Heathrow Express Extension – Terminal 5 | UK

Project summary

Service provided:  Monitoring of the existing express rail tunnel during construction of the new tunnel
Location:  london bridge
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Period of the service:  2004-2005
Duration of service:  18 months
Sixense solutions used: 

Images of the project

A new link rail link for Terminal 5

Heathrow Express is an airport rail link between London Heathrow Airport and London Paddington station. The service opened in 1998 and is operated by the Heathrow Express Operating Authority, a wholly owned subsidiary of Heathrow Airport Holdings Limited.


As part of the extension works at Heathrow Airport, Terminal 5 is to be linked to the existing terminals via the Heathrow Express.



Sixense appointed

Sixense were appointed to carry out the installation and monitoring to the existing Heathrow Express running tunnel between Terminals 3 and 5 during the passage of the tunnel boring machine into the existing turnout stub, and during breakout into the existing tunnel.


A comprehensive monitoring system was installed. This comprised of:



  • 120 Nos. Prisms (Automated Monitoring)


  • 80 Nos. Prisms (Manual Monitoring)


Real-time movements were monitored and recorded on Sixense’s Geoscope monitoring software. Both Cyclops instruments were driven by a computer installed in the baggage area and linked to the instruments by a data cable running along the tunnel lining.


Another computer was installed in the contractor’s control room and linked to the baggage area via a modem. This allowed the monitoring engineer and contractor to assess and review movements of the tunnel in real time.


A remote alarm system was also installed within the Heathrow Express control room and linked to the monitoring engineer’s PC via a phone line. This alarm system would activate a flashing warning light if triggers were breached, allowing the control room staff to stop train movements immediately and ensure passenger safety.


Terminal 5 opened on 27th March 2008 and the full Heathrow Express service to T5 opened on 23rd June the same year.

Project Key figures

2 Nos. Automated Total Stations
120 Nos. Prisms
80 Nos. manually read prisms
24 Hours attendance during critical phases of TBM passage

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