Thales performs critical refresh of London Underground’s communications network

• Thales has successfully replaced core elements of the London Underground’s radio communications system Connect, used by operators for critical communications
• The new system replaces legacy equipment which has parts that are more than 20 years old
• The Connect system is key infrastructure for running safety-critical operations across London Underground’s 250 miles of track, both above and below ground, and the 270 stations.

Work on replacing the core elements of London Underground’s radio communications system, Connect, has been completed without any disruption to passengers and in the midst of a global pandemic, making the transport system safer and more resilient for its millions of passengers.

During the past 20 years, London Underground has worked with Thales to build, install and run Connect, a robust, unified radio communication system that works above and below ground. 

Thales staff  have been working for the past two years to install the new system and remove the legacy equipment it replaces, while London Underground has continued to operate. Across the 270 station network, engineers upgraded the Connect system, redirected base stations and controls, without interrupting services.

This project has been like changing a car’s engine from petrol to electric, while it is being driven. In an ideal world the system would have been replaced, installed, tested and switched over while the old network was off, but if we had done that, then the London Underground would have needed to stop running temporarily. Instead, we have been able to keep key workers moving around London during the pandemic.

^{Thales’s Programme Director, Peter Gaylor}

The Connect system is key infrastructure for running safety-critical operations across London Underground’s 250 miles of track, both above and below ground, and the 270 stations. It links controllers, drivers and stations staff as well as carrying images for the CCTV system.  The upgraded radio core equipment enables greater functionality and features to be implemented going forward as new technologies and requirements emerge, whilst maintaining safety standards.

Supporting the Emergency Services

Radio signals are propagated by a dedicated network of radiating cables that run from basestation sites at each station along every tunnel and throughout every station. Above ground coverage is provided by similar radiating cables and antenna systems as necessary.

The system, comprising of Motorola DIMETRA hardware, uses TETRA technology and supports Airwave, the national operator for emergency services radio communications. This enables parallel emergency services radio coverage underground, allowing responders work underground while staying in communication with surface units.

Working during a pandemic

Working during a global pandemic added to the challenge of this complex, two-year programme. Nobody had heard of COVID-19 when planning work commenced but the pandemic put limits on the numbers of workers allowed in a workspace as well as requiring as many as possible to work remotely to comply with government guidelines.

Throughout the pandemic, lessons were learned from working with these unusual restrictions, particularly in the way the Thales team worked with partners Motorola and the customer, Transport for London (TfL). New and innovative ways of collaborative remote testing were devised and implemented which will allow efficiencies to be realised in the future even after the pandemic is long gone.

“Being open with our customer and suppliers was critical. It made sure there were no surprises and, in fact, the customer helped us to resolve problems by working around them. This achievement was all about collaboration, not just Thales delivering to a customer.” - Thales’s Programme Director, Peter Gaylor

The final stage of the replacement work will be removing the obsolete equipment, which starts in February. Thales has been awarded a contract to upgrade London Underground’s radio basestation equipment and has a four-year contract until 2023, with extension options beyond, to maintain the Connect communications system. 

Chief Technology Officer at Transport for London, Shashi Verma, said:

Having reliable access and communication with our staff above and below ground is vital in ensuring we can run a safe network. This upgrade to the Connect radio system has been delivered despite challenging times due to the pandemic, which is testament to the hard work and planning that has gone into this important project.