Achieving cost savings by providing lighter weight components was top of mind for U.K.-based Penso Group when it unveiled its CFRP train door last year. The press-formed phenolic prepreg door, with an integrated core sandwich panel, reportedly provides a 30 percent reduction in weight compared to standard aluminum doors.
Train doors are a critical area in need of innovation, according to Shift2Rail, a European initiative supporting improved trains and more durable and cost-effective rail infrastructure. The group encourages the development of doors that move away from current solutions based on honeycomb, aluminum or steel sheets, which have drawbacks around energy consumption, as well as noise and thermal transmission.
The organization is pushing manufacturers to use composites as the foundation of train door systems that open and close more quickly than today’s systems, while meeting necessary safety and reliability levels. An uptick in door speed could reduce people’s time spent on the platform and increase overall line capacity.
Penso reports that by using processes such as hot compression molding and high-pressure resin transfer molding (HP-RTM), the company is able to achieve process cycle times of four to 15 minutes, respectively. This production speed is key to making the use of CFRP more competitive against traditional materials. The company has recently invested in a new plant and equipment with support from Great Britain’s recently launched Rail Supply Growth Fund aimed at helping businesses grow their capabilities and capacity to meet need in the expanding rail supply sector.
Improving Outdated Infrastructure
Many countries are also finding that composites can help lead the wide-scale infrastructure improvements necessary in the rail industry. And there’s much work that needs to be done. Consider, for example, that the U.S. rail network is comprised of nearly 140,000 miles of track and more than 100,000 bridges. The 2017 Infrastructure Report Card issued by the American Society of Civil Engineers noted that the average age of major Northeast Corridor backlog projects – those between Boston and Washington D.C. that require upgrade and repair – is 111 years old. Everything on this list from tracks to moveable bridges is overdue for an overhaul.
Dura Composites’ patented ballast retention system consists of a gray open-mesh grating (which forms the inspection lid) and white GFRP ballast board (which helps to retain the ballast or gravel that forms the bed of the railroad track). The system allows inspectors easy access to hidden critical parts of rail infrastructure to facilitate key safety checks. Photo credit: Dura Composites
In the meantime, routine maintenance of aging infrastructure is critical. Network Rail, the owner of Great Britain’s rail infrastructure, conducts approximately 10,500 annual inspections of the timber and steel structures buried in ballast (gravel that forms the bed of a railroad track), concrete or other materials to ascertain their condition without damaging the structure itself or disrupting rail services. Using an easy-to-remove composite grating to cover the timber and steel structures can make such inspections quicker and less expensive, according to Dura Composites.
Typically, conducting track maintenance requires downtime when trains don’t run. As a result, infrastructure solutions that last longer than traditional products – or eliminate downtime altogether – can lead to significant cost savings for rail systems. Maintenance costs can also be reduced by using lightweight composite solutions for applications such as station platforms rather than concrete ones that require heavy machinery to lift materials on and off site.
As Bowman points out, “The lightweight, high-strength and non-conductive nature of composite materials and their ease of handling allows for work to be carried out at difficult locations where a more traditional approach would be a logistical nightmare.”
Ferme Park railyard in London replaced its concrete troughs along the trackside walkway with Dura Slab GFRP duct cover. By using 43-millimeter Dura Slab Light, consisting of a 38-millimeter thick grating with a 5-millimeter solid top, the railyard was able to protect service equipment with a cable trough covering that could be easily removed for rapid maintenance. Dura Composites says its GRFP solution was chosen because traditional concrete troughs have a tendency to suffer from corrosion and sporadic failures, rendering them unsafe.
The company’s Dura Platform provides a similar solution for station platform maintenance. The pultruded GFRP platform, utilizing various grades of polyester, vinyl ester and proprietary resins, was developed in compliance with standards set by Network Rail to rapidly replace or overlay damaged platforms in modular sections. For example, more than 2,500 square feet of concrete platform at Needham Market train station in England was replaced with Dura Platform in only 36 hours.
“Habitually, these types of platform projects take eight to 10 weeks to complete using traditional materials,” Bowman says. And according to the company, the composite platform replacements can be performed at similar or lower overall costs than concrete.
Overcoming Common Challenges
“We are definitely seeing a huge increase in the use of GRP for the rail industry, both in the U.K. and overseas, thanks to its compelling lifecycle cost and overall versatility,” Bowman says. However, there are still hurdles to broader growth.
“The use of composites requires a change of mindset for some customers who have traditionally used concrete and may not be aware of the benefits of composites,” says Bowman. For example, there’s a perception among some rail operators that GFRP is not as strong as concrete, while in reality it offers an incredible strength-to-weight ratio, he says.
Companies like Dura Composites continue to develop new materials and technologies to increase the potential strength and cost efficiency. “We are exploring the use of hemp instead of glass due to its improved environmental impact, product strength and natural resin compounds,” Bowman says.
But perhaps the biggest challenge related to composite materials is the initial cost. “It can be higher for composites than for some traditional materials thanks to their highly-engineered composition,” says Bowman. “However, GRP products compete very favorably on a performance/life cycle cost basis versus traditional materials.” When rail owners factor in high initial costs of installation – for example, the costs of using cranes to lift concrete trench covers or the cost of equipment to remove concrete components for routine inspections – then composite products become much more competitive with traditional materials.
These cost arguments may prove critical in moving composites into broader infrastructure applications, as funding is a challenge for improvements in many countries. For example, a May 2017 poll of Californians performed by J. Wallin Opinion Research found that only 12 percent of voters want to maintain their financial commitment to the nation’s first high-speed rail project as its projected cost has ballooned from $40 billion to $64 billion. And a 2015 study by the European Parliament on railway infrastructure financing concluded that the European Union’s railway policy “is a long-term challenge” due to fragmentation of railway systems, their poor conditions in many regions, and varying levels of investment support from member countries.
But ground-up projects such as California’s high-speed rail are exactly where composite materials can do the most good in reducing long-term maintenance and providing a more cost-effective ride. It’s up to the composites industry to make its case before outdated infrastructure that’s too expensive to improve upon makes the railroad a treasure of the past.
