Network Rail’s modular footbridge that can adapt to almost any railway station 

When Anthony Dewar was appointed as Network Rail’s Head of Buildings and Architecture in 2018, he took the opportunity to realise a long-held ambition to make footbridges better: “I worked on my first footbridge 20 years ago and I thought that there must be a better way. We design, fabricate and build footbridges today in the same way we did in the 1960s. Every project is bespoke and must be tailor-made for the peculiarities of its site.” 

This traditional approach takes time and budget, and in turn limits how many footbridges that Network Rail can build. That is a challenge as the operator faces growing demand. Around 1000 of the UK’s small and medium stations are not equipped with a footbridge at all, whereas many of the existing 1500 station footbridges are ageing assets.  

To overcome this, Anthony is overseeing the AVA Bridge project to deliver better bridges that are cost effective, faster to deliver, have a lower carbon footprint and that enhance passenger experience. 

In June 2024, a prototype and demonstrator bridge was installed in Sittingbourne, Kent to give stakeholders an opportunity to see the bridge in a real-world setting.   
 

Combining bridge design with modern manufacturing 

“A station footbridge is more than just a connection across the tracks. A well-designed footbridge also provides a sense of security and inclusion, which is important for people travelling alone and for people with accessibility needs,” says Anthony.  

“There’s also a wider benefit to society. When we add a footbridge to a station, we immediately see passenger numbers grow. It encourages economic development. Also, a footbridge is a visible landmark that creates a sense of place so we should ideally be building bridges that look good as well.” 

However, the project also addressed the challenge of developing a bridge design that can be adapted to the huge variety of station layouts on the UK’s network.  

Anthony set up the AVA Bridge project consortium after seeing the ideas generated by a 2018 competition that Network Rail held with the Royal Institute of British Architects (RIBA) to explore new concepts in bridge design. Entrants considered structural and architectural design, constructability, materials and modern techniques for construction, fabrication and manufacture. 

Funded by the UK’s national innovation agency InnovateUK and Network Rail, the AVA Bridge project was delivered by a consortium. Its members include Walker Construction who are leading and managing the project. They are overseeing other members including construction contractor McNealy Brown, as well as input from the Manufacturing Technology Centre (MTC), an independent research and technology organization. Architecture practice Hawkins\Brown and built environment practice Expedition Engineering designed the bridge, while ARX are overseeing the passenger lift. Outokumpu began working with the team early in 2021 and brought knowledge of stainless steel.   

Together, the consortium members have developed a modular design that takes a completely novel approach to bridge design. Whereas a traditional bridge is based on welding I-beams together to form a frame, the AVA Bridge has taken inspiration from modern digital manufacturing techniques. 

Modular bridge design 

The goal was to apply principles of mass manufacturing and modularity to bring bridge construction into the 21st century.  

“It is similar to the way that Henry Ford revolutionized car production with the Model T production lines,” says Anthony. “In the case of the AVA bridge, the aim is to use a modular design with interchangeable components. It should be straightforward to adapt the bridge for the vast majority of station configurations that we have in the UK.”  

Rather than being fabricated the traditional way with a superstructure based on I-beams, the design is more like a Meccano kit made from many small components that have been laser cut and bent from a flat plate of stainless steel. These are bolted together into sub-assemblies and then into major assemblies that integrate lighting and services – all carried out in factory conditions to ensure quality.  

The modular approach makes it possible to adjust the height and span of the bridge, as well as the number, size and skew of the platforms.  

Once it is ready to deploy, the major assemblies of a bridge can be transported by truck and are craned into position with minimal construction work required on site.  

AVA is the latest edition to Network Rail’s Footbridges & Subways Design Manual. An independent assessment commissioned by Network Rail awarded AVA maximum points for sustainability, passenger experience, safety, maintenance, and costs compared to other approved Network Rail footbridges.  

 

Project savings and lifetime benefits 

The consortium has estimated huge potential savings. A traditional footbridge project with two lifts and two platforms typically takes up to 12 months and costs £3-4 million. Using stainless steel as the construction material, Network Rail expects the AVA Bridge to cut CAPEX, reduce overall project time and lower carbon footprint. A further maintenance advantage is that it uses a type of lift that has been developed to be  more reliable.  

While modern manufacturing techniques have a major influence over project delivery, the choice of corrosion resistant and high-strength stainless steel is also important. The project is using Outokumpu’s Forta LDX 2101. This is a lean duplex grade with high mechanical strength that enables design of a lightweight structure. Furthermore, the corrosion resistance provides a long life and with an attractive finish that has no need for coating or painting.  

It’s anticipated that the AVA Bridge will last at least three times longer than a traditional bridge and will cut maintenance budgets as it will not need painting. This is a major saving as carbon steel bridges need repainting every 30 years. 

 

Surface finish that lasts 

Because it remains unpainted, Anthony is hopeful that the surface finish will lead to less tangible benefits for communities. 

“We have chosen a bead blasted finish, which is similar to an iPhone and has a crisp feel that’s quite different to a traditional steel fabrication finish. This is important as our annual national passenger survey always finds that station upkeep is the top driver of passenger satisfaction. People have told us they care about the built environment more than they do about trains arriving on time. So, we hope the AVA Bridge will help them feel better when they pass through stations.” 

Meanwhile, the design’s robustness has undergone extensive testing in terms of how well it can withstand vandalism. It found the bridge is extremely durable and resists graffiti and deformation. And, with the bridge being modular, it’s possible to replace a damaged component.  

 

Open source design 

Having benefited from public funding, the project has been developed with an additional objective to promote the development of digital manufacturing skills in the UK.   

In support of this, the AVA Bridge will be an open source design at the end of the project. In theory, any structural engineer and manufacturing workshop will be able to work as a team to adapt the bridge design for a given site.  

As a modular design, the bridge can be adapted to suit the vast majority of small and medium sized railway stations. There is a small minority of stations where operators should consider alternatives, for example when a long span is needed. Additionally, the choice of Forta LDX 2101 stainless steel is ideal for the majority of urban and rural sites but this can be upgraded for seafront or coastal locations. The alternative grade of Forta DX 2205 has higher corrosion resistance and was used to build the Helix Footbridge in Singapore, as well as the Aguilas Footbridge in Spain.  

Anthony concludes: “We’re looking forward to seeing the bridge in action. It’s generating a lot of interest from Network Rail’s regional teams, from the world of highways and from outside the UK. But before we can roll the bridge out, we need to see it in a real-world environment at Widmerpool station.”   

The first bridge is expected to open in summer 2025 at Stowmarket Station in the UK.