Walsh Construction, Chicago

O’Hare Airport Rail Construction Monitoring

A track upgrade project in Chicago has once again demonstrated the versatility and ease of use of wireless remote condition monitoring technology.  Walsh Construction started using wireless tilt sensors to measure changes in rail track geometry during adjacent construction activity related to expansion works at O’Hare Airport in 2022. They have continued to find value in the technology as the infrastructure upgrade continues.

One challenging aspect of the project involves re-alignment of a section of two mainline Class 1 freight tracks, which requires significant excavation works adjacent to the line, whilst Union Pacific trains are still running. Engineers designed a system of structural steel bracing to support the sides of the excavations. The design requires these soil retention structures to be progressively extended as the construction works progress along the route. In order to proceed with confidence and to safeguard the railroad, a decision was made to monitor the stability of both the adjacent tracks and the excavations using wireless tilt sensors.

The new sensors arrive pre-configured and connect to the pre-existing wireless mesh network automatically.  This type of highly flexible IoT technology is ideal for busy construction environments. The components are small, robust and need no cables for power supply or communications. As can be seen in the photos, the Nano tilt sensor nodes can be simply fixed to the steel at any orientation using quick grab adhesive. Once installed, they provide precise 24/7 realtime monitoring with no concerns about line of sight and no need for frequent visits by surveyors.

Around 400 track sensors have been deployed so far, covering a 2,000 foot length of the two mainline freight tracks. And within the excavations a total of 20 nodes have been installed on the horizontal bracing steelwork. The data from both sets of sensors has demonstrated acceptable levels of movement within the pre-set thresholds.

The monitoring program included the tracks above the excavation and both the upper and lower steel bracing structure

Nano tilt sensor node installed on steel bracing using quick grab adhesive