At the McNealy Brown site in Sittingbourne a full-size railway footbridge looks slightly out of place. However, this is the first full prototype of the new AVA, adaptable lift and bridge system, developed by the Network Rail consortium. The Manufacturer’s Molly Cooper went to find out more about footbridge, its development and what this means for the future of access for all.
The AVA adaptable bridge and lift system consortium was created by Anthony Dewer, Professional Head Buildings and Architecture at Network Rail. He brought together several partners to solve the access for all challenges that railway stations face around the country.
Members of the consortium are:
The challenge was looking at the current footbridges that allow us to cross railway tracks to access another platform or exit. “Railway footbridges haven’t changed much in 60 years – and they aren’t being made any differently either,” said Chris Head, Pre-Construction Manager at McNealy Brown. The techniques used in their manufacture have also remained much the same, meaning the delivery time has also stayed quite lengthy. They are also expensive to produce and difficult to maintain, so all in all, the whole process needed to be re-evaluated.
The AVA project is 50% funded by Innovate UK, whose major objectives is to promote British expertise manufacturing, engineering and construction. The project has already had interest globally from Australia, the US and South Korea, and the first AVA installation is due to take place in May 2025 at Stowmarket railway station in Suffolk.
Meeting criteria
Network Rail produce a design manual for footbridges and subways, within which the new AVA bridge is already featured. The manual includes an independent assessment of cost, carbon footprint and several other targets. “When we designed AVA, we had a long list of targets we wanted to achieve which were quite challenging. But to already be recognised in an independent study, reinforces that we reached those goals which has, in turn, endorsed the footbridge too,” said Hazel Needham, Associate Structural Engineer at Expedition Engineering. “AVA scored maximum points in context, passenger experience, safety, maintenance, build ability and cost.”
From the current selection of bridges available, AVA has the lowest CAPEX and whole life cost due to the reduced maintenance requirements. In turn this makes the bridge greener than other options as it has a life span of 120 years. A key feature of the AVA bridge is that it is a modular design, meaning that all connections are bolted together and can be easily replaced singularly if damaged, rather than having to replace whole parts. “If the bridge was no longer needed, it could be unbolted, disassembled and moved elsewhere – or recycled as they are manufactured from sustainable steel – so it is greener in comparison to other materials currently being used,” added Hazel.
Sustainable steel
“The stainless steel used on AVA is duplex, which has over double the strength of the stainless steel that we typically use daily. This allows us to reduce the thickness of the steel required while still maintaining its integrity as a construction material,” explained Bob Atherton from Outokumpu. This type of steel has been used across Europe in various applications but as yet, not in bridges. Due to its strength and wearability, the bridge will look much the same in 100 years’ time as it did on the day of installation. “The stainless steel is around 95% recycled and allows us to get the carbon footprint down dramatically compared to others in the industry,” Bob added.
Currently, footbridges are made using steel which is fabricated and welded together to create the form of a bridge. AVA’s modular design means that it uses sheets of material that are bolted together. Manufacturers are also able to make many standard parts that can be used on each bridge to extend lengths. “In advance of a design being finished, we can have all the standard parts ready to go on a shelf. Then, depending on the procurement pipeline, it is possible to have a whole bridge worth of parts sat ready to go before the scheme is even decided and at which location it is going to be needed,” explained Chris. This way of working is what makes AVA so different from the traditional method of building, installing and maintaining railway bridges.
Access for all
Network Rail has an Access for All scheme to improve accessibility at railway stations and AVA is at the centre of that. With the footbridge, two stairways and two lifts, it allows universal access to platforms and exits.
One of the key focuses of AVA is that it is a footbridge that can be deployed at any train station in the UK, or around the world. Every station has different heights of overlines, platforms and varying numbers of tracks which AVA can accommodate thanks to its modular design.
There are varying orientations in which the AVA can be built including; one/two lifts, narrow lift position or lift at the side. “We can adapt the number of parts needed to make a significant length increase up to a 20-metre span across the platforms. Or, if you need to make a small tweak, you can just laser cut a slightly different length panel to make up that distance. The same works for height; if a small height increase is needed an extra stair can be modularly added,” explained Hazel.
In addition, the bridge can also be built with or without a roof and privacy screens are available depending on the location of the footbridge.
Reduced time on-site
“In the design phase, a key element was how we could reduce the time spent on-site when constructing and installing the footbridge,” said Jim Arnott, Contract Manager at Walker Construction. One factor that is a first for Network Rail, is that the lift is delivered to the site laying down – it is then lifted and fitted directly into place. This enabled a time saving of over 20 weeks for the lift installation alone. Typically, any sort of construction next to and over a railway brings many challenges with scaffolding and time restrictions.
“In a standard scenario, we are estimating 15 weeks for the installation of AVA. First, we break ground and spend 12 weeks putting in the foundations ready for that installation to take place. Then the next two to three weeks is spent finishing off the works on the platform and testing any electrical services,” Jim added. “Overall, the process is 20 months from contract award to delivery of the scheme.”
Lift maintenance
When it comes to passenger lifts, reliability and availability is key, especially on an Access for All footbridge. The AVA lift system has been designed specifically for the constrained rail environment which usually experiences breakdowns with lifts. “We came up with a lift system which is essentially plug-and-play. A recurring issue for current lift stock is failures in the drive system. Therefore, we have incorporated a dual drive system. If one of the drives goes down or is out of service for whatever reason, the second drive picks up the slack and operates at a lower rating. The important factor is the lift stays in service,” explained Darren Falkingham, Market Engagement Manager at Kinetic Solutions Group.
“Traditionally, lifts have flat doors sliding apart from the middle, which is an area of mechanical weakness – instead AVA features a single piece, curved metal door that’s pivots away from a single point and is far more robust than traditional doors, increasing its longevity and reliability,” said Darren.
The key difference in the AVA process is that the lift is built, assembled, tested and certified in the facility before it leaves the factory. The certified components are then transported to the site, where they are installed. Once moved and positioned, they are immediately ready for use.
