European Antennas Ltd has designed and manufactured antennas for Thales for use on Section 2 of the Channel Tunnel Rail Link (CTRL) project between Fawkham Junction in Kent and London St Pancras International station.

Section 2 of the CTRL includes the provision of 65km of new high speed track allowing speeds of up to 186mph (300km/hr), bridges and structures along the route, and the construction of the three developments at St Pancras, Stratford and Ebbsfleet stations.

Thales was targeted with several key tasks relating to communications within CTRL including improved GSM-R and Cab Secure Radio (CSR) coverage for the railway operators in order to maximise safety and to provide coverage for the London Fire Brigade in evacuation shafts from CTRL tunnels and passenger exit shafts.

Thales appointed European Antennas Ltd to design and manufacture a range of single and multi-band antennas.

The prestigious, demanding CTRL civil engineering project presented unique challenges for wireless communications with 25% of the route in tunnels, with trains travelling at speeds of up to 150mph.

An environmental feature of this application was the wind speed caused by trains within tunnels and resultant vibration that would have to be absorbed. Antennas would therefore need to be impervious to their surroundings, be tough, reliable, have low wind loading and meet the RF requirements to an uncompromising specification. Antennas for installation within St Pancras International would need to be discreet in appearance to merge within the magnificent new station.

European Antennas designed eight antennas to meet these requirements. All had specific power levels and covered the frequencies for GSM-R, Cab Secure Radio and the London Fire Brigade services.

One of the development projects undertaken was that of a slim panel antenna to support the emergency services system in London tunnels and the associated emergency evacuation routes. Mounted inside a firewall of an evacuation tunnel, this antenna features long length insulated cable so that the radio could be mounted at a safe distance to ensure its use in an emergency. The antenna still maintained 8.4dBi gain and full coverage down the shaft.