Project Life Cycle

Construction

Metrolinx brings its transit projects to life through various phases of construction activities.

Pre-planning and Due Diligence & Investigations

Before we can put shovels in the ground for a project, we need to work with our contractors in a pre-planning phase to do early inspection work, also known as due diligence and investigations (DD&I). During this phase, we physically check the existing conditions of the infrastructure to plan how we'll build the project and to gain a strong understanding of how the project will integrate with the existing environment and broader transit network. The goal is to find out what details of the project can be improved so that we can start early construction work on a strong foundation. 

Early Works

Early works are the first opportunity to begin construction activities and to prepare for the phases of work ahead. This involves clearing any obstacles in the way, including demolishing buildings or moving utilities that are above or below the ground. This work paves the way for major construction and is key to setting the project up for success.

Learn about some of the essential steps that bridge the gap between the planning and design phases of a project and breaking ground.

Major Works

Major construction starts once we finalize the project’s planning and design phase and clear the construction site with heavy machinery. At this point, we start the key infrastructure activities that will bring the project to life.

One of the major construction activities that plays an important role in expanding transit service across the region is tunnelling, which is essential for building underground subway and LRT routes. Explore our tunnelling section to learn more about the methods Metrolinx employs to construct tunnels in busy urban areas.

Design changes 

As we build our projects, there is a possibility that we may discover infrastructure or environmental conditions that we weren’t previously aware of during the project's design phase. This could include old or aging utilities, sensitive environmental ecosystems, archaeological findings, or culturally sensitive landmarks – any of which could present a challenge in continuing to deliver the project.  

If our teams discover any of these potential roadblocks, we may need to alter the design of the project to accommodate the new findings. At this point, our teams work together to update the project’s design and make sure any changes we make are safe, conform to our project goals and requirements, and keep the project on track.  

Testing and Commissioning

As construction progresses, it’s important that our project is on schedule and meets the safety and design standards that we developed earlier on in the project’s life cycle. 

Metrolinx’s testing and commissioning process was created in line with worldwide industry practices for other major infrastructure projects.  

Our expert teams need to ensure everything is designed, developed, and installed according to the design requirements, and that it is safe for anyone that may interact with the project’s infrastructure. This includes maintenance and safety workers, transit operators, customers, and the community. 

Following the inspection, our teams will test the project’s infrastructure before we put it into service. This step ensures that all the individual aspects of a project are working properly and together before we can integrate it with any other transit systems or services. 

Project Completion

A Metrolinx capital project is complete when we finish all the work outlined in the contract and it meets our requirements – the project is now ready to come online. 

There are varying levels of completion, including: 

Substantial completion 

Substantial completion means that a project is sufficiently complete, and we can use it for its intended purpose. At this point, we may take possession of the property and start operating it. From here, we may need to complete some finishing touches, such as landscaping, painting, and tiling, as well as ironing out any deficiencies that we may have found during the testing and commissioning phase.  

Total completion 

Total completion means that we’ve finished all the necessary work, including making all the finishing touches and addressing any outstanding issues – the project is now 100% complete.