Kings Cross Rail Tunnel Monitoring

The area around King’s Cross Station had 67 acres of unused land which was designated for development in 2008. The masterplan included 50 buildings, 1,900 new homes, 20 new streets, 26 new public parks and squares and 26 acres of open spaces. The development sites were adjacent to, and straddled, four mainline railway tunnels that served Kings Cross Station. Network Rail agreed the development could proceed, provided predicted movement of the tunnels and track was analysed and measured with a real-time monitoring system.

What we did

Pell Frischmann was contracted to design, install and maintain a suitable monitoring system for the duration of the project. Manned access to the tunnels was highly restricted and the system had to operate automatically 24/7 for 15 years. Monthly maintenance shifts were available, but it was essential to have two independent systems to act as a backup in case of system failure and to check any false readings.

A system of 11 total stations observing prisms attached to the tunnel lining and rail webbing, was backed up with an IoT system consisting of 120 wireless tilt sensors, 80 wireless strain gauges and 16 wireless convergence sensors. All observations were reported automatically to processing software, with graphing and visualisation access for all stakeholders. Any exceedance of the pre-agreed trigger levels generated an automated message to all stakeholders to stop work and initiate further analysis.


The system has operated successfully for 10 years and has been scalable to meet the varying construction activities over that period. Movements have been detected, but analysis and consultation could be undertaken to resolve any issues without the need to stop construction work or delay any train movements. This ensured the work remained on programme, developed a collaborative approach amongst all stakeholders and insured there was no damage to the tunnels or fines for train delays.

Kings Cross Central:

Pell Frischmann provide an innovative solution working closely with the whole team. They have responded promptly to any issues, including out of hours and have saved the project from the costs of any delays to trains.


We’d love to hear from you!

To find out more about Kings Cross Rail Tunnel Monitoring, please contact us through our form here.

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