Successful Completion of Highway 401 & 409 Rail-Tunnels

A major tunnel upgrade and excavation project

The existing Kitchener Corridor with three (3) live rails is in the City of Toronto, Ontario, next to Toronto Pearson International Airport. To bring more frequent service to GO Transit customers, Metrolinx and Infrastructure Ontario started a twin tunnel construction in 2018. This infrastructure upgrade is taking place less than three meters underneath Highways 401 and 409 – all without disrupting the continuous traffic flow above.


Sixense provided a tailor-made monitoring solution in a challenging environment

Sixense was chosen by Toronto Tunnel Partners (TTP), a joint venture between STRABAG Inc. and EllisDon Civil Ltd. to perform environmental, geotechnical, and structural monitoring of the existing rail tunnel and twenty-one (21) lanes of live Highway, 401 and 409, one of North America’s busiest highway corridor.

In order to achieve the required high spatial density, and high-frequency monitoring while minimizing interruptions of existing highway traffic and manual readings in heavy traffic areas, an innovative near real-time deformation monitoring system was designed and implemented. It consists of 8 Sixense’s Centuar automatic motorized total station (AMTS) with over 450 reflector-less points on the highway and 3 AMTS in the existing rail tunnel, complemented by Shape Arrays, In-place Inclinometers, Piezometers, Tiltmeters, Vibration and Noise Monitoring.


Completion of a milestone for the Highway 401 & 409 Rail-Tunnels

On January 22, 2021, the project reached a big milestone by successfully finishing the second tunnel excavation. Sixense’s expertise and dedication to the continued success of the project are well recognized by the project team. The new tunnels support the GO Expansion program and will transform the Kitchener line into a more convenient two-way, all-day train service.


Click here to learn more about this project.