a electric train


Building a strong foundation for GO Expansion’s OnCorr project

Look back at the work done over the last two years on this unprecedented transit expansion project.

Apr 26, 2024

With early works construction expected to start later this year, the GO Expansion program is now closer than ever to bringing faster, more frequent GO Train service to the busiest parts of the network including parts of Lakeshore East and West, Stouffville, Kitchener, and Barrie GO lines. 

GO Expansion is being delivered through over 200 interconnected projects through two different portfolios: Early and Complementary Works, and On-Corridor Works. 

On-Corridor Works (or, OnCorr) is the second, and largest, project within the GO Expansion program, and is currently in the development phase. 

One of the main goals of OnCorr is to unlock capacity across the GO network to add more trains and save riders time when travelling on core segments of the network. 

This will be achieved through introducing a new signalling system, overhead electrification, improving Union Station at track level, a new and modified fleet, and a range of targeted civil and track investments throughout the network. 

The sheer size and complexity of this unprecedented project requires a large-scale planning and design period before major construction starts, called the development phase.

GO Expansion renderings

Artist's rendering of electrified service. Designs are subject to change. (Metrolinx photo)

Development phase progress so far

In 2022, Metrolinx and ONxpress Transportation Partners (ONxpress) entered into the development phase – a large scale planning and design period to determine many design and construction details prior to major construction beginning. The main function of the development phase is to finalize scope, design, and cost for the project. 

Over the past 2 years of the development phase, big strides have been taken to design and plan the project – all while GO Transit service continues to operate.  

Lakeshore East GO Construction 2

Planning in advance helps keep the expansion project on schedule. (Metrolinx photo)

Creating the GO Expansion “delivery machine” 

A unique consideration when planning for the scale of the GO Expansion build is how to construct on the rail corridor when trains are running during the day to limit service disruptions as much as possible. 

Work is well-underway on planning for how, and when, work crews can access the rail corridors in the coming years to create stable and consistent construction sites. This advance planning will help keep the project on schedule and create the space within the rail corridor in a way that minimizes disruptions.  

Accessing the rail corridor is just one way the GO Expansion “delivery machine” is being created. Another approach to ensure optimal delivery of the project is the introduction of logistics hubs.  

Logistics hubs will be locations next to the rail corridor where materials and equipment for construction will be received and stored. They will also support assembly and production, while playing a key role in supplying the materials and equipment needed for construction via the rail corridors.

Throughout the development phase, Metrolinx has also been working on securing rail-based construction equipment.

So far, Metrolinx has ordered 3 three universal tamping machines and three ballast regulators which are in production to arrive in early 2025. 

GO Expansion development phase

A high-productivity tamper machine – part of Metrolinx’s rail-based construction equipment. (Metrolinx photo)

Gathering information about the rail corridor 

Due diligence and investigations (DD&I) for OnCorr is well-underway and is gathering information about conditions along the rail corridor, to help engineers plan custom approaches for each area, resulting in the best project for our customers.  

So far, as part of DD&I work, over 130 environmental field investigations have been done, and more than 280 boreholes have been drilled to inspect soil conditions. Utility investigations are well underway with over 80 per cent of investigations done in corridors and the Union Station Rail Corridor (USRC).

These are a key step in documenting utilities, as well as the natural environmental features of each area, have been completed. 



Starting in October 2023, survey monuments were installed along a segment of the Lakeshore West corridor, marking the first pieces of permanent infrastructure installed as part of OnCorr. These survey monuments will make it easier for Metrolinx and ONxpress to carry out faster construction and maintenance, as well as improve safety and access for project teams.

GO Expansion renderings

Artist's rendering of electrified service. Designs are subject to change. (Metrolinx photo)

A new operations partnership 

In December 2023, Metrolinx accepted ONxpress’ proposal for the operations and maintenance of the GO Transit system beginning Jan. 1, 2025. This means that, next year, ONxpress will start operating and maintaining GO Trains, train service planning, introducing new operational technology and providing maintenance services for new assets like electrification and signaling. 

These critical activities inform the overall plan for the project. They allow for a holistic approach to be taken during the design process to decide the sequence of work, coordinate logistics, and purchasing equipment that requires longer lead times. All of this ensures there are no surprises when work ramps up.  

GO Expansion renderings

Artist's rendering of electrified service. Designs are subject to change. (Metrolinx photo)

Looking ahead 

Design for the project is nearing completion, and when complete, the project will be delivered in phases.  

Some early works are expected to begin later this year with the start of construction of several hubs to form a logistics network across the GO network.  

Updates regarding construction for the next project phases are expected in 2025.  

Stock GO Train at willowbrook

More transit means more choice and affordability in keeping communities connected. (Metrolinx photo)

Building more transit for the region 

We’re working to bring you more rapid transit, closer to home. From more routes to new stations with more ways to pay. 

It’s all part of the integrated expansion plan to improve transit across the Greater Toronto and Hamilton area, which stretches from Barrie to Niagara, Kitchener to Oshawa and beyond.  

The GO Expansion program is a key part of that plan, which will bring faster, more frequent train service to the region by adding more trains, more stations, and more connections to support population growth, alleviate traffic congestion and give people more time to do the things they love.