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London TETRA, United Kingdom

Key Data

Motorola, along with industry partners Racal Translink and Fluor Daniel, were awarded the contract in November 2000 to replace and manage the radio and transmission services for the entire London Underground network. Known as Connect, this Private Finance Initiative (PFI) project is worth £1.2 billion over 20 years. Motorola, as part of the CityLink Consortium, will be implementing one of the largest and most complex private business radio services ever provided in Britain. At the heart of the solution is Dimetra technology - a digital radio system based on TETRA (Terrestrial Trunked Radio), the only ETSI-approved standard for professional mobile radio. TETRA is the most significant wireless standard to emerge from ETSI since GSM (Global System for Mobile Communications).


Under Connect, LUL (London Underground Limited) will procure enhanced radio services delivered through a new TETRA digital radio system to provide integrated mobile communications to trains, stations and depots across the underground. The new communications systems also encompass an optical fibre, high-speed transmission network to support services such as telephony, data, customer information systems and video transmission, with sufficient capacity for future communications requirements.

In the implementation of Connect, Racal Translink is responsible for network operations over the life of the contract. Fluor Global Services has overall responsibility for the four-year new build programme and has awarded sub-contracts to Motorola, who will provide the TETRA-based digital radio system, and Racal Translink, who will design and supply the transmission network.

CityLink Telecommunication's solution gives LUL a performance-based service with the technical risks of provision, as well as the financial risks associated with funding the project, being transferred to the private sector. The company begins operating the existing systems and will proceed with the design of the new systems with immediate effect.

The underground will benefit from the implementation of an interim upgrade to rectify the most pressing faults and high-risk failure points. This will stabilise the existing systems and pave the way for short-term service improvements prior to the installation of the new systems underground, planned for completion within four years. Under the new build programme, the first lines due for renewal are the District, Piccadilly and Metropolitan lines, with the remainder completed by 2004.


APD Communications Ltd, a wholly-owned subsidiary of Lynx Group plc, has been selected by Motorola Ltd to provide mobile data and control room applications for the new London (LUL) communications network. Under the five year contract Lynx will supply mobile communications units for all underground trains and provide control room software, which will run using the latest TETRA standards. Development for the in-train devices began immediately and the first installations started to be put in place from mid-2001.

The expected improvements to operational efficiency and enhanced communications capabilities will benefit the 800 million passengers who travel on the underground each year. TETRA allows for combined voice and data communications, enabling drivers to send and receive digital quality voice and short text messages. This will improve efficiency as drivers can both send and receive individual or broadcast messages and the control room can quickly re-deploy trains, resolving disruptions more quickly and improving passenger flow. The system will allow real-time information exchange between trains, stations and depots. Each train will be monitored by a control room system, based upon Lynx's Cortex integrated control system.


All the systems to be supplied form a part of the Connect project, the key benefits of which are:

  • Integrated communications across all London Underground's depots, stations, trains and offices
  • Enhanced communications facilities from a fibre-optic network customer information, short text messaging, video transmission, PC applications such as internet access
  • Spare capacity in transmission network allows for cellular mobile capability at station platforms and moving image advertising facility.
  • Digital CCTV for added safety and improved emergency response