The future of composites in railway infrastructure

Modern high-strength composite materials offer ample opportunities for energy-efficient solutions, reducing environmental impact and reducing the life-cycle cost of rail infrastructure. Growing populations and expanding urbanization worldwide require more sustainable mobility solutions to address global resource scarcity and climate change. Network Rail, owner of the UK rail network, has partnered with the National Composites Centre (NCC) in Bristol, UK, to develop state-of-the-art materials and technologies and explore new design concepts for the use of composite materials in the rail industry.

As one of the most sustainable modes of transportation, rail transit systems account for an increasing share of travel demand. According to the International Transport Forum's Transport Outlook 2019, global passenger transport demand will more than double over the next 30 years, while freight demand is expected to triple.

 

Growing passenger demand requires advanced rail infrastructure

Composite materials are already playing an increasingly important role in the transportation industry due to their light weight, durability and low environmental footprint. Composite materials offer significant improvements over traditional materials, enabling innovative and sustainable solutions for a variety of critical infrastructure projects.

Many countries, whether those with well-established or rapidly developing rail networks, are exploring modern composite materials to meet the needs of large-scale infrastructure improvements required by their rail industries.

Consider the United States, for example, given that the US rail network consists of nearly 140,000 miles of track and more than 100,000 bridges, all of which require constant upgrades and repairs, the use of composite materials in the rail industry can significantly reduce infrastructure life-cycle costs. The UK rail network conducts more than 10,000 inspections of timber, concrete and steel structures that are critical to the integrity and reliability of the country's rail transport system.

 

Rail network launches composite pedestrian bridge

The UK's first self-supporting FRP bridge was installed at St. Austell by Network Rail in October 2007 and was designed by WSP. Network Rail then installed the first all-composite station footbridge in Dawlish in 2011 (designed by Tony Gee and Partners LLP, UK, and manufactured by Pipex, UK).

20 years ago, a composite pedestrian bridge named "Futura" was designed by Marks Barfield Architects in London, UK and COWI, an engineering consultancy group in Limby, Denmark. It demonstrates the benefits of using lightweight and durable composite materials in new and replacement structures for rail infrastructure.

Manufactured at the NCC factory in Bristol using modern high-precision manufacturing methods, its concept footbridge components can be precision assembled quickly and directly on site with minimal disruption to rail network operations, road traffic and local businesses.

The technology will allow for architectural alternative infrastructures that aesthetically replicate the features of existing steel or concrete structures, while offering a lighter, more durable solution.

 

High-performance composites for cost-effective rail infrastructure

Prefabricated large components will be compression molded from fiberglass reinforced plastics (FRPs). FRP is a composite material consisting of a fiber-reinforced polymer matrix. Such fibers can be made from glass or carbon fibers, and in some cases paper or wood fibers can be used for biodegradable composites. The polymer matrix in modern composites is usually an epoxy, vinyl ester or polyester thermoset. FRPs are widely used in the aerospace, automotive, marine and construction industries.

Compared with traditional building materials such as steel and reinforced concrete, the main advantage of using FRP composites in railway infrastructure is that the material has higher specific strength and specific stiffness, and ultimately achieves structural lightweighting.

FRPs have excellent corrosion and weather resistance, making them suitable for long-term structural use and reduced maintenance. NCC's latest technology and expertise enables cost-effective FRP components to meet stringent fire, smoke and toxicity standards for a variety of rail infrastructure applications.

 

Widespread use of composite materials in railway infrastructure

From this perspective, this approach will allow composite innovations to be transferred to the wider rail infrastructure, including walkways, station platforms and rail gantries.

The non-magnetic and non-conductive properties of this composite material make it particularly suitable for the manufacture of handrails, fencing and tertiary rail coverings for the UK rail network, where overhead lines and tertiary rail systems account for approximately 40% of the entire rail network, with maximum significantly reduces the risk of fatal electric shock.

 

The Rail Industry's Path Towards Next-Generation Composite Materials

When considering the energy and material resources involved in the manufacturing process, the cost of FRP components appears to be higher than that of traditional steel, both in terms of unit weight and force capacity. However, the direct and indirect benefits of using FRP composites in railway infrastructure, such as rapid assembly of large-scale prefabricated components (less labor requirements), longer life cycles, and reduced maintenance costs, reveal that modern composites are more Competitiveness of traditional building materials.

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