Electric-Resistant Paint Saves UK Rail Bridge
In what is believed to be a world first, engineers from Network Rail—owner of Network Rail Infrastructure Ltd in London—recently avoided the demolition of a Victorian-era railway bridge by utilizing electric-resistant coatings technology.
The specialty paint is believed to have saved an estimated $56 million in costs for the potential demolition and rebuild of Intersection Bridge. The coating was developed at the University of Southampton.
According to reports, electrification of the railway between London and Cardiff was completed just over a year ago, as the United Kingdom replaced its diesel trains with electric ones. To accommodate the new railcars, Network Rail was tasked with installing overhead wires and cables along the routes. Unfortunately, most railways were constructed during Victorian times and often required reconstruction prior to wire and cable installation.
“Intersection Bridge—situated in the center of Cardiff, on the Wales route—is a prime example. The structure is too low to safely fit all the kit required,” said Richard Stainton, an engineering expert at Network Rail.
“Ordinarily, this would force Network Rail to demolish it and rebuild it at a greater height to keep electric trains a safe distance away from the bridge as they pass under, and stop them from electrifying the bridge itself, or anything on it.”
@networkrail reveals how Cardiff bridge avoids £40m demolition thanks to electric resistant paint - “This solution will allow future electrification projects to be installed” without multi-million-pound expenditure – potentially saving the tax-payers as much as £100m.— Rail Professional (@RailProMag) February 24, 2021
To avoid reconstruction, workers coated the underside of the bridge with an electric-resistant coating, which was used alongside a specially developed lineside kit, which included surge arresters and insulated bridge arms to insulate the bridge from electricity and make it safe for electric trains to pass under.
In doing so, the electric-resistant coating in combination with voltage-controlled clearance allowed for the electrical clearance gap to be reduced by 20mm from the overhead line equipment to the bridge, and 70mm from the OLE to the train roofs.
“It's a really complex situation at Cardiff Intersection Bridge. It's a very busy rail-over-rail bridge, with a canal underneath that, and it's surrounded by high-rise buildings,” said Peter Smith-Jaynes, Regional Asset Manager, Electrification, Wales & Western. “Just accessing the bridge would have been difficult but knocking it down and rebuilding it would have been nearly impossible. We had to find another solution.”
Stainton also chimed on the railway’s solution, noting that it would save enormous efficiencies and could allow for future electrification projects to be installed and energized in a way that saves taxpayers millions of pounds.
Smith-Jaynes echoed Stainton, concluding that, “As a Welshman, I'm proud we've been able to trial this innovative, new technology here in Cardiff, and can look back on it knowing we've made a difference, potentially saving the taxpayer millions as we roll it out on future electrification projects elsewhere."
National Rail is currently investigating the possibility of deploying the coatings technology across the United Kingdom.
Other Coatings Technology
Not long ago, in 2018, the University of Southampton was recognized for another coating technology development, a new type of first-surface coating for spacecraft exteriors with light weight and durability that they say could change how craft are designed. Known as Metamaterial Optical Solar Reflectors, or Meta-OSRs, the coatings radiate infrared heat away while reflecting most of the optical solar spectrum.
According to the university, the OSRs are an essential component of thermal control for spacecraft.
Most commonly made from of quartz tiles with thermo-optical properties, OSRs are designed to reject solar radiation and dissipate heat generated onboard the spacecraft. The tiles themselves are often heavy and fragile and cannot be applied to curved surfaces.
The research team developed a new meta-OSR coating that uses metal oxide, a material used for transparent electrical contacts. In this context, the oxide “is patterned into a metamaterial with very strong infrared emissivity while retaining a low absorption of the solar spectrum,” according to the university.
Otto Muskens, professor and principal investigator of the study, noted that the newly developed OSR technology is based completely on durable coatings that are approved to be used in space.
At the time, the research team was working on developing the prototypes for larger areas, through processes developed by NIL Technology. The first round of tests for the metamaterials is still being prepared.
The University of Southampton was supported by the Horizon 2020 space technology project, and is a member of the META-REFLECTOR consortium. Members include Italian research center Centro Ricerche Elettro-Ottiche, Thales Alenia Space and Danish nanoimprint developer NIL Technology.
In relation to electric-type coatings, in 2016, researchers from the Ulsan National Institute of Science and Technology (UNIST) and the Korea Electrotechnology Research Institute announced its development of a thermoelectric paint that aims to capture the waste heat from hot painted surfaces and convert it into electrical energy.
Paint that can be used to produce power is not a novel concept; photovoltaic paint or “paint-on solar cells” has been in the works for years. However, this thermoelectric paint technology is different.
The team’s paint combines bismuth telluride (Bi2Te3) with molecular sintering aids and can be applied with a brush to flat or curved surfaces, making possible applications wide ranging.
It differs from conventional thermoelectric materials, which are typically fabricated as flat, rigid chips.
“These devices are then attached to irregular-shaped objects that emit waste heat, such as engines, power plants, and refrigerators,” the report said. “However, the incomplete contact between these curved surfaces and the flat thermoelectric generators results in inevitable heat loss, decreasing the overall efficiency.”
On the other hand, the new thermoelectric paint can be applied to any heat source, regardless of shape, type and size, said Son. Further, the material tests indicate a high output power density (4 mW/cm2 for in-plane type devices and 26.3 mW/cm2 for through-plane type devices).
The study was supported by the R&D Convergence Program of National Research Council of Science & Technology (NST); the Global Frontier Project and New Researcher Support Program by the National Research Foundation (NRF); and the Ministry of Science, ICT and Future Planning (MSIP) of South Korea.