles to extend the period between replacements of sealed grease.

    Enhancements in the performance and functionality of materials for improving railway services have included advances in the functionality, reliability and durability of adhesion improvement material jetting (Cerajet), which prevents wheel slip when trains start or run through steep grade sections and increase of emergency braking distance in the Shinkansen trains. Developments have also been made to the carbon-based slider for large current collection capacity.

For environmental compliance, recycling methods have been investigated for materials that are difficult recycle such as polyvinyl chloride (PVC), fiber-reinforced plastics and composite materials. Successful recycling techniques have also been reported in terms of economic benefits. Additionally, biodegradable grease has been developed to apply to turnout floor board grease (one of the main sources of waste grease in the environment), solving one of the challenges of ecomaterialization.

    In evaluating the effects of railway materials on the environment, factors such as the presence or absence of harmful materials, recycling efficiency and lifecycles may be considered as individual items. However, for overall evaluation throughout the entire lifecycle of materials, the technique of LCA (Life Cycle Assessment) has become widespread and established. This technique has been applied to components used in railways, and evaluation of the overall railway system has been carried out.

    In order to promote the application of high Tc superconductive material in the railway industry, fundamental research has been carried out into the enhancement of superconductivity (critical current density Jc) and material characteristics (mechanical strength). The development of a superconductive main transformer as an practical application to the vehicle has been undertaken in order to reduce weight and improve conversion efficiency, and the feasibility of such a system has been proven.

    The application of new functional materials in the railway industry includes research into developments such as anti-bacterial concrete, photocatalyst paint and high grade damping alloys. The key words for new material development can be said to be: 1) Nano-technology; 2) Multi-functional practice; 3) Systemization (materials and devices, structure integration, safety and reliability); 4) Materials and environment, and 5) Bio-technology. Developments in railway materials should be made bearing these key words in mind. It should be noted that in such a sector, where the relationship with the social system or regime is important (as with intelligent materials or the eco-material field), increased cooperation is required between each application field and correlated field.