Bridgeway Consulting was commissioned to undertake a track monitoring project at Camley Street near St. Pancras Station to monitor track deflection during demolition and construction adjacent to open lines. The site was approximately 150m long, with four NR lines close to site (2 sidings and the Up & Down fasts) where settlement, heave, twist and cant were to be monitored at 3m intervals. Monitoring was planned to be undertaken 24/7, for an initial period of 26 weeks, then extendable to 12 months. Although the job was initially planned using traditional total station methodology, Bridgeway decided to use Senceive’s technology as a more stable, and lower maintenance alternative solution.
Under extremely limited access periods, a joint Senceive and Bridgeway team installed a total of 214 individual high precision and stable tilt sensors to the sleepers and bridge deck, forming a digital mesh able to report cant/twist/heave. The system is completely wireless with only 3 solar GPRS gateways mounted on bolted posts. In addition, some selected sensors were placed on beams nearby to monitor possible impact on a Network Rail owned building. Sensors are encased in hardened aluminium enclosures with low profile aerials. With the sensor having battery life of up to 15 years and the gateways operating with solar power no mains power is required.
Sensors were baselined even as engineers left site with accurate and stable data continuously and consistently delivered since the start of the project. Typical difficulties with other optical or wireless monitoring systems in managing multiple NR lines in a stable and repeatable manner have been completely overcome with FlatMesh; no more false alerts!