This article was originally published by Capacity Media on 2 December 2025. Read the article here.

Boldyn Networks is four years into a 20-year contract with Transport for London (TfL) to offer connectivity across the entire London Underground (the Tube) network.

The project is a collaboration between both organisations and the major UK mobile operators – Three UK, EE, Vodafone and Virgin Media O2 – to provide a neutral host system throughout 137 stations and 217 tunnels.

Boldyn Networks chief operating officer, Nick Hudson, recently provided Capacity with a progress update for the project, its challenges and how the company is committed to advancing networks worldwide.

“We are about 45% through the deployment in the stations and about 35% through the deployment in the tunnels and we’re due to finish in December 2026,” Hudson explained. “It’s a collaborative partnership and a good example of a private partnership that’s working really well in providing huge benefit to London.”

How is 5G being delivered to the Tube?

TfL is working with Boldyn Networks to support improved mobile coverage across London, which includes installing ‘small cells’ transmitters to enhance mobile coverage and capacity.

The company is also working to deliver new gigabit fibre to public centre sites and CCTV sites across London.

“We’ve got nine data centres and we provide mobile phone coverage to areas that are hard to cover. Instead of operators building their own individual systems, we build one system and the operators put their equipment into our data centres that are in strategic places across London,” Hudson said. “We run fibre from what we call a base station hotel – the data centre – down to the top of the station and distribute that out to the platform areas and to the ticket halls.”

The company also has high-power radio networks that sit at each end of a platform to provide coverage in the tunnels, in addition to the stations.

“We’ve invested around one billion pounds today,” Hudson added.

A project of this scale is not an easy task, given the confined space and heritage aspects of the Tube network. Hudson breaks down some of the main challenges Boldyn Networks has encountered so far.

“Safety is our first challenge. It’s a hugely dangerous environment, so broken down into its most basic form, it’s about ensuring that all our engineers go home safe,” he said.

“We also only work between 12am and 4am and cannot store tooling at the stations and the tunnels, which can be very restricting.”

He added: “A lot of the installation work must be in-keeping with heritage requirements. We go through a huge amount of assurance processes with TFL, as well as all the standards around safety and complying with all their standards for power and so on.”

Another major challenge, as those who take the Tube regularly will be aware of, is cooling. Given the temperature in parts of the network and the equipment Boldyn Networks deploys generating a lot of heat, has been a significant issue for the project.

“We’re just making it hotter in some respects,” Hudson said. “Putting cooling down and finding space for cooling is a challenge, but generally it’s the environment that is the most restrictive issue for us.

“We’ve currently got about 320 engineers every night doing this work, which will only increase as we get towards the end of the programme.”

The UK 5G challenge

In the UK this year, there have been plenty of conversations over how the country has perhaps been slower to adopt 5G than most. Significant barriers to full 5G remain, including in hard to reach, more rural areas, which is delaying potential.

Through the TfL project, Boldyn Networks is looking to speed up connectivity.

“Public safety is a key driver for us and TfL,” Hudson said. “It is driving that need and want for more connectivity to allow people to be more productive economically with their time, so they can work on the go.

“We’re seeing a huge amount of data being driven through the network day by day, so it’s certainly stimulating growth.”

In addition to London Underground coverage, Boldyn Networks is also providing coverage above ground through some TfL assets, including streetlamps, CCTV poles and traffic signals.

“We’re starting to deploy 5G on those assets to improve connectivity not only underground but also above ground,” Hudson added. “As more customers use data services, mobile companies struggle to provide capacity when they’re only providing service from the rooftops.

“Bringing the coverage down closer to the user at street level allows more capacity, more bandwidth and better throughput. It’s certainly a catalyst for further investment in data services as opposed to voice services.”

Already, most of the West End and Zone One of the Tube network has been connected, Hudson told us. Now, the project is moving out to the less busy stations and focusing on big complex stations, including King’s Cross and Baker Street – both very well-known and historical sites.

“We’re making good progress,” he said. “We do a lot of work on the New York subway and on the San Francisco BART system, but the Tube tunnels are a lot tighter.”

Prioritising interconnection

More broadly, Boldyn Networks is also growing in the WiFi space, having made some acquisitions in the US around sports and music venues.

“We connect a lot of NBA and NFL stadiums and do about 750 events a year over in the US, in addition to some football grounds and music venues in the UK – that’s a huge growth area,” Hudson said.

Recognised as an industry trailblazer, Boldyn Networks was recently named a leader in private 5G services by Forrester. Hudson credits the company’s progressive work on private network technology as the reason for this recognition.

“We’re deploying private networks through acquisitions we’ve made,” he explained. “We’ve made acquisitions in Europe and that’s given us footprint into markets that we didn’t have before, like Germany, Spain, France and the UK.

“We’re doing some ports, which are a good use case for private networks in the UK. We also have some wind farms on the north coast where we’re providing private networks to allow boats and workers on the wind farms to communicate with each other.”

He added: “Private networks is a huge area of growth for us. We were lucky to win that award and we just need to build on that now.”