OnCorr, the second and largest piece of the GO Expansion program, recently saw the first pieces of permanent infrastructure installed.

They are survey monument structures that will help establish a control network across the transit system.

These survey monuments will allow Metrolinx and ONxpress, Metrolinx's partner for OnCorr, to carry out faster construction and maintenance, as well as improve safety and access for project teams.

If you’re not familiar, GO Expansion is a transformative program which will bring faster, more frequent train service to the region by adding more trains, more stations, more options, and more connections to support population growth, alleviate traffic congestion and give customers more time to do the things they love.

In fact, there are over $11 billion of GO Expansion projects that are already completed or in construction across the region.

Survey monument installation

Since Oct. 2023, almost 60 survey monuments have been installed on each side of the Lakeshore West corridor, spanning a 6km stretch between Burlington and Appleby GO Stations. This is the first phase of the deployment that will serve as a test case for the network.

Once the test case results are in and the ideal solution is determined, over 400 more monuments could be added across the network this year.

If implemented fully, this approach will provide an efficient long-term solution and create a standardized series of control points across the network for all future infrastructure improvements over the next 30 years.

What exactly are survey monuments?

Survey monuments sit anywhere from ground level to 1.5 metres above ground, and help determine elevation benchmarks, track rail movements, and assess ground conditions around the train tracks. Different types of structures currently being tested are made of concrete, steel, and brass.

By installing permanent survey infrastructure in this area, the ONxpress survey team will be able to observe how different types of survey monuments behave and settle over time in one of the busiest areas on the GO Train network.

The survey team will also be able to determine the correct density (distance between monuments) necessary for data, GPS, and image collection ahead of this transformative transit project.

Why start with this section of the Lakeshore West Line out to Burlington?

“This site was the farthest away from Union Station while still on a busy priority line that will be electrified,” said Dougal Medley, survey project manager at ONxpress.

The work also took place overnight to reduce customer impacts and keep trains running on time.

Any rail network of this magnitude requires various construction activities to keep the corridors in a state of good repair, including renovation and maintenance.

Planning for this trial run began in June 2022, when the survey team developed a business case to demonstrate the benefits and value-for-money in taking this type of approach. This is a first-in-Ontario solution, as generally speaking, all survey work on rail is done on a much smaller scale and project-by-project basis.

Does “due diligence & investigations” sound familiar?

Survey monument installation work is part of the wider due diligence and investigations (DD&I) work for the GO Expansion – On-Corridor Works project, which involves surveying rail corridors to collect topographic data and a detailed inspection of each line for future design and construction activities.

This work supports a plan that is all about bringing more train service so that customers can enjoy shorter journey times, improved connections, and more options to get where they need to go better, faster, and easier.

When complete, GO Expansion will deliver faster, more frequent, electrified service that will fundamentally change the way people move throughout the region.